Mazzei bypass, parallel advanced plumbing

[Gerryd]

Hey all,

I need some assistance (as usual) with understanding static pressure and mazzei performance with a parallel closed loop configuration.

This is a long, boring, and detailed thread with many questions, so be forewarned! If this is not your thing, please do yourself a favor and move on to the next thread lol

I realize that these issues may be related, so if any of my assumptions or 'facts' are untrue, shout out!

Background info:

180 gal 72x24x24 with twin overflows and drilled intake/outtake.
Seup is all 1" diameter intake to pump and 1" diameter from pump until the 3/4 dual outlet split back to the tank. End to end, the output flow travel distance is 2' up to the parallel legs, and then 2 parallel legs of 5', then 4' to the split,
and then 6' of combined split for 22' of total length from pump to tank with 2 canisters and the bypass at the beginning of flow.
Looking at the canisters while running they seem to be getting good flow through them
Loc-line outlets produce good flow from all 6 ports. Some are stronger than others but I attribute this to the wye split from 1 to 3 on each side.
Overflow boxes are getting good flow into them.
Tank is clean and clear. Growth very good, no algae to speak of.
PVC flex was used to connect components.
Venturi bypass assembly is all 1" PVC.

Please use the pic link to follow along

Detailed Parallel pictures by gerrydirish - Photobucket

Pic 1 shows the Pump (Pan World 250PS) in the back which goes to Main throttle valve (V1) to a T (T1) and to a 45 Elbow. Flow is from left to right
and you can see the connections to the NC canisters at each leg. This is the start of the two parallel legs.
Pic 2 shows the venturi bypass assembly for the first parallel leg. To the left of this and unseen is the NC 547 bio unit. You can see the 533 mech unit in front.
Pic 3 shows the straight leg of the T connects to a 45 degree elbow and the second leg which contains a throttle valve (V2) and then the 533 NC mech canister (not shown).
Pic 4 shows a closeup of the venturi bypass and Lifeguard PSI guage on the straight leg along with a throttle valve (V3) which controls the amount of water flowing up to'
the mazzei itself. Note the ball valves (V4 and V5) fore and aft of the venturi.
Pics 5 and 8 show the two legs and how they are ended in 45 degree elbows and then connected to the straight legs of a second T (T2).
Pic 6 shows Flex hose then is used to connect to a WYE for the dual return split.
Pic 7 shows that each return contains a check valve to prevent water from flowing backwards towards the pump but then a throttle valve to control
flow to the tank. These are prior to the drilled intake under the tank.
Pic 9 shows the use of true unions to connect the input/outlet of components.

The NC 533 PSI guage is thus on the furthest leg from the pump, past the elbow and throttle valve about 24" away. The lifeguard guage is on the
leg closer to the pump, but on the off leg of the T, but AFTER the NC 547 bio and well into the bypass itself and is about 30" away.

So, this means that the second leg which has the throttle valve controls the amount of flow to the first leg. (note to self to install valve on leg 1).
The venturi flow is whatever the mech side does not utilize and also gets past the NC 547 bio. The flow/pressure to the mazzei is controlled by the
main throttle valve on the bypass straight leg after the guage. A ball valve is installed on each side of the mazzei itself.

V1 = main pump throttle valve.
V2 = throttle valve on second parallel leg. Prior to NC 533 mech.
V3 = Main venturi bypass throttle valve on straight leg.
V4 = throttle valve pre-venturi on the off leg of the loop
V5 = throttle valve post-venturi on the off leg of the loop

G1 = guage on NC 533
G2 = guage prior to V3 on venturi bypass assembly.

Following tests were with the NC 533 mech cartridge REMOVED.

UPDATE: the 533 cartridge was installed and the same tests performed. No visible differences in PSI found
from the test w/o the media.

Test 0 - with the siphon broken, I show G1=0 and G2 at 3.5.

Test 1 = Readings with the pump OFF and ALL other valves open:

G1 = 0
G2 = 5

Remaining tests with pump ON.

Test 2 = all other valves open:

G1=12.5
G2=17.5

Test 3 = All valves open except for BOTH return line valves are CLOSED as a full pressure test:

G1=20 - expected as the max rating for this pump is around 19-20 PSI
G2=25 - again the 5 PSI difference consistent between the two guages

At this test, BOTH NC leaked at the lid seal but did not once the valves were reopened.

Note the 5 PSI differential between the two guages is carried forward.

BTW, another lifeguard PSI guage I have that is new shows 3.5 on the dial out of the box.....
With the siphon BROKEN the venturi guage G1 reads this same value.

Test 5 = V2 closed and all others open:

G1=10.5 - reduces slightly 2 psi as opposed to Test 2.
G2=17.5 - unchanged from Test 2

Test 6 = V3 closed and all others open:

G1=12.5 unchanged from Test 2.
G2=18.5 - increases slightly 1 psi from Test 2.

It seems I am NOT getting visible PSI differences in BOTH guages when opening/closing various valves.

Assumptions

1: These PSI values should be very close to each other if not the exact same?????
2. That the lifeguard guage should read 0 like the NC guage does with no water in that pipe?
3. The max pressure is most likely 19-20.
4. The parallel PSI on both legs is most likely 11-13 using the NC guage as a guide.

Initial qestions:

1. Are the assumptions above valid?
2. Why don't both guages show the same reading at all times in Tests 1-3 if TRULY in parallel?
3. What is my ACTUAL static pressure? Could it be 1.5? Subtracting the PSI with and w/o siphon (5-3.5) and it doesn't show on both guages? Makes no sense. I could see 1-2 PSI from a 6' drop from the top of the intakes to the pump but not quite that much (5???). Could it be related to the check valves I used on each return line?
Do these add anything to the equation?
4. Why don't the readings change more in tests 5 and 6? I would think they would balance each other out????

I would like to have 5-6 PSI going to the mech unit which is why I have the throttle valve on this leg and not the other. However, even shutting this completely, my NC guage still reads 10.5 and the other guage hardly changes? Why is that? I can get the G1 value < 10 ONLY by ALSO closing V3 and V2 together. This produces the best mist............

I know both guages read 0 when I was installing it and did not have a reading until the system was filled with water.
The NC guage has only the media (removed for these tests) and then some flex hose behind it, while the other guage has the open throttle valve
and the rest of the bypass assembly behind it, before the join back to the return split.I made both legs the SAME length and connect to the T
in the same way albeit with different components per leg. You can see this in the album.

All of this playing around brings me to my second issue:

The best performance from the venturi seems to be when V2 is 50% closed and V3 is 90% closed. G1 reads 5 and G2 reads
22. This however causes the NC bio unit to leak at the lid seal as I assume it is not meant to deal with this amount of pressure. Tightening the
clamp did no good and made it worse. I will check the seal tomorrow at WC time. Opening V3 more and the leak went away with the clamp
at it;s original tightness.

After this 15 minutes of this PSI testing, there was increased misting and some moss close to one of the outlets dramatically increased pearling also
reflected in other plants.

So, if I need to create that much back pressure to get the best c02 mist performance, how not to blow the gasket on the bio unit?

Am I missing some big thing about parallel configurations that is not sinking in?

As always, thanks in advance and appreciate any thoughts.

 

[jeremy v]

Gerry,

1. Are the assumptions above valid?

Yes, if there is any place in your system with a gauge reading a higher pressure than your pump can reach (max psi you can achieve is the max head pressure of your pump divided by 2.3) the gauge is giving you a bad and inaccurate reading.

2. Why don't both gauges show the same reading at all times in Tests 1-3 if TRULY in parallel?

Any gauge that is separated from another gauge by only PVC plumbing should read the same pressures at all times. Pressure losses through the pipes themselves will be pretty much non-existent for the distances you have between gauges and the flow rates you have, so they can be ignored for your purposes. System pressure will only change in a measurable way when the water goes through a NC canister, check valve, ball valve that is partially shut, etc.

3. What is my ACTUAL static pressure? Could it be 1.5? Subtracting the PSI with and w/o siphon (5-3.5) and it doesn't show on both guages? Makes no sense. I could see 1-2 PSI from a 6' drop from the top of the intakes to the pump but not quite that much (5???). Could it be related to the check valves I used on each return line?

Your static pressure reading will be based completely on the vertical height difference between the particular gauge you are reading and the tank water surface when you have the pump turned off and a complete siphon throughout the entire plumbing system. Measure the height between the tank water surface and the gauge you want to check the accuracy of, and divide the measurement (in feet) by 2.3 and that will give you the psi rating the gauge should be reading. If the gauge is reading anything different that particular gauge is not accurate.

Do these add anything to the equation?
4. Why don't the readings change more in tests 5 and 6? I would think they would balance each other out????

First, do your pressure gauges have any sort of a calibration screw anywhere on them so that you can at least zero them all out so they are more accurate for comparison purposes? It doesn’t inspire much trust in the gauge readings if they start out several psi off right out of the box and they can’t be zeroed out.

In relation to your question about the check valves on your returns, yes they will eat up a little bit of pressure from the water going through them, how much will depend on the type of check valve you are using. If they are the “flapper type” that has a rubber flapper inside the housing there should be a marking on the housing somewhere indicating which side of the valve needs to be the top when mounted horizontally in order to ensure that the valve will close correctly when the water flow is shut off. That type will not have much water pressure loss at all, because the water flowing through it only has to push a simple flapper open to get through. If your check valves are the “spring type” the valve's orientation makes no difference for proper operation, but a trade off is that the water pressure has to push and compress a spring in order to open the valve and get through. Most of the spring type valves need about 0.5psi before the spring starts to compress, but some check valves with stronger springs can need as much as 2psi or so of water pressure before the spring begins to open. The exact same brand of check valves can open a little bit easier or harder than others as well, so that might be giving you a slight variance in return line pressures, but I would be very surprised if it would ever be more than a 0.5-1psi difference max.

In as far as your canister leaking when you have the pressure increased in order to provide the best mazzei performance, if you put a ball valve right before the canister that is leaking that should solve your issue if I have it all pictured correctly in my head. You will most likely not see a difference until the new ball valve is shut at least 50%, but after that the more you close the new ball valve the more the pressure will drop across the ball valve itself instead of going through into the canister and causing a leak. That will lower the pressure of the water within the canister that is now leaking and it should allow you to keep the mazzei pressure up and keep the canisters from leaking. That will increase your total system pressure and reduce your total system flow though, so that is a trade-off.

Have a good one, Jeremy

P.S.- You mentioned that when you increase the pressure of the water going through the mazzei you get better pearling and more mist. The more pressure that you put through the mazzei the more vacuum is created at the CO2 input line connected to the mazzei. Vacuum is just another way of saying negative pressure, so if you have your needle valve on your CO2 tank set for a certain bubble rate that bubble rate will increase on its' own when you increase the vacuum on the output side of the needle valve. You are essentially creating a larger pressure difference across the needle valve and that will increase your bubble rate without you adjusting your needle valve at all. If you have a good quality fine mist at the pressures you have been running through the mazzei under normal conditions, increasing the mazzei pressure is most likely just causing the pressure difference across the needle valve to increase which pulls more CO2 into the mazzei, so you could achieve the same result (more mist and better pearling) by just increasing your bubble rate some via the needle valve and then keeping the water pressure through the mazzei the way it is. The system as a whole will be more efficient that way, and you will be able to keep your existing higher flow rates as well.

 

[jeremy v]

Gerry,

Assumptions:

1: These PSI values should be very close to each other if not the exact same?????

No, there is a pressure drop across the venturi between the two gauges in the scenarios that you gave, and that is giving you the difference. When V2 is shut the only way pressure is getting to G1 is by going through the venturi after passing G2, so the pressure difference (if the readings were accurate) would tell you the pressure drop across the venturi for that particular setup of valves being open and closed. The two gauges would only read the same value if there was absolutely nothing but unobstructed plumbing between the two gauges. Check valves, partially closed ball valves, NC canisters, venturis, etc. all cause at least a slight pressure drop across them creating a difference.

2. That the lifeguard gauge should read 0 like the NC gauge does with no water in that pipe?

Yes it should, is there an adjustment screw on the rainbow gauge anywhere for zeroing it out prior to installation? Some have one and some don’t.

3. The max pressure is most likely 19-20.

Yes, your pump’s max head pressure (in feet) divided by 2.3 equals your max possible psi anywhere in the system and at that psi reading you would have basically zero flow through the system as a whole. Any gauge readings higher than what your pump can produce are definitely incorrect readings.

4. The parallel PSI in both legs is most likely 11-13 using the NC gauge as a guide.

If that is what the gauge reads under normal operation, yes. Under normal system operation (if there is no pressure loss from the NC 547 canister bio-cartridge itself) both your gauges should read the same value at all times as long as V2 is fully open. I would trust the NC gauge, but I do not trust the Lifeguard one since as you said it read 3.5psi out of the box, haha. Try temporarily removing the bio-cartridge from your NC 547 if possible and run the system with all your ball valves fully open. With that particular setup both gauges should read exactly the same with no chance for any added error factors (possible pressure loss through bio-media cartridge in NC 547). If that is not the case and your Rainbow gauge can’t be adjusted manually to make it match the NC canister, just write the pressure correction factor needed on the Rainbow gauge so that it matches the reading on the NC gauge and then use that same adjustment factor whenever you read the Rainbow gauge in the future. That will be good enough for your application.

2. Why don't both gauges show the same reading at all times in Tests 1-3 if TRULY in parallel?

Any gauge that is separated from another gauge by only PVC plumbing should read the same pressures at all times, parallel or not. Pressure losses through the pipes themselves will be pretty much non-existent for the distances you have between gauges and the flow rates you have, so they can be ignored for your purposes. System pressure will only change in a measurable way when the water goes through a NC canister, check valve, mazzei, ball valve that is partially shut, etc. You have some of those things between your gauges for the different scenarios you outline in your tests causing the pressure differences. The differences are magnified by your Rainbow gauges error though, so that should be fixed first.

3. What is my ACTUAL static pressure? Could it be 1.5? Subtracting the PSI with and w/o siphon (5-3.5) and it doesn't show on both guages? Makes no sense. I could see 1-2 PSI from a 6' drop from the top of the intakes to the pump but not quite that much (5???). Could it be related to the check valves I used on each return line?

Your static pressure reading will be based completely on the vertical height difference between the particular gauge you are reading and the tank water surface when you have the pump turned off and a complete siphon throughout the entire plumbing system. Measure the height between the tank water surface and the gauge you want to check the accuracy of, and divide the measurement (in feet) by 2.3 and that will give you the psi rating the gauge should be reading. If the gauge is reading anything different that particular gauge is not accurate. Your NC 533 G1 gauge should be reading about 1.7-1.8psi assuming the top of your tank is about 5’ off the ground, and your G2 gauge should be reading about 2.1-2.2psi since it is about a foot lower than the G1 gauge.

4. Why don't the readings change more in tests 5 and 6? I would think they would balance each other out????

I don’t know exactly what you mean by “balance each other out”, so I might be interpreting your question wrong. The system does always balance out, but the balance point just changes depending on how you run your setup and adjust the valves in relation to each other. I would expect the pressures to change and be at least slightly different at both gauge locations as a result of all the other factors in your plumbing system coming into play under most if not all circumstances other than the one I outlined above with the bio-cartridge removed and all ball valves completely open. In that circumstance they should both definitely read the same pressure.

In relation to your comment/question about the check valves on your returns, yes they will eat up a little bit of pressure from the water going through them, how much will depend on the type of check valve you are using. If they are the “flapper type” that has a rubber flapper inside the housing there should be a marking on the housing somewhere indicating which side of the valve needs to be the top when mounted horizontally in order to ensure that the valve will close correctly when the water flow is shut off. That type will not have much water pressure loss at all, because the water flowing through it only has to push a simple flapper open to get through. If your check valves are the “spring type” the valve's orientation makes no difference for proper operation, but a trade off is that the water pressure has to push and compress a spring in order to open the valve and get through. Most of the spring type valves need about 0.5psi before the spring starts to compress, but some check valves with stronger springs can need as much as 2psi or so of water pressure before the spring begins to open. The exact same brand of check valves can open a little bit easier or harder than others as well, so that might be giving you a slight variance in return line pressures, but I would be very surprised if it would ever be more than a 0.5psi difference max. If they were different at all in relation to each other you would notice a little bit less total flow coming out of your loc-line outputs on one side of the tank in comparison to the other side of the tank, that’s it.

In as far as your bio-canister leaking when you have the pressure increased in order to provide the best mazzei performance, you can’t correct that without taking the bio unit out of the same parallel loop as your mazzei. You could put it in a new third loop that is set up just like the leg is for your NC 533, or you could add it in series to the NC 533 leg and keep it as a two leg parallel system. I don’t think that is really what is going on though, so if it was me I wouldn’t change anything from how you have it now as long as you are happy with the quality and fineness of CO2 misting you are getting from the mazzei and here’s why. You mentioned that when you increase the pressure of the water going through the mazzei you get better pearling and more mist. More mist is the key. The more water pressure you put through the mazzei the more vacuum the mazzei creates at the CO2 input line connected to the mazzei. Vacuum is just another way of saying negative pressure, so by increasing the vacuum on the output side of the needle valve you are creating a larger total pressure differential across the needle valve, and that will increase your CO2 bubble rate without you adjusting your needle valve at all. What is really going on is that you are just getting better pearling and more mist because you are actually injecting more CO2 than you were before. If you have a good quality fine mist at the lower pressures you have been running through the mazzei under normal conditions, increasing the mazzei pressure is not doing anything but increasing your CO2 bubble rate, so you might as well just leave the mazzei pressures the way they are now so nothing leaks and then increase your CO2 bubble rate via the needle valve as long as the fish don’t mind, haha. The system as a whole will be more efficient that way, and you won’t need to change any plumbing around.

Have a good one, Jeremy

P.S.- That is a good side note as well for all the people out there that are using mazzei’s to inject CO2, and could possibly help keep some fish alive and happy which is what matters most. If you change the water pressure running through your mazzei that will change the negative vacuum pressure that is pulling on the output side of your CO2 needle valve and in turn increase (or decrease as well) your CO2 bubble rate. How much your CO2 bubble rate will change will be based on the magnitude of the venturi's change in generated vacuum, and also how high of a pressure you keep the line side of your needle valve set at via your CO2 tank's pressure regulator. If you want to try and minimize your change in CO2 bubble rate as a result of water pressures through your mazzei changing or being adjusted, keep your CO2 tank’s pressure regulator set to as high of a pressure as possible that can still give you the bubble rate you want through your needle valve. That will ensure that any vacuum pressure changes on the needle valve's output side will remain a much smaller percentage difference in the total pressure drop across the needle valve and keep everything more stable.

 

[shoggoth43]

I'm still having trouble following the plumbing. Do you have a simple line diagram?

Can you swap the two guages? Since they're mechanical devices it's possible one just isn't all that accurate or has a different calibration curve. Unless I've bought the same model I'd always assume it will be. Given that they don't show the same values when off you may have a couple of issues. The obvious is that they probably aren't the same and aren't calibrated the same either. You can get guages which are calibrated to "expected" values and some can be adjusted as well so you could set them all to zero at the "expected" conditions. Usually this is just more $$$ and a wasted of time once you have an idea of what your "normal" vaules should be. A green and red marker will do pretty much the same for you on the dial face.

I would think this calls into question assumptions 1,2 and possibly 4. You don't have the same guages and they aren't calibrated the same. One may not even be accurate if they don't rise the same amount as the other if you pump all of your water just through the sections you can run the guages on.

Also, you are just using simple ball valves for throttle control? One major issue with ball valves is that they really don't give you much in the way of fine control. You get ON or OFF reliably. Anything else is in the range of kinda values. In other words, if you close it and then crack it back open to a known angle you'll get "kinda" 10-20% but going from full ON back to the same twist amount you might end up in the 30% range. They just don't give fine control and that might be giving you some grief. You can get gate valves for this if you really want to tweak for this and they will give you pretty consistent results. I only use ball valves for quick shut offs or to route plumbing for back flushing and not much else because of that. The reef guys with skimmers can definitely give you all sorts of information on that.

-
S

 

[Gerryd]

Jeremy and shoggoth43,

Many thanks for the replies and for sticking through that post!

Shoggoth43,

I'm still having trouble following the plumbing. Do you have a simple line diagram?

Unfortunately no. Pump then ball valve to T and 90 elbow. The T and elbows are parallel legs. One leg has another ball valve and the NC mech, and the other has NO ball valve, the NC bio, and the venturi bypass. These are then rejoined and split back to the tank.

pump
to
flex
to
ball valve
to
flex
to
T to=flex=NC547=flex=venturi assembly=flex=elbow=side of T LEG 1
to
flex
to
elbow to=ball valve=NC 533=flex=elbow=side of T LEG 2

====leg 1=====NC 547 and mazzei
pump=valve=T =====T where legs are joined and flow out
====leg 2=====ball valve, NC 533

The last T is where the two legs are joined. The single leg of the T then goes back across the tank to where the dual returns are split. I will work with Paint and see...........

Can you swap the two guages?

Well I could but would look funny. The NC guage sits like a wall clock and would be face up in the other slot, while the LG guage would then be stuck out in front of the NC...........If you can picture it.

Since they're mechanical devices it's possible one just isn't all that accurate or has a different calibration curve.

Yes, I was afraid that I would end up comparing apples and oranges but what choice do I have? I looked on the web for better quality guages but no luck.

Also, you are just using simple ball valves for throttle control? One major issue with ball valves is that they really don't give you much in the way of fine control. You get ON or OFF reliably.

Yes just ball valves. Good idea on the gate valves, will incorporate in the next phase lol They do work well for what I want to accomplish but can see them in the next upgrade

I read many threads and noone ever wrote in to say they wish they had used gates instead of ball valves, so thought I was okay ha ha.

Yes have been lurking on some reef sites looking for info..............

Jeremy,

Nice to hear from you again..........

No, there is a pressure drop across the venturi between the two gauges in the scenarios that you gave, and that is giving you the difference. When V2 is shut the only way pressure is getting to G1 is by going through the venturi after passing G2, so the pressure difference (if the readings were accurate) would tell you the pressure drop across the venturi for that particular setup of valves being open and closed. The two gauges would only read the same value if there was absolutely nothing but unobstructed plumbing between the two gauges. Check valves, partially closed ball valves, NC canisters, venturis, etc. all cause at least a slight pressure drop across them creating a difference.

I get that but have the following questions:

1. If I shut off the valve fore and aft of the venturi so the bypass doesn't 'know' about the mazzei and drop, wouldn't that 'remove' the difference from the guage? I tried this for fun and there was no difference in either guage.

2. Why would the NC guage read 0? If I understand you correctly (and may not) the NC should read something as the media is behind it and a few feet of pipe/elbow before it is re-joined with the other leg. I find it hard to see how this guage reads 0 at rest.

Yes it should, is there an adjustment screw on the rainbow gauge anywhere for zeroing it out prior to installation? Some have one and some don’t.

No adjustment.

Yes, your pump’s max head pressure (in feet) divided by 2.3 equals your max possible psi anywhere in the system and at that psi reading you would have basically zero flow through the system as a whole. Any gauge readings higher than what your pump can produce are definitely incorrect readings.

Yes, when I did a back pressure test when I first installed the NC 533 the guage read about 19-20 PSI.
So if we assume that the PSI in both legs is around 12 or so, does that mean that I am only flowing the pump capacity at the 28' of head rate? If the max is 19 and I am coming up against 12 already, that is more than 60% of my flow
lost!!!!!!!!!

Could this be why the temp is much higher, as it has to work so hard?

Under normal system operation (if there is no pressure loss from the NC 547 canister bio-cartridge itself) both your gauges should read the same value at all times as long as V2 is fully open. I would trust the NC gauge, but I do not trust the Lifeguard one since as you said it read 3.5psi out of the box, haha.

Yes, I trust the NC guage as well.........BTW, what are normal circumstances? Have I run across them in anything I have posted about?? LOL

Try temporarily removing the bio-cartridge from your NC 547 if possible and run the system with all your ball valves fully open. With that particular setup both gauges should read exactly the same with no chance for any added error factors (possible pressure loss through bio-media cartridge in NC 547).

Will give this a try and see.

If that is not the case and your Rainbow gauge can’t be adjusted manually to make it match the NC canister, just write the pressure correction factor needed on the Rainbow gauge so that it matches the reading on the NC gauge and then use that same adjustment factor whenever you read the Rainbow gauge in the future. That will be good enough for your application.

I agree but cannot trust the guages as they are. Suggestions?

Your static pressure reading will be based completely on the vertical height difference between the particular gauge you are reading and the tank water surface when you have the pump turned off and a complete siphon throughout the entire plumbing system. Measure the height between the tank water surface and the gauge you want to check the accuracy of, and divide the measurement (in feet) by 2.3 and that will give you the psi rating the gauge should be reading. If the gauge is reading anything different that particular gauge is not accurate. Your NC 533 G1 gauge should be reading about 1.7-1.8psi assuming the top of your tank is about 5’ off the ground, and your G2 gauge should be reading about 2.1-2.2psi since it is about a foot lower than the G1 gauge.

I did this and get a bit over 4' using just vertical height. Each guage has an additional 2 or 3' of distance respectively before the guage. So this works out to < 2 PSI at rest.

I don’t know exactly what you mean by “balance each other out”, so I might be interpreting your question wrong. The system does always balance out, but the balance point just changes depending on how you run your setup and adjust the valves in relation to each other. I would expect the pressures to change and be at least slightly different at both gauge locations as a result of all the other factors in your plumbing system coming into play under most if not all circumstances other than the one I outlined above with the bio-cartridge removed and all ball valves completely open. In that circumstance they should both definitely read the same pressure.

I meant that an increase or decrease in guage 1 would have the IMMEDIATE and opposite affect on guage 2. Thanks for clearing this up.

I think they are spring check valves but they do have a flow arrow so am unsure. Am looking up the brand now...........

Yes, got it on the NC bio leak when the pressure is too high. I wasn't totally surprised it happened when looking at the guage reading, but did not think about this when I planned it out..........It seems to work fine as is, but would love to be able to have more control for testing and experimentation.

One final question: Anything to be gained by going to 45 elbows or wyes instead of the T and 45?

Thanks for all of the help and all suggestions are welcome.

 

[jeremy v]

Gerry,

What about just replacing your Lifeguard gauge with a replacement Nu-Clear gauge so at least they are the same gauge. That would keep all the calibrations much more similar and the pressure scale the same on both gauges.

Replacement Pressure Gauge

Yes you are losing about 60% of your max flow from your pump (look at your flow curve for an exact spec on your flow rate) because you are using some of your pump's capacity to generate the pressure needed for your mazzei instead of just using it for flow and that's it.

Your pump should generate about the exact same amount of heat and use about the same amount of power for the entire middle 60% or so of the pump's flow curve. Adjusting your flow levels and system head within this zone will do very little to change the heat put off by your pump or power consumption.

By "normal operation" I just meant when your system is fully operational and running the way you have been running since you changed over to a closed loop configuration.

Have a good one, Jeremy

 

[shoggoth43]

I figured it would be tough to swap the guages but worst case it would at least tell you if they're reasonably similar if the numbers track the same when you swap them. Probably not worth the effort overall. I do wonder if the pressures you're running and flow rates are a problem because of the Tee unions. I don't know if you can swap one or two of them out with a Y type instead so the water flows a little easier. It may make a large difference in your setup because of your pressures.

-
S

 

[Gerryd]

S,

I don't know if you can swap one or two of them out with a Y type instead so the water flows a little easier

Yes, was thinking of this myself. A couple of 90 or a street elbow and wye may help a bit. Worth it for the next install as these pieces are glued...........

Jeremy,

Yes, that is a good idea. Thanks for the link, I had not found these at the time, but found the replacement LG guages. I will grab a few of these. Once I hope I can install on the NC 547 as it has a plug, and the other I can install where the LG guage is........

At least then I will have the same type of guage. Maybe I can get one more at the very output of the pump......

I knew what you meant by 'normal' I was just joking as the simplest task in my hands becomes issues that make no sense, else why would I be asking for more help?

 

[jeremy v]

Gerry,

2. Why would the NC guage read 0? If I understand you correctly (and may not) the NC should read something as the media is behind it and a few feet of pipe/elbow before it is re-joined with the other leg. I find it hard to see how this guage reads 0 at rest.

The NC gauge should only read zero if disconnected from the plumbing system and in open air. When connected to the plumbing setup with a complete siphon and the pump turned off it should read the head pressure of the tank water pushing down on it through the plumbing. Only vertical distance from the gauge to the tank water surface matters in calculating the gauge reading for static pressure.

Yes, when I did a back pressure test when I first installed the NC 533 the guage read about 19-20 PSI.
So if we assume that the PSI in both legs is around 12 or so, does that mean that I am only flowing the pump capacity at the 28' of head rate? If the max is 19 and I am coming up against 12 already, that is more than 60% of my flow
lost!!!!!!!!!

Not lost, just converted. Pumps can produce flow, pressure, or a combination of both. Your setup right now is causing the pump to use 40% of its' available power to create flow and 60% or so of its' power to generate the pressure needed to run your mazzei, etc.

Could this be why the temp is much higher, as it has to work so hard?

You are right in the middle range of the pump's flow curve which is the most efficient zone in as far as the amount of work accomplished by the pump in relation to the electrical power required by the pump. You are not working the pump hard at all, you are right in the zone the pump was designed to run optimally.

I agree but cannot trust the guages as they are. Suggestions?

I would trust the NC gauge. To be honest the main purpose of your gauges should really only be to help you know when to clean filter cartridges and that's about it. If everything is running fine, the plants are happy, the mazzei is working well, and you are happy with your setup I wouldn't worry about what the gauges say at all other than to keep an eye on filter clogging levels.

I think they are spring check valves but they do have a flow arrow so am unsure. Am looking up the brand now...........

If the housing only has a water flow directional arrow they are most likely spring valves, the flapper type would have a directional arrow and an additional marking somewhere that says "TOP" as well for horizontally mounted circumstances.

Yes, got it on the NC bio leak when the pressure is too high. I wasn't totally surprised it happened when looking at the guage reading, but did not think about this when I planned it out..........It seems to work fine as is, but would love to be able to have more control for testing and experimentation.

For the most control possible for testing and experimentation you should put the bio-canister on a third parallel leg and have a ball valve right before the canister just like you do for the mechanical filter. That would allow you to set pressure levels and flow rates through each item in your system individually. No matter what though, changing the flow rates through one item will change the flow rates and pressures through the others as well, so they will never be totally independent unless you had each item with its' own individual pump and plumbing to and from the tank. You would be able to set the mazzei at a much higher pressure that way if you wanted though, but that would cut your total flow rates down as well, so there is always a trade-off.

Thanks for all of the help.

No problem.

Have a good one, Jeremy

 

[Gerryd]

Jeremy,

The NC gauge should only read zero if disconnected from the plumbing system and in open air. When connected to the plumbing setup with a complete siphon and the pump turned off it should read the head pressure of the tank water pushing down on it through the plumbing. Only vertical distance from the gauge to the tank water surface matters in calculating the gauge reading for static pressure.

I agree and am still wondering why it reads 0. There is most certainly a siphon as it reads this after hours of operation and the pump is shut off.

Would just like to know why is all. If there is a reason, maybe it indicates a problem somewhere.......

Not lost, just converted. Pumps can produce flow, pressure, or a combination of both. Your setup right now is causing the pump to use 40% of its' available power to create flow and 60% or so of its' power to generate the pressure needed to run your mazzei, etc.

Yes, I forgot this lesson from a previous reply of yours on running series vs parallel.

Thanks for the temp info. Makes sense, but this is a lingering issue and would like to have a 'cause' if not a cure.........

I would trust the NC gauge. To be honest the main purpose of your gauges should really only be to help you know when to clean filter cartridges and that's about it. If everything is running fine, the plants are happy, the mazzei is working well, and you are happy with your setup I wouldn't worry about what the gauges say at all other than to keep an eye on filter clogging levels.

I agree, I was just hoping for the guages to give me some numbers that were 'close' to reality, just for my own information.

However, I used to run only the NC with 5-6 PSI on the guage, and now it is twice that......I can watch the guage, but will make it shorter duration for cleaning as a higher reading may cause the lid seal to leak. Have to watch for this!

Yes, am thinking of a third leg and gate valves at the START of each leg, along with a ball valve at the END of each, and a guage on each one.

I am happy with it's operation, I think my expectations were different from reality (again) and it threw me off.

I just want to understand all I can as I have been advising some folks on series vs parallel and do not want to steer them into a ditch.

Thanks again!