Air gurgling in radiant heat system

I he mentioned pressure drops when the circ runs, but it looks to be pumping way

from 10 psi to 0-5 psi. 

The picture with 10 psi was taken today. This was the system being on stand by.

I Have seen and taken pictures of this pattern everyday for past 5 days. When system calls for heat it goes as low as 0 and when it goes to standby it goes back to 10

5 psi static pressure is too low, if you have a cold water feed (pressure regulating valve) increase the static pressure to 12-15 psi. It also means that the Ex-tank air pressure must be the same pressure as the fill valve pressure. You have a small Ex-tank so you have very little tank acceptance of heated water, so the air cushion pressure must match the fill valve pressure or else the tank's air cushion will be depressed and the heated water acceptance will be less. This could cause a discharge out the Pressure Relief Valve (PRV). I was looking for a PRV in your photos, but I couldn't see one. You should have two PRVs unless you are heating with domestic water, (not). One on the domestic water supply side of the heater and one on the house radiant heating side.

It appears to me that you are heating with domestic hot water? This is not the way that the sys should be set up. Unless there is a heat exchanger in the tank for the space heating and what I see is that there isn't one. There needs to be one to separate space heating from domestic hot water heating. So, you would only have one Temperature/Pressure relief valve on the tank.

Pay attention to the heat exchanger, which is external to the heater. You don't appear to have one. You have a blended sys. This creates a lot of problems. This is similar to the Radiantec/Polaris setup. This NEGATES much of what I have written so far. Your sys has to be redesigned, I think. If this is a sys without a heat exchanger then only one EX-tank is needed which is on the water heater. Pressure in the heating sys would be the pressure of the domestic cold water supply to the Bradford/White which is usually at 50 psi and then the Ex-tank air charge would be 50 psi. Look to the installation diagram and follow that, which means a heat exchanger and all the necessary products for a separated sys.

"…I was told was not working but they didn't tell me it was urgent to replace if that…" What they were alluding to was that there might not be a spring loaded check valve on the cold water supply between the cold water shutoff valve and the Ex-tank, which is the only reason that one would want an Ex-tank on the water heater.

So you can't show us a rusted hydronic tank caused solely by non-barrier pex tubing? Why make a claim that you know is bogus? Dropping the pressure to 12 in a bladder/tank designed for 30+ will cause the diaphragm to bind, as it is physically larger than the diaphragm in a hydronic tank designed for 12 psi and will now have overlap- but you already knew that.

Groundup, Whaaat??? I have never heard that before. You learn something new every day, which is why I like this site. In fact, I'm learning so much everyday, I'm beginning to think I don't know anything.

@hot_rod you're welcome to share irrelevant "information" all you want, but you and I both know it's not always pertinent to the real world. I have seen you note that a 300ft loop of 1/2" will never exceed maybe .75GPM, even though the pressure drop charts and pump curves we reference every day clearly show a flow approaching double that with a basic 007/15-58 variety circ. *Case in point.* Amtrol and other manufacturers build what they think will sell. Period. When there's an improper air charge in any expansion tank, what happens? The bladder sticks to the steel in the tank or binds on the weld and the bladder will tear. Anybody in the field has seen it a hundred times. I myself have seen torn bladders in exactly the scenario you suggest is perfect, several times now and one of which only a few weeks back- had I known this would end up being a topic of discussion, I'd have documented it to share my findings with the powers that be and better rid the world of poor information. I have also seen many an otherwise closed system, aside from the non-barrier pex, 20+ years old with a hydronic expansion tank and plenty of other ferrous components that still look great inside. Notice I never said or even suggested that o2 ingress doesn't shorten a steel tank's life? I said that dropping the pressure in a potable tank will shorten the tank's lifespan a whole lot more than non-barrier pex will shorten a hydronic tank's lifespan. Big difference. Yes, this is a technicality, but I will not sit idly by and watch a role model for a good portion of this trade publicly share information that I know is false.

the pvc glued to abs just caught my attention. and vented out with abs pipe? isnt all abs pipe foam core?

Those viewers are looking to guys like you, pioneers of the trade, for factual information- not a theory. Most are trying to learn the proper way to install these systems and don't have the luxury of field experience. When you propose your theory as a false fact, those individuls have no way of knowing it's false or what's relevant, and therefore the trade will continue to be half-asked based on poor information from those who are supposed to be helping. I've shared my proof of non-barrier tubing not being the problem that you say it is, where is your proof to the contrary? It's okay to accept ideas that you didn't come up with on your own, you know.

Just got off the phone with the tank people, I stand by my comments, pics and quotes from their trainers.

I did learn that they dimple the diaphrams to prevent them from sticking when tanks are over filled, but it is mostly a well tank issue.

The only limitation on using a ThermTrol DHW expansion tank on hydronics, once the pressure is adjusted, would be the 200° temperature limitation compared to 240° on hydronic tanks.

This is due to the poly liner used on the domestic tanks, which is not unlike the the RadiantPro hydronic tank which has a 200° rating because of the poly liner protecting the steel vessel. The basic differance beetween the RadiantPro and Thermtrol is nipple size, as I suspected from the literature.

I actually have a small well tank, WellTrol as an expansion tank on my hydronic system. The difference from hydronic tanks it has NSF rating.

Your one tank that is not leaking really proves nothing IMO. Low temperature operation minimizes O2 ingress. I've like many otherd have had tanks fail in under 1 year on high temperature non barrier rubber tube systems, much higher O2 ingress at 180°F.

We're not talking about high temp OR rubber tube here, are we? Again, it's okay to be wrong sometimes Bob. This is how we learn. You can choose to accept and learn from this, or you can continue to give out poor information. I think everybody would prefer the prior.

Why always a chip on the shoulder @GroundUp

I come to the discussion with actual data, factory input and confirmation. You come with mere hearsay.

Lets start with a softball, explain this statement of yours?

I said that dropping the pressure in a potable tank will shorten the tank's lifespan a whole lot more than non-barrier pex will shorten a hydronic tank's lifespan. 

The only difference between these tanks is the stainless nipple and the plastic liner on the potable tank. Dimensions are the same, the same shells, same sized diaphram is installed in the same location. The potable tank has the extra protection of the plastic liner, same as the RadiantPro tank for non barrier tunbe systems, in the tank, so potable water can be inside a plain steel tank.

If your statment is correct, lowering pressure in a hydronic tank would also shorten its life?

Regardless of the air pressure charge in any tank, 5 psi or 50psi, the diaphram is pushed against the nipple until the system pressure increases above the air charge pressure. Heating the fluid, thermal expansion caused pressure increase allows fluid to enter a tank.

And no 12 psi on the water side will not allow water to enter a tank charged at the exact same 12 psi air side as you claimed but never explained? The diaphram is against the nipple, still.

Back to the beginning. gasp. "… for manifold they blamed lost pressure and air on it. Is there a reason
to hold off? Also anything I can do like caulk, or tape etc to make
sure water doesn't leak?"

Yes, clean the joint on the manifold and sand the joint with emery cloth. nice and clean and roughed up. with the heating sys off put JB-Weld on the leaking joint and keep the heating sys off for 24 hrs. You can do that first before replacing the manifold. I very much doubt that you are pulling air into the sys thru that leak. Not possible.

moemah123, commenting more is beating a dead horse. Every possible question you have has been addressed. BUT…to condense your concerns…

1. Gurgling in a sys can be caused by more than air. Your Techs have told you that you have a space heating sys and a domestic hot water sys which would have to be separated one from the other with a heat exchanger. No heat exchanger, then, one sys not two. If two sys you need two pressure relief valves, one on the tank (T&P) and one on the space heating sys (30 psi). If two sys you need a method of filling water in the space heating sys. If two sys you need an air eliminator to remove as much entrained air from the space heating fill water as possible. Purging, so the pump can flow water thru the piping sys, removes air pockets while filling the sys with entrained air.

2. Pressure variations. A fall in static pressure in a closed sys indicates a leak of water out of the sys. The speed of the pressure decline indicates the volume of flow lost. The fall in pressure would eventually go to zero and stay at zero until more water is added to the sys.

Pumping into a pressure gauge will increase the gauge reading over static pressure reading.

I give up I can't get this comment box to work like the old comment box.