Pressure drop after installing Bladder tanks

goosegunner · Oct 24, 2014

On Wednesday I changed from my Air compression expansion tank to Bladder tanks. I set the tanks at 12psi ran water into the system with my auto fill and bled some air and then shut off the auto fill.

I did a burn and built ran the storage up to 182/158 I was sitting at 22psi. I went to work my 24 hour shift yesterday and the storage was used to heat the house.

I came home today and found the tank at 144/120 and the pressure in the system was 0.

I checked the bladder tanks and they are at 17psi so some water must be sitting on the top of bladders.

I turned on auto fill and it ran for maybe 20 seconds. Went back to boiler and bled air from the piping and storage tank.

I can see no visible water leaks.

So what do you think, was there trapped air in the system or bigger problem?

gg

velvetfoot · Oct 24, 2014

I'd vote for air. Maybe it got separated out and vented. If it didn't vent, there would still be pressure, whether air or water.
Maybe it would've been good if you left that autofill valve on for a few days or something. Why don't you like to leave it on?

goosegunner · Oct 24, 2014

velvetfoot said:
I'd vote for air. Maybe it got separated out and vented. If it didn't vent, there would still be pressure, whether air or water.
Maybe it would've been good if you left that autofill valve on for a few days or something. Why don't you like to leave it on?

I shut it off because I wasn't sure where my final pressure would end up. With it on my system was at 14psi and my storage temp was 68. Now that storage is a little warmer I should be fine for expansion capacity. As long as the tanks are good.

gg

goosegunner · Oct 24, 2014

Seems odd to me that the bladder tanks are at 17psi now but system was zero. They are floor model, top connection with air schraeder valve on bottom. No water comes out of air valve when depressed.

I would think the bladder would push all water back out and be at 12psi.

gg

maple1 · Oct 24, 2014

What were your temps when you first set your 12psi - before you started heating storage up?

Does sound odd - only thing I think of was the 12psi of air was when cold, and it increased to 17 at 140 or whatever. Although, they should have cooled off to a lot below what your storage temps are.

Do you have more than one pressure guage on the system? They can go wonky - although when I had one go wonky, it read high.

goosegunner · Oct 24, 2014

Initial temps

Boiler 64

Tank 68/67

I am running again and there is definitely air in the system. Can hear it as the pumps are running. No visible leaks, where the heck is it coming from.

Do you think it could have always been in the system do to my air compression tank set up?

I have several pressure gauges. They are close enough to be considered equal.

gg

Bob Rohr · Oct 24, 2014

goosegunner said:
Initial temps

Boiler 64

Tank 68/67

I am running again and there is definitely air in the system. Can hear it as the pumps are running. No visible leaks, where the heck is it coming from.

Do you think it could have always been in the system do to my air compression tank set up?

I have several pressure gauges. They are close enough to be considered equal.

gg

Do you have a valve and means to isolate the various zones and purge them with a good fast flow? if the bubbles are large enough that you hear them, you need to flush them with full flow thru that zone. Air purgers get the remaining small air once the system heats and circulates. You should be able to get it "noise=free' before you start the pump or fire the boiler.

goosegunner · Oct 24, 2014

Full flow as in DW pressure?

I have ball valves and some drains but it gets difficult because of the danfoss and water flow. I should have more ways to bleed.

I wish I had some one like Bob Rohr, heaterman or others near by to look at my system and say cut this in here and here. I would gladly pay to have some expert advice.

gg

Bob Rohr · Oct 24, 2014

goosegunner said:
Full flow as in DW pressure?

I have ball valves and some drains but it gets difficult because of the danfoss and water flow. I should have more ways to bleed.

I wish I had some one like Bob Rohr, heaterman or others near by to look at my system and say cut this in here and here. I would gladly pay to have some expert advice.

gg

Usually a couple of these Webstone valves in the proper location will assure a good flow purge. These newest ones purge from either direction, very handy.

I generally purge at 20- 25 psi, unless the boiler is rated and has a higher psi relief valve. 20 psi at full garden hose flow should purge most any piping zone you have.

Or a nice Caleffi AutoFill which will flow 5 gpm with a 30 psi inlet

Where in Wisconsin are you. I get up to our headquarters in Milwaukee and around the state often. I know a handful of savy hydronic guys around the midwest.

Sounds like you are just an air bubble or two away from a functioning and quiet system.

jebatty · Oct 25, 2014

Sorry, Goose. Do you have access to a small utility pump? Fairly easy purging is done with a utility pump and a 5 gallon bucket. Fill the bucket half way or so and then pump from the bucket through the part of the system you want to purge, with the discharge back into the bucket. Run the pump until the air bubbles stop coming out of the discharge, shut off the isolation/purge valves, and move on to the next part of your system.

I've worked with a system installed with minimal valving to shut off or isolate parts of the system. The system has been worked on twice since the install, and each time part of the work was to add isolation/purge/fill valves at strategic points.

maple1 · Oct 25, 2014

I have ball valves on the end of each of my zones, at the return header, with boiler drain valves just in front of them. All I have to do to get rid of air in a zone is make sure my system is up to pressure, turn up the stat for the zone I'm bleeding, close the ball valve, and open the drain valve (with hose attached going to a 5 gallon bucket). Doesn't take long for the air to spit itself all out. My installer put that stuff alll in place on the original install 18 years ago. He also put one of those little bleeder valve thingies with the round black knob at the top of each zone to let air out - but those have never been used since install. They had issues with them leaking a bit on commissioning, so I'm not touching them.

goosegunner · Oct 25, 2014

Bob Rohr said:
Usually a couple of these Webstone valves in the proper location will assure a good flow purge. These newest ones purge from either direction, very handy.

I generally purge at 20- 25 psi, unless the boiler is rated and has a higher psi relief valve. 20 psi at full garden hose flow should purge most any piping zone you have.

Or a nice Caleffi AutoFill which will flow 5 gpm with a 30 psi inlet

Where in Wisconsin are you. I get up to our headquarters in Milwaukee and around the state often. I know a handful of savy hydronic guys around the midwest.

Sounds like you are just an air bubble or two away from a functioning and quiet system.

Thanks Bob

I live in the south central part of the state between Baraboo and Wisconsin Dells. Or in relation to larger city, 50 minutes north of Madison.

I can isolate every thing with ball valves, my problem is adequate areas to let air out. I need to look at that and probably add some boiler drains.

I think this is one problem area I have. The top one on wall is boiler supply which goes about 10' to where my supply circulator is. It has flow check and I have no way of letting air out of that line if air accumulates in the tank.

The lower one on the wall is the load line to the house. At times I can hear air in the pipe. Yesterday when pressure dropped it was bad enough to sound like slow pouring water gurgling.

Here you can see the straight run from pump that goes directly from pump to tank. I do have ball valves on each pipe between boiler and tank and tank and load.

Thanks

gg

Bob Rohr · Oct 25, 2014

goosegunner said:
Thanks Bob

I live in the south central part of the state between Baraboo and Wisconsin Dells. Or in relation to larger city, 50 minutes north of Madison.

I can isolate every thing with ball valves, my problem is adequate areas to let air out. I need to look at that and probably add some boiler drains.

I think this is one problem area I have. The top one on wall is boiler supply which goes about 10' to where my supply circulator is. It has flow check and I have no way of letting air out of that line if air accumulates in the tank.

The lower one on the wall is the load line to the house. At times I can hear air in the pipe. Yesterday when pressure dropped it was bad enough to sound like slow pouring water gurgling.

View attachment 142280

Here you can see the straight run from pump that goes directly from pump to tank. I do have ball valves on each pipe between boiler and tank and tank and load.

View attachment 142281

Thanks

gg

Are you sure that Taco air sep is working? Maybe the float stuck inside or something in the relief port. If the air is passing thru that air sep it should scrub everything out, and be hissing like crazy. Taco claims 100% air removal

But you MUST maintain fill pressure to eliminate all the air. Drop in pressure usually indicates a big air pocket was removed.

Do you have an Autofill (boiler fill) valve to maintain the 12- 15 psi, or a manual fill valve? Sometimes boosting the pressure JUST to remove the air will help squeeze those bubble smaller to shove them along. remember to drop the pressure back down or you "use up" your expansion tank acceptance with over pressure.

Very nice piping work.

leon · Oct 25, 2014

goosegunner said:
Thanks Bob

I live in the south central part of the state between Baraboo and Wisconsin Dells. Or in relation to larger city, 50 minutes north of Madison.

I can isolate every thing with ball valves, my problem is adequate areas to let air out. I need to look at that and probably add some boiler drains.

I think this is one problem area I have. The top one on wall is boiler supply which goes about 10' to where my supply circulator is. It has flow check and I have no way of letting air out of that line if air accumulates in the tank.

The lower one on the wall is the load line to the house. At times I can hear air in the pipe. Yesterday when pressure dropped it was bad enough to sound like slow pouring water gurgling.

View attachment 142280

Here you can see the straight run from pump that goes directly from pump to tank. I do have ball valves on each pipe between boiler and tank and tank and load.

View attachment 142281

Thanks

gg

========================================================================================================

It looks like you could use one spirovent on the elbow coming out of the tank
and that would solve that issue once and for all.

Karl_northwind · Oct 25, 2014

PM'd.

goosegunner · Oct 25, 2014

Bob Rohr said:
Are you sure that Taco air sep is working? Maybe the float stuck inside or something in the relief port. If the air is passing thru that air sep it should scrub everything out, and be hissing like crazy. Taco claims 100% air removal

But you MUST maintain fill pressure to eliminate all the air. Drop in pressure usually indicates a big air pocket was removed.

Do you have an Autofill (boiler fill) valve to maintain the 12- 15 psi, or a manual fill valve? Sometimes boosting the pressure JUST to remove the air will help squeeze those bubble smaller to shove them along. remember to drop the pressure back down or you "use up" your expansion tank acceptance with over pressure.

Very nice piping work.

The air sep is working, I can hear it hiss occasionally when it goes through or if I fill and bleed.

I had closed my auto fill. It is in the basement in a return line which feeds to the bottom of tank.

My fill valve is set at about 13-14 psi. That is why I closed it for my first fire. I wanted to make sure I had enough expansion room coming up from 68 degrees.

Thanks on the compliment on piping work. Credit goes to my dad on that one. Commercial plumber for 40 plus years. No boiler work though, a lot of Hospital work with Medical gas.

See any issues with tank connections?

Pump layout? with distance to T's?

gg

salecker · Oct 26, 2014

jebatty said:
Sorry, Goose. Do you have access to a small utility pump? Fairly easy purging is done with a utility pump and a 5 gallon bucket. Fill the bucket half way or so and then pump from the bucket through the part of the system you want to purge, with the discharge back into the bucket. Run the pump until the air bubbles stop coming out of the discharge, shut off the isolation/purge valves, and move on to the next part of your system.

I've worked with a system installed with minimal valving to shut off or isolate parts of the system. The system has been worked on twice since the install, and each time part of the work was to add isolation/purge/fill valves at strategic points.

Ahh the "magic bucket"
That way has worked for me as well.They guy who designed my system told me how to do that to get rid of air.He called it the "Magic Bucket.
I will be putting it to work today.I have two zones of Cast Iron Rads to fill and purge.
Thomas

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Pressure drop after installing Bladder tanks

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