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Amtrol #30 expansion tank replacement?

11K views 36 replies 9 participants last post by  hvacvegas  
#1 ·
I have a Amtrol #30 expansion tank that I think needs replacement. I am getting quite a bit of water coming from the pressure relief valve that I am catching in a bucket. I checked the pressure of the tank and it reads 12 psi. I think the expansion tank bladder has a hole. When I tap on the tank there is no difference in sound from top to bottom.
My question is:

1) My home is a small ranch with 2 zones. Is 12 psi the correct pressure?
2) Do I have to shut down the furnace and the main water supply and drain the heating system completely before replacing the expansion tank?
3) Is there anything else I should do or know about before attempting this replacement?

I am a bit of a novice when it comes to heating systems but I did successfully replace a Taco circulator with no problem. Any assistance would be appreciated. Thank you
 
#3 ·
When I checked the pressure it was 12 psi which is the pressure this tank comes from the store with. Exactly how much water is in it I'm not sure but it feels warm a little more than 3/4 of the tank. I have purged this system several times since I bought this house, including when I changed the Taco circulator. When I checked the pressure no water came out. By the way, nice rod in your picture.
 
#15 ·
I don't think your boiler pressure is 60 PSI. Can you post a pic of it? Also you can't check the pressure of your tank attached to your system under pressure. It needs to be isolated, the system pressure dropped, or the tank removed.
You could've simply had air in the system, or the feed valve is stuck open, the pressure shot up, blew out the relief valve, and now the relief valve isn't seating. So water drips out, feeder keeps feeding...round and round you go.
Also, I always diagnose pressure problems with a separate 0-30 psi gauge, rather then rely on the boiler gauge.
Like mentioned earlier, get the problem properly diagnosed, before replacing parts/wasting money.
Some tips: if you're draining the system, and it's been a while, change the relief valve. If your replacing the expansion tank, have the tech install a Webstone expansion tank valve. Then in the future you can isolate the tank and check the pressure pretty easily.
 
#17 ·
The expansion tank is 12psi. I also have a gauge on the furnace that tells me the water temp and also has a pressure reading. I will go to the basement tomorrow morning and take a picture of that temp/pressure gauge and send it to this thread. Thanks for responding.
 
#18 ·
Once again, you don't know the what the pressure is on the expansion tank unless it's isolated, or removed from the system. Just putting a pressure gauge on the tank is not accurate.
 
#20 ·
It's really simple!

Watch this video:
https://www.youtube.com/watch?v=WN7bImdkgTM

Then if you still think it's a good idea to mess with the boiler yourself find some DIY site to give you step by step instructions.
 
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#25 ·
Wondered that myself.
Maybe because the big box stores don't sell oddball pipe plug sizes????
 
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#27 ·
60 psi should have that relief flowing like a fire hose.
 
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#28 ·
60 psi should have that relief flowing like a fire hose.[/QUOT

OK, I admit it. I'm an idiot. I read the gauge wrong. My basement is dark and my eyes not good in the dark. Here is a picture of the gauge on my boiler. I read the bottom needle wrong DUH! But I still can't figre ot why so much water is coming from the relief valve.
 

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#32 ·
I think we've gone as far as we can here without breaking the site rules.
Call a technician experianced in hydronic repair and get your system properly diagnosed. There's a million and one things we could guess it could be over the internet.
 
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#35 ·
Thanks STEVEusaPA. I was so caught up in this whole thing I forgot about that great advice. I will start by replacing the relief valve and if it is still leaking I'll call a professional. Thank you for your helpful tips. I'll let you know how it turns out.
 
#36 ·
What size is correct for your boiler? Is the current safety sized correctly?
 
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