Pressure relief valve (Boiler)

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  #1  
Old 05-26-04, 05:05 AM
buytick
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Arrow Pressure relief valve (Boiler)

I have a gas hot water baseboard heating system. The boiler pressure relief valave is leaking. I bought a replacement, but I need step by step instructions to replace it?
 
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Old 05-26-04, 11:44 AM
Ed Imeduc's Avatar
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Wink

Its a lot in just what you have there and can do. You sure that the boiler expansion thank is not water logged?

Is this a pop off and auto fill valve in one ? Do you have a shut off in the water line to it or one past it? Is there a union there in the pipe by it?

Come on back here with some more info and we can help you here.

ED
 
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Old 06-01-04, 04:27 PM
fraumatty
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Smile partial answer to your question

As Ed says there may be more to this. If it's an old system you may have an expansion tank that needs draining. In a normal one or two story home the psi on the tridicator gauge should be about 12 to 18 lbs. Relief valves are preset to leak at a certain psi to prevent dangerous pressure rise in the system. If this is true you need to isolate the expansion tank from the boiler by closing the valve between the tank and the boiler. Then open the drain **** and drain the expansion tank. After draining the expansion tank fully reverse the valves by closing the drain **** and opening the isolation valve between boiler and tank. PSI should equalize at about 12 to 18 lbs depending on what the pressure reducing valve is set at.
If this is a newer system you probably have an X-TROL type tank. A tank with a diaphram that basically does the same thing as an expansion tank that is removing air from the system and helping to maintain even pressure thruout the hydronic loop. If the X-TROL tank is full of water it needs to be replaced. It should only be filled w/ air. Your can test this by opening the bicycle tire like valve on the top. If you depress it and water comes out, the tank is shot.
Lastly, there are other issues involved for example if your boiler has a tankless coil (domestic hot water), it could be leaking into the system and would result in a leaking domestic relief valve. Check it out and get back.
 
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Old 06-04-04, 04:38 AM
buytick
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Relief valve

Thanks for the info. I closed the supply to the expansion tank (big black metal cylinder hanging from rafters) and opened the spigot. it was empty.
closed the valve. now what?
 
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Old 06-04-04, 07:18 AM
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You did open the valve from the boiler to that expansion tank I hope. Now where is this T/P at on the boiler. As I have ask is it all one auto fill and T/P are some thing else?


ED
 
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Old 06-04-04, 03:15 PM
buytick
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prv

I reopened the line to the expansion tank. What are you asking? T/P? what is that? What i need to know is, if I should close the input valve to the furnance, then replace the valve, then what?
 
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Old 06-04-04, 04:07 PM
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Im still not sure what you have . Yes close the water valve to the boiler .Drain it down to no Psi in it . Pull the valve put the new one on turn the water back on and bleed the whole boiler and all base baseboards so there is no air in it.

ED
 
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Old 06-05-04, 03:22 AM
buytick
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Prv

Ed
When you say make sure the Pressure is low, should the furnace be on? I shut the whole thing off about 2 weeks ago, by shutting off the electrical switch. What I think I'll do is what you say. Shut the water feed off, change the valve, turn it back on and bleed the air out. Where do I bleed the air out from? The expansion tank, the relief valve? I know how to bleed it from the radiators. I will do that last, right?
Thanks so much.
 
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Old 06-05-04, 04:35 PM
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Wink

Turn the power off to the boiler. Turn the water off to the boiler. drain the boiler at the boiler drain c** till no pressure in the boiler. Change the pop off. turn water back on. Now bleed all baseboard and R/D in the home.



Ed
 
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Old 06-06-04, 03:45 AM
buytick
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prv

Thank you Ed !!!
 
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