How to repair a Weil McLain CG Gas boiler
Click on This thumb nail to see a larger picture of this Weil McLain
Boiler that I made repairs to.
This May look familiar to you If you have an older Weil McLain Boiler.
In the following pictures I will show How I made the repairs to this Boiler. The Call was No heat in the upper zones. When I arrived I found the boiler hot and The pilot light on.
I also noticed that the pump was working. All of the zone valves were in working order and were open.
The boiler was working normal. So I checked the gauge and found there was no pressure in the boiler.
Why was there no pressure in the boiler? This Boiler has a filtrol expansion tank and fill valve. the tank and fill valve work together to keep the pressure in the boiler. The pressure should be between 12 and 20 PSI.
So I checked the pressure in the expansion tank (the gray tank between the boiler and the water heater) I found it had no pressure, so now I know the tank is bad and needs to be replaced. but just to be sure I pumped some air into the tank, and as soon as I did water started to go into the boiler, I could have just pumped it up to 12 pounds and called it a day, But it would not have lasted long and it would have failed again. And once water was added to the system the leaks showed up. So now I will show you the rest of the pictures and explain what I did to solve this problem.
This is a picture of the tank and the pump I used to pump it up. Before you start with this project. Stop and Think About what it is worth to you and how much money it saved you. And make a donation to this web site. Thanks
and the one on the supply side and the Auto vent leaked from the top and would
So now I have 3 leaks and a bad Expansion tank. you may have noticed that
the expansion tank is stuck behind some pipes and is between the boiler and the water
heater, This is never fun.
and the one on the supply side and the Auto vent leaked from the top and would not stop. So now I have 3 leaks and a bad Expansion tank. you may have noticed that the expansion tank is stuck behind some pipes and is between the boiler and the water heater, This is never fun.
Oh Great even with the fill valve removed and the handle for the boiler drain
gone the tank will still not fit between the pipes. I can not remove this tank,
And I can't get the new one back there either.
So not A new and better plan.
So I stand the old tank up and push it back out of the way. (it will stay there till the boiler or the water heater heater is replaced) now with some 1/2" black nipples and fittings I run the pipes in a different direction, facing the front of the boiler
I install the new filtrol fill valve (this comes with the new Tank) by the way this is a 110 filtrol If you need to buy this, It looks like the # 30 expansion tank, But it is different and they are not interchangeable. Then I tie the copper line into the new fill valve.
Then I screw the new tank on to the fill valve. Now if it has to be replaced in the future, it's right there in the open, like it should have been in the first place. Now I put in the new auto vent. and turn the water back on.
But I do not turn the power back on yet because the system is full of air and needs to be purged.
This is a picture of the return side of the boiler. I have opened all the zone valves manually and turned all of the red valves off. I hooked the hose to each of them one at a time and opened the boiler drain about half way (you don't want to let it run out faster then it goes in)
What I like to do is put the other end of the hose into some kind of clear bucket so I can see the air coming out of the lines and I let the water continue to run till I don't see air bubbles coming up from the bottom of the bucket. After this has been done to all the zones. Put the hose on the highest boiler drain or the one furthest from the pump. start letting the water run from the boiler drain then open the red valve ( yours may not be red) and then close the zone valves and let that run till there is no more air. Now you can open all the valves and turn the power to the boiler back on. Find a local Plumbing and Heating contractor