We moved into a house 2 years ago that has hot water baseboard heat. The boiler is 5-7 years old. It has an Extrol #30 expansion tank on it. The problem is water coming out of the air valve on top. This must have been a problem with the previous owners because the tank is all rusted along with the air scoop. There is a bucket underneath to catch the water. You can hear air escaping and the water dripping out. Can this type of job be done by a do it your selfer? How hard is it to do?

 

Whats the psi on that boiler?? If just the expansion tank yes you can do it. Turn the water off to the boiler drain it down to no psi. And put a new tank on there . Now it should be full of water and very heavy. Turn the auto fill back on. might have to bleed the baseboards

 

PSI is 11 or 12

 

How do you bleed the baseboards? Our other system is steam, I know nothing about hot water. Thanks

 

How do you bleed the baseboards
You have to look around on the baseboard and see if you have them. Small valve some you open with a screw driver

 

Which air valve is leaking?? The shraeder valve on the expansion tank?? Or, the air vent valve on top of the air eliminator?

I don't see how the expansion tank can leak through the valve unless the bladder and valve are both leaking?? Post a photo. BTW, those tanks hold about 4 gallons of water when the bladder fails, they are heavy!

Pete

 

Leon, please clarify something... you are saying that the water is coming from the air valve on top of the tank ??? or ...

are you saying that water is coming out of the air valve on top of the air scoop ???

isn't your tank hanging upside down below the air scoop ?

and there is another air vent on top of the scoop ?

Ed may be correct that your tank is shot if you are leaking water from the air valve on it, there should never be any water coming out of the tank valve, but if it's leaking from the _other_ air valve, then your tank may well be OK ...

got any pics ???

C/YA!
Jeff
"... I'm up on a tightwire ... "

 

On top of the tank is the air scoop, above that is the air vent. That is where the water is dripping out of. It runs down the scoop and the tank to the floor into a bucket.
At night I can hear the air releasing, like on steam radiators, then water drips. The air will come out even with the boiler off.

 

A continuous leak is adding fresh water to the system, and it could cause a lot of damage over time to a closed loop system. The air should have been purged once the system is up and running. Is the air coming from the fresh water being added to the system because of the leak? Your boiler will rust out if this continues.

 

In that case, the tank is probly OK.

The air vent you are talking about has a float in it, sorta like yer toilet (or perhaps more like a float in a carburetor) and a valve that is supposed to close when the air is let out and the float comes up.

It is a pretty easy thing to change. You most likely need to close the supply valve, drain the pressure from the system, unscrew the old one and screw in the new one. {I say "most likely" because there is a fitting available that can be installed between the air scoop and the vent device that closes when you unscrew the vent. You still get a little bit of water but no big deal. Most installs do NOT have these though...} You don't need to let much water out, just enough to release the pressure, then unscrew the old one, and QUICKLY screw the new one in. Leave the bucket in place until you are done, you will get a little water. It could be HOT! so best to let the boiler cool before doing this! Turn the supply valve back on, check for leaks, and you should be good to go.

You will also need to identify whether your old vent has 1/4" or 1/8" threads before you purchase the new. (google "Maid-0-Mist" for one manufacturer, there are several others...)

BTW, if you are lucky, you may not have to bleed the baseboards. If it's piped properly, the automatic air vent will do it for you.

Got any pics ?

-

 

Thanks guys. Now I know what to do.
Eileen