Bleeding Gravity Hot Water System

Bob Tescione

Hello;
I tried to bleed my radiators last night and found that the radiators on the second floor of my 2 1/2 story 1908 house didnt want to bleed. I got some air out of one of the radiators, but no water emerged from any of the radiators on the second floor. Water did bleed out of the first floor radiators.

Am I doing something wrong?

Thanks for any help you may be able to give.

Bob

zeb_3

pressure ?

sounds like you are trying to remove air and not putting water in its place. Do you have an automatic fill valve, is a valve closed on the make up line?

Bob Tescione

Thanks for your hint, Zeb. I just checked in the basement and traced the water lines and the valves all seem to be open. I dont remember if I mentioned that this is a gravity system and since Ive been living here (27 yrs) only the boiler was replaced about 22 yrs ago. This non bleeding problem just started this year when I went to bleed the air out for the start of the heating season. I should also mention that we keep the house fairly cold (64F), so I just turned up the thermostat to see if maybe a higher temp might affect how the water flows--this is my first attempt at trouble-shooting the system.

The diagram at this site shows an expansion tank in the attic. In my house, there is an expansion tank in the basement, chained up between the floor joists. This is what has been here and appears original. There is no circulation pump, although there are what appear to be pressure valves in the system. One has a by-pass line around it.

Thanks
Bob

[Deleted User]

you have to add water to the system

as you are lowering the pressure by bleeding the air. if the valves are all open, then you may have a stuck regulator valve. how many stories tall is your house? this will dictate your boilers water pressure.

Bob Tescione

Gerry: The house is a 2 1/2 story. No radiators in the attic or basement.

Do I by pass the regulator in the line over the boiler (there is a bypass line) to fill the system? I jsut sort of assumed that with the system all hooked up as it is that it would automatically fill as needed.

Thanks for your help
Bob

[Deleted User]

whats your gauge pressure?

should be around 12 or 15 psi. if not, then the regulator may be stuck closed. fill it to the proper pressure through the bypass valve. then close it. you will have to do this each time you bleed radiators. which hopefully is just once every few years, hopefully. most people around here dont bother with the auto fill when it fails, they just manually add water pressure usually just at the beginning of heating season.

Howard

Don't overlook the expansion tank!

Chances are the tank is waterlogged because the air went into your radiators. Drain the expansion tank(so that it fills with air)then add water to the system. If you run a system with no air cushion, the heated water will expand, build up pressure and hopefully trip the relief valve. This lesson was demonstrated to me one time when a technician bled all the radiators but didn't notice the absence of a relief valve or an expansion tank. The dining room radiator burst.
Howard--Chicagoland

Bob Tescione

No gauge that Im aware of. I did bypass the regulator last nite and added water to the system. I was able to then bleed the 2nd floor radiators. It did seem to help when we raised the temp in the house. We have reset it to our normal 64F.

Thank you all for your assistance.

Bob