One radiator stopped heating

Griff235

I bought an old house that has old water radiators heated by a Crown boiler 140000 BTU on the basement. All radiators were working fine until one day the boiler stopped. The plumber came and replaced the transformer for the aquastate control and thermocouple for the gas valve.

Then the system started and most radiators worked but... 1 on each floor didnt. the house has 2 floors.  We tried bleeding them and very rusty water came out so we drained the boiler and kept bleeding the radiators cause water was still coming out too dirty. After doing this, the radiators that were working now stopped working! We bled more and they came back on but... we still have 2 that can't seem to come back on.

The water pressure in the house is somehow low as it has an old water main... not sure if this could be a problem because all radiators were working before.

I am desperate cause I don't know what to do now... should I keep bleeding? Can this be the result of another problem? I have read some posts and some mentione balancing but I didn't understand how to do it...please help!

Paul Pollets

Check out...

You may have several issues: is the pump on the supply header pumping away from the expansion tank? Is the expansion tank waterlogged or charged at the proper pressure if a bladder tank? All boilers have dirty water. Usually a chemical is used to clean the system. Refilling and purging  requires patience and system knowledge. If this is a gravity conversion, you may have an attic expansion tank, which is another story.  If the pump is on the return and you're not pumping away...filling the system is difficult as you will introduce air with the fresh water.