Home>Discussions>INSULATION & HVAC>Replacing water in the boiler
3 posts / 0 new
Last post
sclowry
Replacing water in the boiler

I had a leaky seal that I replaced on my recirculator pump. I drained the water from my system and everything went pretty well. There is no leak anymore and the pump works fine. The issue I have is filling the system back up with water. I open the cold water supply valve and filled the system. When I did that the pressure relief valve popped due to the high water pressure. It released a lot of water. Now that I am using the system, I hear the water filling my baseboard units every time the pump comes on. I replaced the pressure relief valve with a new one. Should I simply bleed the air out of my baseboard units? How do I know if there is enough water in the system?

Any info is appreciated.

NashuaTech
Re: Replacing water in the boiler

Yes, when you drained the system & replaced the pump seal, you introduced some air into the system.

This is what you're hearing sloshing around in there---start with the HIGHEST baseboards and bleed them first---air in piping will always gravitate to the highest point in the system---bleed them first with the system off.

You should hear air escaping as you open the little bleed valve, then a small stream of water---hold a cup under the valve (or a wad of paper toweling) to prevent wetting the flooring.

The valve at the boiler that lets in fresh water (usually automatically) from the main supply is known as a Pressure Reducing Valve, and is set to allow approx. 12 psi of water into the system---keep an eye on the boiler gauge---it should read ~12 psi when the system is cold or warm and up to ~20 psi when the system is heating up---the relief valve that you found out about with water dumped on the floor is designed to open at 30 psi as a safety valve to protect the system from too much water pressure.

sclowry
Re: Replacing water in the boiler

That did the trick. Thanks for your help.

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.