QUESTION FROM bella

We have Electric Hot Water Baseboards, 2 Zones, we recently replaced the Zone Valve and Motor for the main floor because it was sticking open. The new Zone Valve is installed with the arrow going with the flow of the water. We bled the system and have had a little bit of air come out of the bleeder on the top of the furnace but not a lot. Our Baseboards for this Zone seem to rattle/bang almost every time the thermostat stops calling for heat. Any idea what else would cause this?

ANSWER FROM HOME-WIZARD

Dear Bella:

From what you described, it could be two things: 1) The new zone valve that was just installed could be defective. 2) Since the noise that you hear in your pipes is when your baseboard heating system turns off, then it is possible that the expansion tank on your system has gotten filled with water, and there is no longer any air in the tank to provide a "cushion". As such, when the circulation pump turns off and the valves slam shut, you could be getting a "water hammer" effect which gives you the rattling/banging sound. If this is the problem, then you can fix this by draining the water out of your expansion tank, and allowing it to fill with air. To do this, shut off your furnace/boiler. Shut the valve that connects your expansion tank to your system, and then open the drain valve to drain the tank into a bucket (or with a hose to a floor drain or outside). BE CAREFUL, as this water can be scalding hot. Then close the drain valve, open the valve you closed to isolate the tank, and then turn your furnace/boiler back on. Hopefully this will eliminate the banging noise that you have been hearing when the system shuts off. If not, just let us know, and we'll try to diagnose the problem further for you.

Hope this is helpful.
Home-Wizard.com

FOLLOW-UP FROM Bella

Thanks for your quick response, The expansion tank is empty. We contacted the plumbing company that we purchased the Zone valve from and they said that they've never heard of our problem or had a Zone valve come back, and that if it's opening and closing it's working and they won't replace it. He said that we might try closing the water off some so the velocity is less; we tried this but it didn't help. I've read on forums about people having this issue and they have removed one of the two springs from inside the zone valve and that this has caused the valve to close slower and cured the issue, would you recommend trying this?

Thanks again

ANSWER FROM HOME-WIZARD

Bella:

If you are sure that the zone valve has been installed in the right direction, then yes, you can try removing one of the springs, which should allow your new valve to close slower. Hopefully this will eliminate the water hammer "banging" noise that you are hearing when the valve closes.

Hope this is helpful.
Home-Wizard.com

FOLLOW-UP FROM Bella

I am sure it's installed in the correct direction (arrow with the flow of water, same as the upstairs Zone which we have no problems with), unfortunately my husband just looked and there are no springs in the new valve; just gears...

Thanks

ANSWER FROM HOME-WIZARD

Bella:

One option for you would be to replace your zone valve with something like a Taco "slow closing" zone valve. I know this is probably not what you wanted to hear, since you just bought a new valve. But other options such as installing a water hammer arrestor, or relocating your zone valve to say a return line, would likely be more expensive. Not being able to physically see and hear your system makes it hard to say specifically.

Hope this is helpful.
Home-Wizard.com