I recently installed a Whole House Water Filter - GE GXWH40L.

It works fine, but I noticed that when the filter is ON:
(1) The water heater stars to leak significant amounts of water through the Pressure Relief Valve
(2) There is a distinctive knocking noise when water appliances, washer, dishwasher, even faucets, shut off. Like "hammer effect", but with about 1-2 seconds delay.

If I by-pass the filter, there is no problem with either (1) or (2).

Is there any known issue with such water filters and if yes, what is the solution? Why is it causing this? Will a hammer arrester fix the problem? Where do I place it - in front of the filter?

Thanks!

First, measure pressure on the inside of your house ( past pressure regulator ). Pressure should not be higher than 55 lbs. Then, make sure the filter is installed with the flow. Third, make sure all valves are in OPEN position.

Filter installation should have nothing to do with pressure relieve valve leak. PRV leaks when under too much pressure.

Knocking noise indicates some loose part in your plumbing system. It can be that leaking PRV or water valve you used to close and open water during filter installation. It can also be cartridge inside the filter.

Check those out and let me know what you've found out... Back to you... Milo

Dear SDFG -
I have no answer to this, -but I have the same water filter and the Same things are happening to me - the water hammer and prv leak.
Did you ever get a good answer - I know it is 2 years, later, but am hoping you found out what the problem was, and that you actually look here.
Can you email me, either way -

Thanks
Gene
[email protected]

As soon as I put it on bypass, all the problems went away - very strange

Hi Gene

I believe the GE Whole House Water Filter - GE GXWH40L has a built in check valve. The additon of a check valve effectively closes a previously open system and will not allow thermal expansion of water to flow back out to the city water system and therefore shows up as a drip/leak at your water heater's temperature and pressure relief valve.

To fix this you need to install an EXPANSION TANK to accommodate the expansion of water due to the heating of water from your water heating source.

You will also need to install an electrical GROUND WIRE jumper across the whole house filter to make your home ground continuous. This is very important here, OK?

Glad to discuss more...

Mark

PS: Call GE to confirm the filter has a check valve or backflow preventer