Hey there! I'm new to this forum and need some help. When I turn on hot water, the pressure is good for about 4 seconds then greatly reduces to about 50%. I then hear the water tank trying to fill. I disconnected the cold and tested pressure and it seems fine from the source. I noticed on the cold intake there is this check valve? (pics attached) When I disconnected it the "post" was tilted to the side. I thought this was the culprit so I straightened the "post" thinking the water would flow through better. I noticed slight improvement but not enough to consider it fixed. It seems like the cold is not displacing the hot water at a workable rate. What else can i do? can this check valve be removed?

Thanks in advance for any help.

 

In order to propertly diagnose this you would need to install a pressure gauge in the cold water line at the hw tank.
You are only guessing that the restriction is at the check valve and would need the guage to confirm that.
If the check valve is the problem the pressure will stay up on the guage while the hw pressure drops.

 

More often than not problems like yours are caused by partial clogs downstream of the water heater. The heating forces minerals to precipitate out of the water. These chunks can flow downstream and get caught in shutoff valves and fittings like T's and 90's. This will cause the same symptom you describe where you have good pressure for a few seconds then it trails off to lower flow.

If you test this with a pressure gauge all pressure readings will be the same when no water is flowing. You will only see a lower pressure reading if the gauge is installed downstream of the restriction AND water is flowing.