Losing water pressure temporarily

[PlumbingNeophyte]

Hello,
I'm on a well system. Last year I installed a new pressure tank and switch. Several months ago I had to install a new water heater. Everything worked fine after both of these installs. Then I noticed that I was getting some discharge from the water heater relief valve. Since this was brand new, I figured the problem was because of thermal expansion. So, I installed a thermal expansion tank. Now, I'm temporarily losing water pressure (2-15 seconds) when faucets are open. It seems to only happen when two things are pulling water at the same time (e.g. toilet and sink). I've checked the pressure tank and switch. Both are fine. Could the thermal expansion tank install be causing this? If so, how?
Also, I'm still getting some discharge at the heater relief valve, although much less than before. Any thoughts as to why?

I'm still trying to learn as much as I can and appreciate the help.

Thank you.

 

[Reach4]

Check for a clogged nipple to the pressure switch, slowing the pressure switch response.

The thermal expansion tank should not have been necessary with a pump pressure tank, unless you had a check valve in a very unusual place.

Maybe post a photo showing your above-ground pump, pressure switch, pressure tank, check valves if present.

Another possibility is that the start capacitor for the pump is failing, but that should not correlate with using a higher flow of water.

Now, I'm temporarily losing water pressure (2-15 seconds) when faucets are open.

Had you said for 0.2 seconds, I would suspect your air precharge was too high.

 

[Sponsor]

 

[Valveman]

Look at your pressure gauge. If the pressure is high the pressure relief valve should be leaking water. If the pressure is not high, the pressure relief valve may need replacing.

 

[PlumbingNeophyte]

Sorry for the slow reply. I'm pretty busy with work and have four kids under 5. The nipple to the pressure switch was clogged. I cleaned it out and haven't had a problem since. I was still getting a bit of leaking around relief valve. So I went ahead and put a new one on. That hasn't been an issue since replacing.
Thank you valveman and Reach4 for your time and input. I appreciate it greatly.