Heat pump showing low pressure

[Jsangerman]

I had a new Rheem heat pump installed about 2 months ago. Before that, I replaced my single-speed pump with a variable-speed, which I mostly left with the default settings (couple hours high speed, 10 hours low speed, couple more or so at mid-speed).

After installing the heat pump, I adjusted the mid-day speed to the heat pump would run, to 1750 rpm up from 1400. About a month later, I noticed I was getting the low-pressure note on the heat pump, so I adjusted the speed again, all the way to 2100. Now, about a month later, it's giving me the note again, and it won't turn on until I get the speed up past 3000 rpm (max is 3400).

I haven't noticed any other changes, my water level is normal, and I haven't checked water pressure. Any idea what's going on?

 

[ajw22]

Welcome to TFP.

Pool_Medic got it below.

 

[Pool_Medic]

Your heat pump has a flow switch that recognizes the subsequent water flow. VS pumps move water at a slower rate, that slow rate allows filters to capture more debris. As your cartridge or sand filter gets dirty that flow decreases and the flow switch connection fails. Either bump up the speed or clean or backwash more frequently.

 

[Jsangerman]

Your heat pump has a flow switch that recognizes the subsequent water flow. VS pumps move water at a slower rate, that slow rate allows filters to capture more debris. As your cartridge or sand filter gets dirty that flow decreases and the flow switch connection fails. Either bump up the speed or clean or backwash more frequently.

Ahh, that makes sense, and should have been obvious. I'll do a little investigation and see what I can manage there. Thanks.