Water pressure dropping off

[Dirtmover]

My setup: pump -> pressure switch (40:60) -> tank -> sediment filter -> softener

Been noticing the water pressure/flow drops considerably more than it used to when the pump is not running and the pressure tank is emptying. Everything is fine while the pump is running. The drop is noticed on both hot and cold and also, to a slightly lesser degree, when the filter and softener are in bypass.

I've not checked the pre-charge on the pressure tank yet, though I did replace it 5 years ago and set it to 38psi at that point. I'll check this tonight but could loss of charge in the tank cause this symptom? Anything else I should check?

 

[Valveman]

Pressure is always lower when the water is coming from the tank. The pressure has to drop from 60 to 40 before the pump comes on, which is a loss of 33% of your pressure. But a 40/60 switch is a 40/60 switch. You shouldn't see the pressure get any lower than 40, no matter how much air you have in the tank. If the tank was waterlogged and the pressure switch was kicking the pump on and off rapidly, it would seem like lower pressure than it really is. But that is the opposite problem from your description.

 

[Sponsor]

 

[Dirtmover]

Good point about it not going below 40psi and the gauge does indeed confirm that the pump kicks in at the correct point.

The pump cycles as I would expect, for example, when I take a shower the tank draws down for the first few minutes to a point where the flow is quite pitiful which makes for a frustrating experience. Once the pump kicks in the flow returns to a much more acceptable level and the csv saves the day by keeping the pump running for the remainder of the shower.

I'm guessing I have a restriction somewhere in my plumbing, but where to start tracking this down?

 

[Reach4]

'm guessing I have a restriction somewhere in my plumbing, but where to start tracking this down?

-> sediment filter ->

This would be the leading candidate.

For further troubleshooting, consider where you can mount a garden-hose thread pressure gauge for diagnosis. Laundry taps, WH drain, outside hose bib.

 

[Dirtmover]

Bypassing the sediment filter makes a very small difference.

I can put a pressure gauge at all of the places you suggest but not quite sure how to use it. With no water flowing it will read the same as the gauge on the tank tee even if there is a restriction somewhere.

 

[Reach4]

Bypassing the sediment filter makes a very small difference.

I can put a pressure gauge at all of the places you suggest but not quite sure how to use it. With no water flowing it will read the same as the gauge on the tank tee even if there is a restriction somewhere.

Yes. So as you are looking for pressure drops, you will read the pressures while drawing significant water.

If you are looking at each side of a 100 KOhm resistor measured to a reference such as ground, the voltage will be the same if there is no current flowing.

 

[Dirtmover]

Turns out the gate valve after the pressure tank was seized and was only about 1/2 open but had become pretty badly fouled with iron deposits over time to the point where I could only see a very small opening through it. That valve is superfluous so I got rid of it altogether.