[hellohello]

Sometimes when taking a shower, I notice that the shower will lose a little pressure and the temperature would get a little cooler, as if somebody were to flush a toilet or turn on a cold water faucet or something. But this happens even when there is nobody else in the house, which baffles me. Also, this is city water (not well water) and this still happens when the washing machine is turned off.

What could cause this?

 

[Bondo]

Sometimes when taking a shower, I notice that the shower will lose a little pressure and the temperature would get a little cooler, as if somebody were to flush a toilet or turn on a cold water faucet or something.

Ayuh,.... It would get Hotter, not colder in that case,....

What sorta heatin' system ya got,..??

What sorta water heater ya got,..??

 

[WhatRnsdownhill]

do you have a wall hung tankless heater?

 

[hellohello]

Ayuh,.... It would get Hotter, not colder in that case,....

What sorta heatin' system ya got,..??

What sorta water heater ya got,..??

You're right, it get's hotter, my mistake. Gas fired boiler and 40-gallon gas fired water heater.

do you have a wall hung tankless heater?

No.

 

[WhatRnsdownhill]

could be a leaky toilet and when it gets low enough in the tank the fill valve opens up..

 

[SeniorSitizen]

I'll take a WAG. You have a pressure reducing valve on the municipal water line and / or a single handle shower control temperature balancing valve.

 

[hellohello]

could be a leaky toilet and when it gets low enough in the tank the fill valve opens up..

Doubt it, I've never noticed the toilet running otherwise.

I'll take a WAG. You have a pressure reducing valve on the municipal water line and / or a single handle shower control temperature balancing valve.

There IS a pressure reducing valve on the municipal water line just as it enters the house. But my understanding is that this would reduce the pressure to a constant pressure, and not fluctuate. And no to the single-handle shower control temperature balancing valve. It's two separate valves - hot and cold.

 

[WhatRnsdownhill]

the PRV could be telling you it needs a cleaning or rebuild, and that is why pressure if fluctuating...

 

[hellohello]

the PRV could be telling you it needs a cleaning or rebuild, and that is why pressure if fluctuating...

Interesting thought, I'll have to look into that.

 

[WhatRnsdownhill]

its a process of elimination to trouble shoot...that would be one of the first places, as you eliminated afew other problem ares by not having them..

 

[jmon]

Agree with others, definitely check out the prv for proper operation, adjustment and cleaning. Take some pressure readings at hose bib with and without a faucet on and post results. Sometimes all they need is a little cleaning and adjustment.

There is a screen on the inlet side that can get clogged with sediment and may affect the way it works. I've seen that before. They don't last forever.

If it's old and needs to be rebuilt, better and easier to replace it, imo.

Please post a picture of the prv and water heater set-up. Thank you.

Hope you get it figured out soon.