Pressure regulator valve

[DHD]

Just had the PRV changed at our house. Pressure coming into house before PRV is 160. Back of house around 55 to 60. My concern is that a couple of times a day it will spike to 75 - 80 for no apparent reason. It then settles back down to around 55. Today we were gone for 5 or 6 hours, no one else at home and the pressure was at 75, it peaked while gone to 85. Never came back to 55 until I flushed a toilet. I left the pressure gauge on to monitor.

Is this thing working correctly. It's 4 days old.

Thanks

 

[phishfood]

Do you have an expansion tank or expansion valve on your water heater? If not, that is likely the cause of this. Even if you do, the pressure in the system will still tend to rise somewhat.

 

[DHD]

Do you have an expansion tank or expansion valve on your water heater? If not, that is likely the cause of this. Even if you do, the pressure in the system will still tend to rise somewhat.

Yes on the expansion tank. Just concerned that if normal pressure reading averages 52 - 55 and then at some point jumps to 80, is the PRV doing it's job?

 

[phishfood]

When the water heater heats cold water, the water expands. This increases the pressure in the system, since the PRV will stop the pressure from backing out into the main. Without an expansion tank or valve, the pressure can easily build to upwards of 150 PSI. Your expansion tank is absorbing this increase. However, there is likely to be some amount of pressure increase. I think that this is what you are seeing.

See if you can find any relation between the pressure increase and the use of hot water.

 

[DHD]

When the water heater heats cold water, the water expands. This increases the pressure in the system, since the PRV will stop the pressure from backing out into the main. Without an expansion tank or valve, the pressure can easily build to upwards of 150 PSI. Your expansion tank is absorbing this increase. However, there is likely to be some amount of pressure increase. I think that this is what you are seeing.

See if you can find any relation between the pressure increase and the use of hot water.

Yes it appears to correlate around hot water usage (showers, dishwasher, etc.). I'm going to check the pressure in the tank in the next day or so. If I'm maintaing 52 - 55 pressure at the outside spigot, what pressure should the expansion tank be at?

 

[DHD]

Yes it appears to correlate around hot water usage (showers, dishwasher, etc.). I'm going to check the pressure in the tank in the next day or so. If I'm maintaing 52 - 55 pressure at the outside spigot, what pressure should the expansion tank be at?

Just checked and there was no air pressure in expansion tank, no water coming out of schrader valve either. Pumped it up to 45#. Ican see on the pump that air is in when I removed the pump to check again, no air. Went through this several times, same result. The unit is a Watts PET 5. Now what?

 

[johnjh2o]

Replace the tank.

 

[DHD]

Replace the tank.

I spoke with Watts this morning(after I posted) and they said to remove the tank and then fill with air. Tank is filled with water and something about negative pressure in a closed system. The bladder could have drained gradually over time.

 

[johnjh2o]

If you filled the baldder with air then checked it again and there was no air in the balder the bladder is gone and the tank needs to be replaced.