Before and After Water Heater. - Page 3 - Plumbing Zone

ToUtahNow · 01-04-2009, 12:17 AM

A lot of people just assume a thermal expansion tank is needed on all water heaters. Both the IPC and the UPC require a devise to control thermal expansion if a check valve type devise is installed between the water heater and the municipal water (our private) source. Where the UPC differs is when the water source pressure exceeds the relief valve pressure, a means for controlling thermal expansion needs to be installed regardless of whether a check valve was installed or not.

Mark

WestCoastPlumber · 01-04-2009, 01:04 PM

Quote:

Originally Posted by ToUtahNow

A lot of people just assume a thermal expansion tank is needed on all water heaters. Both the IPC and the UPC require a devise to control thermal expansion if a check valve type devise is installed between the water heater and the municipal water (our private) source. Where the UPC differs is when the water source pressure exceeds the relief valve pressure, a means for controlling thermal expansion needs to be installed regardless of whether a check valve was installed or not.

Mark

Good point, I forgot about the excesive water pressure requirement. I don't run into that high of water pressure around here, even by the water tanks in Redondo Beach.

A Good Plumber · 01-04-2009, 05:45 PM

Quote:

Originally Posted by ToUtahNow

A lot of people just assume a thermal expansion tank is needed on all water heaters. Both the IPC and the UPC require a devise to control thermal expansion if a check valve type devise is installed between the water heater and the municipal water (our private) source. Where the UPC differs is when the water source pressure exceeds the relief valve pressure, a means for controlling thermal expansion needs to be installed regardless of whether a check valve was installed or not.

Mark

Utah,
If the water source pressure exceeded the relief valve pressure, it would also exceed 80psi and therefore require a PRV to reduce pressure. Because of the PRV, an expansion tank would be needed.

The assumption that all water heaters need an expansion tank is true only when a PRV, check or other device "closes" the hot water system.

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01-04-2009, 12:17 AM	#21
ToUtahNow Cruise Director Join Date: Jul 2008 Location: California/Nevada/Utah Posts: 2,414 My Photos	A lot of people just assume a thermal expansion tank is needed on all water heaters. Both the IPC and the UPC require a devise to control thermal expansion if a check valve type devise is installed between the water heater and the municipal water (our private) source. Where the UPC differs is when the water source pressure exceeds the relief valve pressure, a means for controlling thermal expansion needs to be installed regardless of whether a check valve was installed or not. Mark