Originally Posted By: kswift This post was automatically imported from our archived forum.
I have read in the codes (I think, ICC) that P/T valves are required on pool/spa heaters. However, I’ve always thought that pools and spas are not closed systems, because the surface of the water permits a release. In other words, it would be like requiring a P/T valve on a kettle, where the steam simply escapes through the spout. What am I missing? And thanks in advance for educating me.
Originally Posted By: John Clayton This post was automatically imported from our archived forum.
A pool/spa system can easily become a “closed” system with such a multitude of appurtenances that can malfunction or inadvertently be closed or turned off. These could include such things as plugged filters, injectors and jets. Inadvertently operated bypass or multi-function valves. Also malfunctioning check valves, electronic or automation valves. These Items may be installed both upstream and downstream of the heater.
Another thing to remember, the temperature pressure relief valve should be rated below the maximum allowed temp/press of everything in the pool/spa system that could be subject to such temperatures or pressures and not just rated for the pool heater itself.
Originally Posted By: jweinberg This post was automatically imported from our archived forum.
kswift wrote:
I have read in the codes (I think, ICC) that P/T valves are required on pool/spa heaters. However, I've always thought that pools and spas are not closed systems, because the surface of the water permits a release. In other words, it would be like requiring a P/T valve on a kettle, where the steam simply escapes through the spout. What am I missing? And thanks in advance for educating me.
Hi Keith,
A TPR valve is required on a pool/spa heater if a shut-off valve exists between the outlet of the heater and the pool or spa. Makes sense since you have a system that is manipulating water into the heater inlet and a valve that may be shut closed after the outlet. Sounds like a ripe situation for overheating and increased pressure. Therefore a TPR valve is required.
There is another device that addresses the issues that John brings up about the system becoming closed. Yuu should check for a flow sensor device inside the heater that senses if water flow in the heater stops and will then shut down the burner to prevent overheating of the pool heater.