Can a water heater and air conditioner use the same drain?
Wednesday, August 19, 2020
Combining the water heater and a/c drains is not allowed by the International Residential Code (IRC) and the Residential Edition of the Florida Building Code [FBC P2804.6.1(4)]: "The discharge piping serving a pressure-relief valve, temperature-relief valve or combination valve shall serve a single relief device and shall not connect to piping serving any other relief device or equipment."
One of the worst examples of combining the water heater TPR drain with the air conditioning condensate drain that we saw a few years ago was a condensate drain that terminated into the catch pan and drain of a water heater located below it. The water heater catch pan is not meant to have water dripping into it continuously and, as a result, the base of the water heater was badly corroded. Don’t do it.
To learn more about the TPR drain from a water heater, see our blog post What are the code requirements for the discharge piping from a Temperature-Pressure Relief (TPR) valve at a water heater?
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To learn more about heating and air conditioning systems, see these other blog posts:
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