Why is the water from my heat pump lukewarm?

If your water is lukewarm, not hot, this is often due to an issue with the tempering valve. A good test is if you can have a shower only using the hot tap and the water is still only lukewarm.

To test the tempering valve, place a bucket under the overflow pipe and release the valve. If the water that comes out is hotter than the water in the house, it’s likely due to a failed tempering valve. If your system is still set to a maximum of 60^oC (the installation default) then you shouldn’t be concerned about getting burned during this test.

Note that older electric storage hot water systems didn’t require a tempering valve so you may be used to water hotter than the set max of 60^oC.

Tempering valves are a consumable part not covered under warranty as the water conditions across Australia vary, however, be assured that any plumber can replace a tempering valve.