Odd Hayward Heat Pump Issue - Stays Running When Pump Is Off


Jul 21, 2013
I have a 2011 era hp21404t model Hayward heat pump. I've noticed that the unit does not shut itself off when the pool pump shuts off. I checked tonight and it's displaying the HP error code and I have to set the thermostat all the way down to OFF to have the unit turn off.

All of the troubleshooting steps indicate it is usually linked to a water flow problem, however my issue seems to be the reverse as the usual issue is that even though water is flowing, the unit will not kick on. In my case there is no longer any water flow, but the unit seems to be unaware of this and continues running.

I'm guessing this is a faulty pressure switch, but before I go down that road, want to see if anyone else has seen a similar issue with Hayward heat pumps?