Heat pump will not kick on.  It is an older Hayward Heat Pro (analog).  It is getting power and when I turn the knob to select temperature, it makes a clicking sound like it is engaging but nothing happens.  Is there a way I can bypass the water flow switch to see if it is bad?  Any suggestions on what part may be bad? 

Marc Miller
Thank you for writing Mike. Clicking usually means the heater is off on some safety switch like the water flow switch, freon high pressure switch, freon low pressure control, the time delay relay or maybe the compressor contactor is bad. It possible could even be a thermostat as I have seen ants get into those and they still click but the ants stop the electric flow. There could also be some bad wires. Mice like to chew on them over the winter sometimes.
Some of the reasons might not be a part failure and might be related to not enough water flow. I have seen many time especially when people make bypass assemblies that even though the water valve looks open it has failed closed inside the pipe or else the valves are in the wrong position. Clogged pool water filters don't help too. I would suggest you get an A/C heating service guy to trouble shoot what electrically is keeping the heater off. It shouldn't take somebody good more then 15 minutes to get to the bottom of this. I am not a big fan of bypassing controls.
Please let us know what it turns out to be.
We don't have many issues with that brand.
Best Regards,
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