HP6002 Heat Pump - High Pressure

[Pappy]

Have you had the unit serviced recently? Overcharging can cause this. The fact that it's kicking out in 5 seconds kind of leads me to believe what you have is a pressure switch failure.
On any heat pump, the most common cause of high pressure is debris clogging the condenser. On a pool heat pump it may be called something else. Can you backwash, or reverse the flow through the heat pump? Have you had a filter failure that would allow gunk to get to it? Scale build-up will also reduce heat transfer, but wouldn't happen suddenly. It would start out by running several minutes, then cycling off and coming back on in a minute or two.

[PoolDoc]

It may be a Hayward HeatPro, but I'm not sure.