air source heat pump problem

[chris_cronin]

Recently notice a drop in performance of one of my heat pumps used for heating hot water.
The normal temp rise through the HP is around 8 degrees C but has recently dropped to around 3 degrees C.
The pressure guage shows approx 100psi with the HP OFF rising to approx with the HP ON but I don't know what the pressures should be but maybe these figures suggest adequate refrigerant in the system??
When I compare the 2 HP's when they are both running there is a noticable difference, namely:-

HP 1 condenser temp = 0 degrees C HP 2 condenser temp = 36 degrees C !!

other temps are:

HP 1 compressor out temp = 44 degrees C HP 2 compressor out temp = 46 degrees C
HP 1 NTC temp probe = 38 degrees C HP 2 NTC temp probe = 37 degrees C

Any suggestions?

 

[Leesparkykent]

manufacturer?

 

[chris_cronin]

Trianco Activair S500 5kW

 

[Marvo]

Recently notice a drop in performance of one of my heat pumps used for heating hot water.
The normal temp rise through the HP is around 8 degrees C but has recently dropped to around 3 degrees C.
The pressure guage shows approx 100psi with the HP OFF rising to approx with the HP ON but I don't know what the pressures should be but maybe these figures suggest adequate refrigerant in the system??

I'm not sure what the pressure gauge indicates, maybe you can attach a few pictures.

When I compare the 2 HP's when they are both running there is a noticable difference, namely:-

HP 1 condenser temp = 0 degrees C HP 2 condenser temp = 36 degrees C !!

other temps are:

HP 1 compressor out temp = 44 degrees C HP 2 compressor out temp = 46 degrees C
HP 1 NTC temp probe = 38 degrees C HP 2 NTC temp probe = 37 degrees C

Any suggestions?

The condenser temp of HP1 doesn't sound right, I don't see how it could possibly be condensing at 0C. Has the unit ever thrown any error codes? Have you tried shutting it down for maybe an hour and see if it runs any better when restarted? Have you checked all the obvious stuff such as are the air fans and water pumps all running? Is there signs of oil around any of the refrigeration pipe/flare nut connections?

I don't think it sounds like a power problem so I'm not sure how much help an electrical forum is going to be in this case. I think it's far more likely it's a refrigeration of water issue.

 

[chris_cronin]

There was an ommission in the original text

'The pressure guage shows approx 100psi with the HP OFF rising to approx with the HP ON'

head pressure of approx 250psi with HP running.

I also think there is a typo in the Activair manual. Since HP 1 is working OK I think 'HP 1 condenser temp' should be 'HP 1 evaporator temp' ie the 'cold' coil of HP 2 is NOT cold unlike HP 1 which is!

The reason I posted this on the forum is because information on air source heat pumps is scarce making troubleshooting tricky



LH pic HP 2 OFF. RH ON