Swimming pool heat pump not performing

[iPlumb.it]

Hi all, posted this one in the wrong category earlier, think its better suited here.

I am a heating engineer that installs heat pumps in domestic homes. A new customer called me the other day regarding his swimming pool heat pump breakdown.

This is the first time I have been called out to a heat pump breakdown, so sorry if I come across as being a novice.

The HP is a Calorex AW510 upon initial inspection everything seems to be working correctly, the pool thermostat cuts on and off, the time delay switch is ok along with the fan and compressor.

The customer has been away for three days so as the property is just up from my road I have left the pump on 24hrs for the three days and have been monitoring the temperatures both on the lines within the HP and the pool.

With the HP thermostat set to maximum I have recorded these temperatures:

Day 1 Day 2 Day 3

HP thermostat: 16c 17c 18c
Line on outlet of compressor: 26c 28c 27.5c
Pool water: 17c 19c 16c

The temperature drop across the condenser/heat exchanger lines are:

Inlet: 27c Outlet: 22c

The unit is charged with R22. Does it sound like the refrigerant my need to be replaced? What is the going rate to recharge a HP?

Thanks in advance for any help/advise

[monkey spanners]

What was the reported fault with the HP?

[al]

Do you mean the discharge pipe from compressor? Those temps are way too low if so, what are your pressures and superheat etc?

al

[Brian_UK]

Do you mean the discharge pipe from compressor? Those temps are way too low if so, what are your pressures and superheat etc?

alOP can't answer that, he doesn't have the tools or know-how.

First thoughts are that it is low on refrigerant or the reversing valve, if fitted, is also iffy.

[install monkey]

check the solonoid valve chances are the seal has perished-discharge line should be hot

[monkey spanners]

Had dirty evaps on few of these, get mold and green stuff growing on them as always damp, think its hot gas bypass rather than rv valve for coil defrost, also often have car aircon style driers with sightgass built in, might give an indication as to charge condition.

You'll need your F-Gas ticket to work on it though...