Pool Heat Pump

Hi, was hoping someone could help with an outdoor pool heat pump that is not reaching or maintaining temperature.
For the last 3 weeks the pool has had no cover. At first I thought this was the problem as ambient temperature is between 16-22C day and 8-12 night. But the customer says that pool has never maintained temp even when covered in warmer months.
They have had two of these 60kw heat pumps on two matching pools. The first one lasted only one month before compressor failure. It was replaced with a 50kw unit that seems to be easily reaching temp (with a cover).
Pool is 16m x 8m and holds 160,000lts. Set temp is 27C but is only reaching 21C to 25C depending on ambient temp, sunlight hours and wind.
Do I just have too much heat loss due to evaporation, or another faulty unit? The owner is convinced that the heat pump is at fault and pool is due to close in one week (before cover is repaired).
Heat pump uses 410A refrigerant,
Air on 16.5C
Air off 10.4C
Discharge press 295psi, temp 51C
Suction press 95psi, temp 10.5C
Liquid line temp 26C
Water in 24.5C
Water out 28C
Any help or ideas appreciated.

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Originally Posted by elvis

Hi, was hoping someone could help with an outdoor pool heat pump that is not reaching or maintaining temperature.
For the last 3 weeks the pool has had no cover. At first I thought this was the problem as ambient temperature is between 16-22C day and 8-12 night. But the customer says that pool has never maintained temp even when covered in warmer months.
They have had two of these 60kw heat pumps on two matching pools. The first one lasted only one month before compressor failure. It was replaced with a 50kw unit that seems to be easily reaching temp (with a cover).
Pool is 16m x 8m and holds 160,000lts. Set temp is 27C but is only reaching 21C to 25C depending on ambient temp, sunlight hours and wind.
Do I just have too much heat loss due to evaporation, or another faulty unit? The owner is convinced that the heat pump is at fault and pool is due to close in one week (before cover is repaired).
Heat pump uses 410A refrigerant,
Air on 16.5C
Air off 10.4C
Discharge press 295psi, temp 51C
Suction press 95psi, temp 10.5C
Liquid line temp 26C
Water in 24.5C
Water out 28C
Any help or ideas appreciated.

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Your water flow through the condensor is to low.
Check this first, water split and discharge should reduce, if corrected

Could the condenser perhaps be under-sized?

What would typical pumping rates be for this kind of pool?

My calcs show that currently, if the system were indeed delivering 60kW, that the balancing water mass flowrate would be around 246kg/min.

What diameter water pipes connect to the system?

Thanks. I will try adjusting water flow today and see if that makes a difference.
The water connections are 50mm. The Heat pump is a Temperzone outdoor unit retrofitted with 3 x shell and tube heat exchangers in series.

Quote:

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Originally Posted by elvis

Thanks. I will try adjusting water flow today and see if that makes a difference.
The water connections are 50mm. The Heat pump is a Temperzone outdoor unit retrofitted with 3 x shell and tube heat exchangers in series.

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So it is not a HOT WATER HEAT PUMP LIMITED model, just one that has been Knocked up.

Sorry, yes it is HOT WATER HEAT PUMPS unit. Model 7GP60-3T.
The name plate on electrical panel says it's a Temperzone OSA405RKTV.
You were right about the low water flow. Pool cleaner has noted that water level keeps dropping below skim drains reducing water flow.
Will check later today for an improvement.