ᐅ Is the supply temperature of the air-to-water heat pump too low?

Hello everyone, we have an air-to-water heat pump from Elco; Aerotop Split 07. We live in a single-family house of 150 square meters (1,615 square feet), without a basement, and there are two of us. We have a mechanical ventilation system with heat recovery and a photovoltaic system on the roof. The whole house has underfloor heating. I have now made some adjustments to the heat pump during the second winter. I noticed that the hot gas temperature is always very low. I have already talked to the Elco technician about this, who assured me twice by phone that everything is fine. However, when I search online about the temperature, it doesn’t seem to be the case. I recorded the data over a few weeks. Here are some excerpts showing the hot gas temperature in different operating modes.

Domestic hot water:
Hot gas temperature: 90 to 105 degrees Celsius (194 to 221 degrees Fahrenheit)
Compressor speed: 85 Hertz
Flow temperature: 50 to 60 degrees Celsius (122 to 140 degrees Fahrenheit)
Return temperature: 45 to 55 degrees Celsius (113 to 131 degrees Fahrenheit)
Evaporator temperature: -4 degrees Celsius (25 degrees Fahrenheit)
Suction gas temperature: -4 degrees Celsius (25 degrees Fahrenheit)
Flow rate: 23 liters/min (6 US gallons/min)

Heating:
Hot gas temperature: 17 to 34 degrees Celsius (63 to 93 degrees Fahrenheit)
Compressor speed: 21 Hertz
Flow temperature: 26 degrees Celsius (79 degrees Fahrenheit)
Return temperature: 24 degrees Celsius (75 degrees Fahrenheit)
Evaporator temperature: 6 degrees Celsius (43 degrees Fahrenheit)
Suction gas temperature: 10 degrees Celsius (50 degrees Fahrenheit)
Flow rate: 15 liters/min (4 US gallons/min)

The house is getting warm. If this is a fault, how can I prove it so that Elco does not charge fees for the service visit?

Everything looks fine at first glance. Where exactly is the problem?

I also don’t understand the problem. These are values that you often don’t even see on many heat pumps (I don’t on mine either) or that are simply not relevant. The house gets warm, the supply and return temperatures look reasonable, and heating costs are probably within a manageable range.

I had read online and in various forums that the discharge gas temperature should be about 25 to 30 degrees higher than the flow temperature during normal heating operation. If this is not the case, damage to the compressor may occur. Therefore, I thought my discharge gas temperature was too low. I recorded both temperatures for 10 consecutive days. The discharge gas temperature was only a few degrees above the flow temperature. On two days, the discharge gas temperature was even below the flow temperature. I compared the two temperatures in a forum with someone who has the same heat pump as I do. During their heating operation, the discharge gas temperature was indeed about 30 degrees higher than the flow temperature. Of course, the existing conditions differ in their case.

Just because someone on the internet says it has to be that way, I wouldn’t get worked up about it. I tend to find statements suggesting that a high turbo outlet temperature negatively affects the service life. Are there any actual symptoms, or are you just bothered by the low number?

RotorMotor schrieb:

Just because someone on the internet says it has to be this way, I wouldn’t let it stress me out.
I actually find more statements suggesting that a high hot gas temperature is detrimental to the service life.
Are there any symptoms, or are you just bothered by the low number?

Okay, then I will file this away. I did actually get worked up because I understood that too low a temperature would negatively affect the compressor. However, I haven’t noticed any negative effects myself. I only came across this because I was researching optimizations for the heat pump online.