Heat pump hot air temp.

[Bitbin]

Hi. This may be a little off topic but thought you guys probably can help me answer this question i have. I got 2 split heat pumps in 2 rooms. One is 18k LG and the other is 12k some chinese cheap brand. The weather here is around 20°c so its not cold but when i tested them both on heating mode max temperature the lg blew much hotter air and they are both new with full refrigerant.

So my question is does a 18k heatpump actually blow hotter air or is it because the lg is just better built(fyi it blows colder aswell in cooling mode). The 18k has a heating kw rating of 5.4kw while the 12k has a rating of around 4kw. I saw on LGs website that their 12k model of the same heat oump also has a kw rating of a little over 4kw so does it mean doesnt blow as hot of air as its 18k sibling or should it be the same just a lesser capacity of heating a larger room? From what i have understood the btu rating is for how large of a room it can cool/heat but what is the kw rating for then? (And i dont mean power consumtion kw rating)

Thanks in advance.

 

[Supervstech]

Heating discharge air temp will be affected by room temp, airflow across the coil, refrigerant charge, and compressor mode.

Some models are designed to output only the heat needed to maintain a certain temp rise.
Increasing the blower speed, will lower the output air temp.

 

[Bitbin]

Well i did use the 12k last winter and it did struggle to heat the room past 23 degrees( its a 15 sqm room) while it was between freezing and 10°c outside and it didnt blow very hot air and still doesnt. It must be the model then as i measured the refrigant and had it installed by a proffesional.

So the kw rating doesnt tell how hot/cold the air come out?

 

[Warpspeed]

Increasing the blower speed, will lower the output air temp.

Yes indeed.
If you were to double the airflow, the temperature rise will be half for the same heating power output.

Output discharge temperature has very little to do with the amount of actual heating.

 

[prince_a]

Just to clarify something - heat pump like AC build on the concept of heat transfer, your not cooling or heat , you transfer heat from one place to the other.
their for the efficiency of the unit depends on factors of its state of temp inside and outside of the house and the unit design to deal with the heat transfer,
the BTU = Watt so each country using diff method to calculate - US- BTU - UK - WATT
1 Ton BTU ( 12000 btu ) = 3500W

 

[Bitbin]

Just to clarify something - heat pump like AC build on the concept of heat transfer, your not cooling or heat , you transfer heat from one place to the other.
their for the efficiency of the unit depends on factors of its state of temp inside and outside of the house and the unit design to deal with the heat transfer,
the BTU = Watt so each country using diff method to calculate - US- BTU - UK - WATT
1 Ton BTU ( 12000 btu ) = 3500W

Ooh ok so kw and btu are just difffrent names for the same thing. Thanks. I think this chinese model i got is just shitty compared to the LG one.

 

[Supervstech]

Well i did use the 12k last winter and it did struggle to heat the room past 23 degrees( its a 15 sqm room) while it was between freezing and 10°c outside and it didnt blow very hot air and still doesnt. It must be the model then as i measured the refrigant and had it installed by a proffesional.

So the kw rating doesnt tell how hot/cold the air come out?

Pros don't always know what they are doing.

You might want to get another pro to remove all refrigerant, weigh it to confirm volume, and install the correct amount.

 

[webbbn]

Pros don't always know what they are doing.

A few years back I spent several K$ on a heat pump that was fully under warranty (I don't remember if it was initial warranty or extended by the contractor, but it was just a few years old) before they figured out that I had a leak somewhere in my coolant line. Two evaporator coils replaced, full recharge afterward, which I think was $1000 each just for for the coolant!

It worked fine for a winter, but then summer came along and my heat pump continued to pump out heat, no matter what setting it was on. The service man said it was the control board was bad and it was going to cost me (way too much) to replace it, so I sent him on his way and started researching AC repair. Turns out it was just a broken wire. I swapped it for an unused wire and fixed the problem in a couple of minutes.

I've done plenty of repair work myself, both as a professional computer technician and on the infinite number things that breakdown in a lifetime. I know that it can be hard to diagnose problems sometimes/often, but that time I think this stooped to the level of incompetence.

That also taught me that "warrantees" can be less than meaningless sometimes, which is why I mostly ignore them.