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Thread ID: 118931 2011-06-27 06:35:00 heat pump question globe (11482) PC World Chat
Post ID Timestamp Content User
1212550 2011-06-29 01:16:00 The Mitsubishi HeatPump I am using at the moment definitely dehumidifies the room it is in, at the moment the inside temp is 18degC 53% humidity, outside it is 6.4degC 89% humidity.

When I come into the room after a few hours away the inside and outside temperatures and humidity will be the same but within 15 minutes of the heat pump being on the humidity will drop to about 64% and the temperature increases to whatever I set, within reason.
They don't dehumidify during a heating cycle so there must be another reason for the drop you are experiencing.
mikebartnz (21)
1212551 2011-06-29 01:41:00 The one I am using blows cold air out the top and warm air out the bottom, the cold air path is the dehumidified air and the hot air from the bottom is the heated air.

It sucks air in through the middle front of itself, it is a floor standing unit, there are no other heating or cooling machines of any type which are powered in the room.

Outside there is a drain pipe which comes through the wall from the inside unit and releases the moisture from the dehumidifier.
zqwerty (97)
1212552 2011-06-29 02:33:00 Outside there is a drain pipe which comes through the wall from the inside unit and releases the moisture from the dehumidifier.
They all have that and some have a condensate pump because of their position.
What make of Mitsi is it as I will enquire from my mate who is in the game but from what you say it must have two separate parts as warm air has to go over a cool element to dehumidify.
mikebartnz (21)
1212553 2011-06-29 04:52:00 I just wear a down jacket in my room :D My own heater is kept off. Until I go to the lounge which has HP. Nomad (952)
1212554 2011-06-29 07:07:00 Mitsubishi Electric
K-Inverter
Room Air Conditioner
MFZ-KA35VA
zqwerty (97)
1212555 2011-06-29 07:08:00 I suspect that your humidity reading is changing as the room warms up is because your are measuring "relative humidity" not absolute humidity: as the room warms up, the air can hold more moisture. The relative humidity is a measure of the proportion of water vapour the air has, compared with how much it can actually hold at that particular temperature (before it becomes saturated). So if the absolute moisture level stays exactly the same as before, as the room warms up, the "humidity" reading you are getting will be lower than when the room is cold. ellpow (16400)
1212556 2011-06-29 07:24:00 Globe: I thought our heat pump was blowing cold air, so stood on a chair up to the wall console and held a thermometer in front of it for about 30 minutes a couple of week ago: thermometer went right up to 45 deg C if it is directly in the blower stream - took about that long to reach that temp. (I had the inverter heat pump set for 30 deg C, "strong", to take the measurement.) We also run a fan to bring the warm air at ceiling height back down to where we are. The room is too big for our 6kW heat pump (shifted from a smaller house), so it would never switch off, so we don't keep it on as it runs all day and would cost 60 cents an hour for 24 hours. ellpow (16400)
1212557 2011-06-29 08:44:00 Globe: I thought our heat pump was blowing cold air, so stood on a chair up to the wall console and held a thermometer in front of it for about 30 minutes a couple of week ago: thermometer went right up to 45 deg C if it is directly in the blower stream - took about that long to reach that temp. (I had the inverter heat pump set for 30 deg C, "strong", to take the measurement.) We also run a fan to bring the warm air at ceiling height back down to where we are. The room is too big for our 6kW heat pump (shifted from a smaller house), so it would never switch off, so we don't keep it on as it runs all day and would cost 60 cents an hour for 24 hours.

That's a bummer, must be a really huge room or you don't have it set correctly, eg the louvres on it are not set to point downward.

LL
lakewoodlady (103)
1212558 2011-06-29 08:56:00 Right now I have inside 18.4degC 53%, outside 4.8degC 81% measured using D.S.E. Deluxe Weather Station with outside remote unit, if I bring the remote unit inside it quickly corresponds to the main unit readings. zqwerty (97)
1212559 2011-06-29 08:58:00 Mitsubishi Electric
K-Inverter
Room Air Conditioner
MFZ-KA35VA
Well I had a word with my friend and he said as ellpow put it. The reason you are getting that reading is because as the room warms up the air can hold more moisture so you are effectively getting a false but true reading.
mikebartnz (21)
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