Mystery motor in portable AC unit
#1
08-11-16, 03:20 AM
Mystery motor in portable AC unit
Hi, I'm working on a 12000BTU portable aircon unit, model number MPN1-12CRN1-QB6.
I can work out what almost all the components do, except for a small motor at the bottom of the unit, much smaller than the fan motors, in front of the condenser. When the compressor is running, the mystery motor drives a shaft that enters the condenser at its bottom corner. It doesn't appear to be geared, so the shaft runs quite fast.
The condenser is about 3" thick, and must have some driven mechanical components inside it, but I can't see into it to figure out what they might be. Condensate water appears to trickle down from the evaporator to the condenser, so my best guess is that it's some kind of stirring device to help more water evaporate into the exhaust air, to assist with cooling the condenser. However the motor still runs in dehumidifier mode, which strikes me as odd.
Can anyone explain what I'm seeing? I can post some pictures if they would help. Thanks.
I can work out what almost all the components do, except for a small motor at the bottom of the unit, much smaller than the fan motors, in front of the condenser. When the compressor is running, the mystery motor drives a shaft that enters the condenser at its bottom corner. It doesn't appear to be geared, so the shaft runs quite fast.
The condenser is about 3" thick, and must have some driven mechanical components inside it, but I can't see into it to figure out what they might be. Condensate water appears to trickle down from the evaporator to the condenser, so my best guess is that it's some kind of stirring device to help more water evaporate into the exhaust air, to assist with cooling the condenser. However the motor still runs in dehumidifier mode, which strikes me as odd.
Can anyone explain what I'm seeing? I can post some pictures if they would help. Thanks.
#2
08-11-16, 05:24 AM
Group Moderator
#3
08-11-16, 05:52 AM
Member
it is most likely the "slinger" motor, that splashes or sprays water onto the condenser. The object is to get liquid water onto the condenser, not vapor in the air. The hot condenser evaporates the water. The heat required to evaporate the water cools the condenser over and above what the air stream can.
It is a little odd that it runs in dehumidify mode, but evidently the additional efficiency obtained offsets the added moisture, that then has to be removed...
It is a little odd that it runs in dehumidify mode, but evidently the additional efficiency obtained offsets the added moisture, that then has to be removed...
#4
08-11-16, 10:27 AM
Group Moderator
Welcome to the forums. You should enter non-US into your bio for us.
Appliances in the UK are sometimes built different then the ones we have here in the States.
Your unit is manufactured by Midea of Malaysia. Good luck finding any useful technical information on it. I couldn't even find a users manual in English.
I do see that unit has a powered front cover and louver. That would also require a motor.
Appliances in the UK are sometimes built different then the ones we have here in the States.
Your unit is manufactured by Midea of Malaysia. Good luck finding any useful technical information on it. I couldn't even find a users manual in English.
I do see that unit has a powered front cover and louver. That would also require a motor.
#5
08-12-16, 04:38 AM
CarbideTipped, thanks for the answer, that's pretty much what I suspected, thank you for confirming.
PJmax, done. I hadn't spotted the non-US option as it was hidden under 'state'. Thank you for taking the time to look for the manual. It does appear to be manufactured by Midea, although it is branded as 'Pump house', a UK reseller.
I have some more questions - the unit has two condensate drain connections, one at the bottom of the unit, which drains the collection tank, and one in the middle of the unit, which drains directly from under the evaporator.
Am I right in thinking that if I drain the condensate from the upper connection the 'slinger' motor will serve no purpose and can be disconnected, as the condenser will remain dry?
One other question - I see there's a temperature sensor on the evaporator coil; is the only purpose of this to turn off the compressor as the evaporator temperature approaches freezing, to prevent it icing up?
The reason I'm asking these questions is that I want to adapt the unit to a permanent installation. Connecting it to a control system of my own design means I will have to bypass the units own controls.
Thanks.
PJmax, done. I hadn't spotted the non-US option as it was hidden under 'state'. Thank you for taking the time to look for the manual. It does appear to be manufactured by Midea, although it is branded as 'Pump house', a UK reseller.
I have some more questions - the unit has two condensate drain connections, one at the bottom of the unit, which drains the collection tank, and one in the middle of the unit, which drains directly from under the evaporator.
Am I right in thinking that if I drain the condensate from the upper connection the 'slinger' motor will serve no purpose and can be disconnected, as the condenser will remain dry?
One other question - I see there's a temperature sensor on the evaporator coil; is the only purpose of this to turn off the compressor as the evaporator temperature approaches freezing, to prevent it icing up?
The reason I'm asking these questions is that I want to adapt the unit to a permanent installation. Connecting it to a control system of my own design means I will have to bypass the units own controls.
Thanks.
#6
08-12-16, 08:41 AM
Group Moderator
You're basically on your own. You're not going to find a helpful service manual for your unit.
The owners manual should address the drain fittings.
The temperature sensor in front of the evap must remain. The unit needs to know when the coil is freezing up. It may also be used to determine room air temperature. Some units have two sensors.
The owners manual should address the drain fittings.
The temperature sensor in front of the evap must remain. The unit needs to know when the coil is freezing up. It may also be used to determine room air temperature. Some units have two sensors.
#7
08-15-16, 02:22 AM
Yes I understand that. I will keep the temperature sensors in my system. I just wanted to make sure the evaporator sensor's only purpose is to prevent freezing. Thanks for your help.
