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Mini split wont cool when outside temp drops
- Thread starter Bewarned
- Start date
Some units have ambient switches which help to an extent, but once it gets super cold out, the a/c coils will freeze up unable to transfer heat
also, make sure your coils are clean and have enough freon in the system
also, make sure your coils are clean and have enough freon in the system
how cold are we talking about? the outside conditions i mean.
low ambient kits are for very cold freezing temps. i doubt you need one yet... but i live in houston, and have no clue what temps you might expect up there. cant be cooler than 60's though right?
smart ac systems are able to vary the head pressure according to ambient temperatures... IDK if any minisplits do this as ive no experiance with them, but the more sophisticated air sourced commercial systems do.
what this means is that the condenser... instead of regulating air flow to maintain a fixed temperature of the high pressure liquid refrigerant, regardless of air temps; instead of this, the systems drop the high side refrigerant temps as the temps outside drop... thus dropping head pressure and increasing capacity and efficiency.
this is the first thing i thought of when you mentioned poor performance.
assuming your system has this capability... perhaps you have a fault some where.
perhaps a faulty refrigerant temp sensor is keeping the fan from subcooling properly.
why this wouldbe the case for low temps and not high? i have 0 clue. its probably wrong to be honest.
whats more likely is its a coincidence... and your unit is failing or fouling, having nothing to do with the outdoor temps.
id suggest the following.
take temp readings of the high and low side refrigerant. compare to install plate specifications or the specifications inside the install manual.
clean the outdoor coil according to manufacturers recommendations.
clean the indoor coil same thing...
do all the other shit a home owner does to maintain his hvac system... kill high weeds and crap around the unit, inspect the shut off for scorching or heat from bad connections... excessive vibrations etc.
then come back here and report back.
low ambient kits are for very cold freezing temps. i doubt you need one yet... but i live in houston, and have no clue what temps you might expect up there. cant be cooler than 60's though right?
smart ac systems are able to vary the head pressure according to ambient temperatures... IDK if any minisplits do this as ive no experiance with them, but the more sophisticated air sourced commercial systems do.
what this means is that the condenser... instead of regulating air flow to maintain a fixed temperature of the high pressure liquid refrigerant, regardless of air temps; instead of this, the systems drop the high side refrigerant temps as the temps outside drop... thus dropping head pressure and increasing capacity and efficiency.
this is the first thing i thought of when you mentioned poor performance.
assuming your system has this capability... perhaps you have a fault some where.
perhaps a faulty refrigerant temp sensor is keeping the fan from subcooling properly.
why this wouldbe the case for low temps and not high? i have 0 clue. its probably wrong to be honest.
whats more likely is its a coincidence... and your unit is failing or fouling, having nothing to do with the outdoor temps.
id suggest the following.
take temp readings of the high and low side refrigerant. compare to install plate specifications or the specifications inside the install manual.
clean the outdoor coil according to manufacturers recommendations.
clean the indoor coil same thing...
do all the other shit a home owner does to maintain his hvac system... kill high weeds and crap around the unit, inspect the shut off for scorching or heat from bad connections... excessive vibrations etc.
then come back here and report back.
could also be something incredibly mundane also btw...alot of these fancy minisplit VRF systems have untold numbers of system configurations meant to optimize energy consumption or what ever else.
its entirely possible that some jumper some where, or thermostat or what ever, is programmed inappropriately. you might look into that too.
is the condenser fan running full blast outside?
give us some idea of how this thing was installed too... hacky DIY job or pro install?
its entirely possible that some jumper some where, or thermostat or what ever, is programmed inappropriately. you might look into that too.
is the condenser fan running full blast outside?
give us some idea of how this thing was installed too... hacky DIY job or pro install?
yeah, you prob need the low tmep kit like AL said
when the AC stops cooling when outside temps drop any lower than what your lowest AC temp setting is.
the higher end mini splits are usually already equipped with them.
my mitsu and friedrich both have them.
your owners manual it should shed lite on what or have or not
I hope this is not bad manners to ask you this here, if so let me know.
Gavita Holland told me that for 20x1000w hps and 20x LEP would take 88k btu ac to cool just the light load in room. I was looking at putting 2x 60000 btu mini splits in they have 5 heads each 12k btu per head. It is the newer energy star 21 SEER DC inverter and has the low ambient temp operation to 5 degrees F. Have you had any experience with these type of ac units? I liked the fact that it would run at a lower power vs typical ac units that kick on at full power till room was cool then kick on again at full power etc. The inverter tech claims that this will run all the time at a lower rate but keeps the room dead on. I was worried that a unit would fail to cool in the Winter hence the OPs concerns with this thread. However this unit claims to operate down to 5 degrees. Is this the route that you would take? They are just over $4k each, I'd hate to put all this in and have it not do the job. Thanks for your time.
