I have had installed 4 Mitsui AC units. The 2 x 12 units work fine
cooling the rooms quickly but the 18 and the 24 are having issues and
are currently being investigated.
The 24 unit outside is MVE XO 24 HL4 and has been married to an inside
unit MVE XI 18 HL4. Surely both should be 24 spec? The installers have
said the 18 and 24 inside unit are the same but I'm not really
I'm unable to see the 18 units external serial number as its located
too far away.
Thanks for any help
I have no problem but apparently you do!!!
#1 if your condenser is over size you have condition where Evaporator will
and needless to say sweating of registrars water drip?
#2 If you condenser is undersized compare Evaporator then you dew pint will be
that no Humidity will be remove and less cooling, either way it will be
So if is going to work yes but how???
Get real! Evaporators sweat - fact of life. You're trying to say
that the orifice of the evap valve somehow renders the whole evap
useless. Hardly. It is only a little more efficient - pressures
didn't change the whole length of the evap should be boiling fluid for
the highest efficiency. At worst case, you may have paid for more
evap tubing than the system can use.
Now I'd have to question your grasp of physics.
Look, I don't like it any more than you - but technology develops with
time. We are all becoming obsolete - I know I've seen it in
electronics - nowadays a degree is near useless for something like
analog electronics - programs can do that better than the young
engineers of today. That's life. Now a day so called engineers are
learning to run before they learn to stand - let alone run (in
electronics) They design whole systems with logic, and no or little
understanding of the physical laws they are using.
Newspapers? With real paper?
I'm sure the best buggy whip manufacturer had the same lamentation.
People, ultimately, will be useless (or for all practical purposes,
save the top geeks) That's the way we designed the world to work, and
it is doing what it was designed to do.
Adapt, retire or perish. Them's the choices.
Wrong, as long as you have the proper orifice or expansion valve for the
compressor capacity along with the proper airflow it is fine, the problem
with an undersized evap is that at the necessary airflow the velocity will
be so high it slings water off of the coils instead of it draining into the
It is fairly common practice to oversize the evap by 1/2 ton to reduce the
static pressure drop across it and increase surface area for better
dehumidification. It doesn't matter if the evap is the size of a Sherman
tank as long as it has the necessary 350-400 CFM per ton of air flowing
A 1/2 ton oversized minisplit indoor unit is a good thing, as long as it has
a TXV and a multispeed or variable speed fan, when it is hot inside you can
run it on high and increase the sensible heat removal at the expense of
latent to get the temp down then turn down the fan speed to get out the
The problem is that the evap coil is 25% undersized.... in heat mode, the
system is going to shut down on high pressure safetys. Inless its a high end
mini-split, its not going to have a TXV, or VFD to compensate.
What he has done is the equivelant of pitting a 3 ton evap on a 4 ton
condenser. That dog won't hunt,
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