View Full Version : Mitsu High Wall

06-05-2002, 12:47 AM
Brian, this ones for you

Came across a high wall unit today, fitted by a plumber no doubt. Was a Mitsubishi, my question is:

Where does the refrigerant start expanding? At the condensing unit end or at the evaprator?

I know, in my experience they expand at the condensing unit end, hence, both lines insulated. This one wasnt. Had a 1/4" pipe, uninsulated, and I think a 5/8" or 1/2" insulated. I presumed the low pressure would start at the condensing unit end, pressure was a high 70 psig. The pressure on the return pipe, 5/8" sizxe was in deep vacuum.

It completely befuddled me

Rick Harris
06-05-2002, 10:28 AM
Hey Aiyub:Thought I would jump in;What is the model number of the Mitsi,and is it cooling only?They do start expansion from the outdoor unit so both lines should be insulated.My first reaction is a low gas situation but you ideally would weigh out the charge and reweigh in the correct calculated charge.Really this is the best way Have fun

06-05-2002, 09:52 PM
Thanks Rick,

Believe me, its no fun

I got this call out to this pizzeria, said cold room down. I get there, guess what, no cold room, well they think it is, its only a normal room, some wise guy has put rigid white plastic on the walls, left a normal standard wooden door in, and put in this dirty high wall unit in, and calls it a cold room. The roof is a false ceiling too!!

I dont know the model number of the Mitsubishi, I didnt check, all I said to the customer that I could turn the room into a proper chiller room and this is the cost.

Can you believe that they keep meet, dough, everything in this room. How does it pass the Health Department check???

Or does the Health Inspector not know that this room is not a cold room, maybe he gets a free pizza and overlooks it.

I saw chicken, pizza doughs, the whole lot in there. So next time you eat a pizza and start running to the toilet, BLAME ME

Cos, I never repaired that AIR CONDITIONER!!!!

He Heeeee

ps: Those pressures are still bugging me, I never found a leak, I saw an oil trace on the schrader point exiting the condensing unit, as for weighing the charge, strewth blimey, I wouldnt have the foggiest how much gas this unit takes or even about taking along my bathroom scales to weigh the charge

Incidentally, some years ago I was working on a site ( Installing Mitshubishi Air Conditioners no doubt) and I got freindly with the building contractor, he kept asking me about refrigeration, I also put in a cold store and a cellar cooling system, so I was there for a while.

I told him the basics, answered all his questions, even lent him my " Modern Refrigeration and Air Conditioning Book" ( and that was the last I saw of the book. Anyway, all credit to him, he learnt fast, soon HE TOOK OVER MY CONTRACT, on the next associated build, this time a big night club, ( same company) He kept ringing me asking for advice and I kept giving it to him, but then Ive got a good nature.

So I lost a lot of money ................ I only got that contract back last year, and Ive been sorting out all his errors, and there were many, anyway, to cut it short, I bump into my builder freind last week, we sat down and had a good chat, and then he tells me, "Guess what, Ive just finished installing 52 Mitshubishi Air Conditioners, ( I wont name where)

I didnt know whether to laugh or cry, vicariously I was proud that in some small way, probably I set him off on his route to prosperity, on the other hand everyone makes their own luck

I didnt have the heart to ask him for my book back, Me, I would be happy to get just one Air Conditioning job, let alone 52!!!

By the way, hes still a builder, who installs Air Conditioning , or anything refrigeration, given the oppotunity!!!

07-05-2002, 12:03 AM

That's a great story. You know.... the good guys really do end up on top!! :) I maintain relationships with my competitors in muach the same manner as you have described your interaction with your builder friend. If I'm not the factory Rep. for a product line, and a customer just wants to buy a part.... I'll send him to the (competitor) factory rep.

I find that what comes around, goes around.... and usually the favor is returned.

Of course, it seems in this case that you gave your friend enough information "to be dangerous"!! :D

That may really be a bankroll for you!

Rick Harris
07-05-2002, 05:59 PM
Aiyub;From the sounds of that job you would not have wanted it anyway!! Usually the Mitsi is shipped with enough of a charge for the specified amount of run that is shown on the nameplate,lets say 15 meters.Anything else is weighed in by scales.All the data is on the inside of the cover.I also had a laugh about your builder friend installing A/C.In Canada there is no more flared or mechanical fittings allowed so in order to install you have to be able to weld and now you have to be certified(note;not qualified)We had a lot of problems with tin wackers putiing kit in.Anyway Good luck