break room a/c

[valdelocc]

Last week I got a call for a breakroom that was too hot,got there and found a 22000btu window unit not working due to a locked out comp. I' wacked it with a rubber mallet and it kind of ran for a few minutes and locked again,one of the guys that works in that area told me that they had at least 4 unit gone bad over a 3 years period, due to the nasty enviroment (dust,oil) generated by the machines around the breakroom.
My boss got a cuote for a new a/c for around $750.00 ,I told him that something most change or the new one will follow the same luck,My idea is to take the old unit remove the locked samsung comp,install a matsu****a 220/1/228000btus comp.a high-low pressure cutout (manual reset) an 24v trans,a set of contactors and a preset (68-70) bulb type t-stat pretty much like a residential split system. Any feed back would be greatly appreciated.

[Wild Leg]

Originally posted by valdelocc
Last week I got a call for a breakroom that was too hot,got there and found a 22000btu window unit not working due to a locked out comp. I' wacked it with a rubber mallet and it kind of ran for a few minutes and locked again,one of the guys that works in that area told me that they had at least 4 unit gone bad over a 3 years period, due to the nasty enviroment (dust,oil) generated by the machines around the breakroom.
My boss got a cuote for a new a/c for around $750.00 ,I told him that something most change or the new one will follow the same luck,My idea is to take the old unit remove the locked samsung comp,install a matsu****a 220/1/228000btus comp.a high-low pressure cutout (manual reset) an 24v trans,a set of contactors and a preset (68-70) bulb type t-stat pretty much like a residential split system. Any feed back would be greatly appreciated.

Spend the money toward new equipment.

Even the best field compressor replacement is not as desirable as a factory installation. Multiple failures can usually be tracked to poor practices by the parts changer.
Four units in three years is probably not just a dirty environment. Every time a compressor fails, it contaminates the system.
By the time you buy a compressor, refrigerant, at least one suction drier, a liquid line drier, capillary tubes, access fittings, couplings, ells, brazing alloy & gas, nitrogen purge gas, and other miscellaneous items, you are pretty close to the price of a new window unit.
The new one has all new parts, with a warranty.

One thing that needs to change is the care of the window unit.
Keep the coils clean on the new one.

Make sure the new window unit is not oversized.
Short-cycling kills compressors.

Better than a window unit, look into a mini-split.
The outdoor unit can be placed where it can breathe.

[valdelocc]

bwal2,I' would like to know why field replacement are not as desirable as factory installation?
From my point of view a coil is just that same applies to a metering devise , add the right compressor to the loop and you are good to go,after that its up to the tech to follow up the universal cooling-refrigeration rules.
In this particular case for the past few years the people incharge have desided to overlook the reasons why the a/c failed and spend more and more money in new units,they dont care is not their money.I' havent seen a single window unit that has any safety devices built into it from the factory,and I' think that by incorporating some of them to it I' could extend its life greatly. As far as installing a mini-split system,I' look into it and the owners won go for it.
I' would also like to know how can you get 2 tons of cooling out of a window unit that has such an small coils?
it bugs my mind!
Thanks for your replay!

[Wild Leg]

Originally posted by valdelocc
bwal2,I' would like to know why field replacement are not as desirable as factory installation?
From my point of view a coil is just that same applies to a metering devise , add the right compressor to the loop and you are good to go,after that its up to the tech to follow up the universal cooling-refrigeration rules.
In this particular case for the past few years the people incharge have desided to overlook the reasons why the a/c failed and spend more and more money in new units,they dont care is not their money.I' havent seen a single window unit that has any safety devices built into it from the factory,and I' think that by incorporating some of them to it I' could extend its life greatly. As far as installing a mini-split system,I' look into it and the owners won go for it.
I' would also like to know how can you get 2 tons of cooling out of a window unit that has such an small coils?
it bugs my mind!
Thanks for your replay!

Why is a heart transplant generally not as successful as the one you were born with?

The old compressor failed for a reason. Until that reason is identified & corrected, repeat failure is guaranteed.

This little window a/c has already had multiple failures, if I read your original post correctly.

The reason field replacement is not as successful is because of contaminants (oil, oxides, etc.)in the system, left by the death of the previous compressor(s).
No matter what your skill level, a new, fresh-from-the-factory complete system wins every time.

750 bucks for 2 tons.
There's your answer.
Window units are typically low end items, with minimal protective devices.
They work quite well, with normal usage.
Yours is not normal usage.

Adding additional controls could increase the longivity of a unit, but I wouldn't start with one that has a history of failure.
Remember, you will void the UL listing of the window unit if you modify the wiring & controls. You'd better be REAL good at it, and have REAL good insurance, because the manufacturer is no longer liable. You are 100% liable if something goes wrong.
Be sure you really are in love, since you will be married to this unit. Anybody else will condemn it immediately as soon as they see it was built by Frankenstein. They will also trash your skill level.

The manufacturers use smoke and mirrors to make the little coils produce big results.

There may already be a commercial ptac that already has the bells & whistles you are dreaming of. Maybe somebody on this forum has seen one.

Ask around.

(By the way, if you decide to go ahead anyway, make sure the new compressor actually will mount on the existing studs. Also figure the cost of a new capacitor, unless you are positive about the condition & rating of the old one.)

[maintenanceguy]

I have - only a couple of times - added a high and low pressure cut out to a PTAC.

But I'd agree that this one has lived a full life and limping it along any more seems like a lot of work to save $100.

[an "expert"]

No expert here, but why would a window unit run for years with no service, in a window?
My first guess would be mis-application of the unit and that would be reason for failures.
Always spend money wisely, yours or the customers.
On this job, it's not your money that you're spending, but you are supposed to be working in the customers best interest. Too bad if the solution costs more than the customer wants to spend.
I always recommend the solution that will do the best job and work properly. If I don't get the job due to high cost, too bad, on to the next one.
I've never had time off, that I didn't want, in 25 years.
Why put your reputation on the line for some system that will give problems and call backs? Who wins on a cheap job?
When I'm called in on a job it's my rep. and ticket on the line and I will never, I mean never, ( never can be a very short time.... LOL) put that at risk.

Sorry if I started to Rant and got off topic, but I've read one pile of dissappointing replies to threads today.

[Edited by an "expert" on 01-01-2005 at 02:47 PM]

[valdelocc]

bwal2,I'm planning to go ahead and install the new matsu****a I'm going to flush the hell out of the system ,install a LL filter,H,Lpco etc,I' think that matsu****a makes a far better comp. that samsung ,for that matter samsungs are botton of the barrell,I've done my fare share of transplants,I' just needed some advise as far as what to add to make the ptac last.I'm also the only one that will ever touch the unit maintenance wise.thank for your input!

[thehumid1]

I love the whackinf it will the mallet to unstick the compressor...personally let the employees sweat if it is just a break room this way they willl hang out there less and maybe actually do some work. But best bet is put in a new unit.