HVAC Help anyone?

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whubbard

HVAC Help anyone?
« on: 26 Apr 2009, 03:58 am »
Hello my fellow DIY/Handymen.

My small Haier AC unit seems to be acting up.
It appears the cooling unit is covered in frost, which is resulting in it not actually cooling. I tried to scrape a bit away, only to discover ice.

Here is a photo:


Does anybody know what the issue is?
Is it easily fixable?

Thanks Guys!

-West

markC

Re: HVAC Help anyone?
« Reply #1 on: 26 Apr 2009, 05:15 am »
The Lab is probably not the place for this.
If the filter is not plugged then it likely has a refrigerant leak. If it has a leak, it's junk.

JakeJ

Re: HVAC Help anyone?
« Reply #2 on: 26 Apr 2009, 07:31 am »
I think the Lab is a fine place to ask a question like this.

West,

I work in a food processing plant and see this type of problem regularly.  About 90% of the time it is, in fact, a refrigerant leak.  A qualified repairman can fix it but the question is whether it's cost effective to do so.  Since it is a window unit you can at least take it to the shop yourself saving a house call charge.  Call around a see if you can get a diagnostic check for a reasonable rate.  Once it is diagnosed you can make the call as to fix or replace.

That said, first let it thaw out and all the ice melt completely then check the filter(s).  Try and run it and if ices back up then you will need to see if it's repairable.  Oh, never chip or scrape ice off the coils as this the easiest way to kill an air conditioner.  Always just let it thaw on it's own.  Placing a fan blowing room temp air on it will speed things up a bit.

Good luck and hope this helps,
JakeJ

whubbard

Re: HVAC Help anyone?
« Reply #3 on: 26 Apr 2009, 02:57 pm »
Thanks Jake,
It has a fan only mode, which made it thaw pretty quickly.

Only problem now is that I feel like it's not getting as cold as it used to, so I feel like that would point a refrigerant leak, yet at the same time it's not frosting anymore.
The unit only cost $100, so I doubt it really economical to fix. I think I'll just leave it as is and if it really stops cooling, I'll crack it open and see what I can do myself.

-West

p.s. Water is meant to come out of AC units, correct? Right from the beginning there has been water (maybe refrigerant) coming out of the unit...

markC

Re: HVAC Help anyone?
« Reply #4 on: 26 Apr 2009, 03:47 pm »
Condensate should come out of the unit when running. The more humidity in the air, the more condensate. If refrigerant was leaking, it would leak as a gas not a liquid. Oil could come out of the leak zone. If you play with it yourself be very carefull. The refrierant is under pressure. If you cause a major leak by messin' around, it will come out in a hurry. If it contacts your skin, frostbite will occur. If it contacts your eyes....
Your statement of it not feeling as cold as it used to also points to a leak.

JakeJ

Re: HVAC Help anyone?
« Reply #5 on: 26 Apr 2009, 04:17 pm »
I concur with MarkC, it has lost enough refrigerant that it is no longer working correctly. Just get a new one before it gets hot in your area and all the air conditioners have been bought up.

It's best for the environment to take it to an appliance recycler so they can properly evacuate the remaining refrigerant before sending it to the landfill.  There is usually a small fee for this.

Keep cool,
JakeJ

JerryM

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Re: HVAC Help anyone?
« Reply #6 on: 26 Apr 2009, 04:39 pm »
HVAC icing is caused by three things: Dirty coils, dirty filters, and low refrigerant levels. Any of these things, or any combination thereof, will cause a unit to ice.

A minor refrigerant leak is not a reason to just can a unit. As stated in a post above, there is oil inside the unit. The oil is there to act as a gasket around the compressor shaft. The oil will not allow the refrigerant molecules to escape. However, if a unit has sat idle for a long period, say all winter, refrigerant can escape.

Clean the coils. Clean or replace the filters. Call some local HVAC folks and see what they would charge you for a recharge if you brought the unit to them. Expect to pay one hour of Tech time and the cost of any refrigerant you use. It will work better than new after that.

Recharging refrigerant is normal, from cars to major-tonnage roof top chillers. Items like household refrigerators are not susceptible to this problem as they are not "off" long enough for the compressor shaft to completely dry.

Clean or replace the filters every month and clean the coils every spring. It'll work just fine.

Have fun,
Jerry

JakeJ

Re: HVAC Help anyone?
« Reply #7 on: 26 Apr 2009, 05:01 pm »
JerryM's advice is also excellent.  A couple of phone calls will likely be the determining factor as to fix or can and replace the unit.  As MarkC stated an oil stain on the coils or tubing will be a sure sign of a leak and coils can be soldered or braised to cure a leak.

You have enough information now to figure out what to do.  Good luck.

Best Regards,
Jake

markC

Re: HVAC Help anyone?
« Reply #8 on: 26 Apr 2009, 06:35 pm »
Jerry, what shaft do refer to? It's a $100 window shaker. It obviously has a hermetically sealed compressor.

JerryM

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Re: HVAC Help anyone?
« Reply #9 on: 26 Apr 2009, 07:18 pm »
Jerry, what shaft do refer to? It's a $100 window shaker. It obviously has a hermetically sealed compressor.

Right. Same with my car. It's hermetically sealed with an oil bath. No bath, no seal. It just needs to be recharged (and maybe a filter and coil cleansing).  :thumb:

Have fun,
Jerry

markC

Re: HVAC Help anyone?
« Reply #10 on: 26 Apr 2009, 08:17 pm »
Ah, but your car is semi-hermetic with an external drive. The window shaker is driven by the electric motor that is inside the hermetically sealed can. :wink:

whubbard

Re: HVAC Help anyone?
« Reply #11 on: 26 Apr 2009, 09:38 pm »
However, if a unit has sat idle for a long period, say all winter, refrigerant can escape.

Yep!

I let it defrost, then cleaned the filter. It's no longer frosting, but does appear to be a bit warmer than usual.
So I'm assuming it just needs more refrigerant. Is it possible to order some and do it myself? Or is that a bad idea...

Thanks Guys.

-West

mightym

Re: HVAC Help anyone?
« Reply #12 on: 27 Apr 2009, 12:55 am »
Unless you have a license, I doubt if you'll be able to purchase the refrigerant.  The charging process, if done correctly, will have to isolate the leak, repair it, and then evacuate the unit and re-charge it by weight.

This requires some special tooling used only for the purpose, it is not something you should even consider.  Window units have one advantage over split systems, they are factory built, and charged.  They are much less prone to leakage because of the construction.  Under normal circumstances, with proper maintenance, the compressor should wear out before you need to do anything to the refrigerant circuit.

Any appliance repair shop who proposes to repair a refrigerant leak any other way is a clip joint, and will be ripping you off.  It may well work for a while, but you will be paying him to fix it again if not done right the first time.  If you do disassemble it, look for any oil collecting dust on the unit, that's a good place to start looking for the leak. 

I've been out of the HVAC biz for almost 20 yrs.,  but the systems haven't changed to the extent that the above advice would steer you wrong.  If you only paid a C note for it in the first place, I suspect that a reputable shop would advise replacement over repair, and can recycle it for you.  don't let them charge you too much for the recycling.  there's quite a bit of alum/copper in the unit that they'll sell. 

My first home had a 24K Btu window rattler that would cool the whole house,it was 20 yrs old when I moved in, and still running 13 yrs later when I moved out, all I ever did was replace the fan motor, and clean the coils/fan impellers.


John

markC

Re: HVAC Help anyone?
« Reply #13 on: 27 Apr 2009, 02:20 am »
I've been out of the HVAC biz for almost 20 yrs.,  but the systems haven't changed to the extent that the above advice would steer you wrong.


Lucky you!
I've been in it for just over. You give sage advice.