GFCI and Window AC Fires

[rruiz642]

Hello folks,

I'm currently deployed in Southwest Asia. We have approx 4,000 window AC units that run contantly. Fequently, when high humidity (80+%) builds up at night (mainly), we have up to a dozen of these critters catch on fire.

It is believed that condensation drips on the motor/condensor and sparks the short/fire or a dirty filter/clogged drain hole that build water in the drain pan. We have a lot of blowing sand out here. Last year, nearly all breakers (4,000+) were exchanged with GFCI breakers to help prevent this problem (AFCI at that time did not fit our panels).

This season, we have continued to these fires, but I think there is a misconception of either how the fires start or the purpose/benefits of the GFCI breakers. Each window unit is on it's on circuit. Aside from the fires, we have nuisance tripping contantly in the high humidity/build up of water in the pans.

Since I not an expert on AFCI/GFCI protection, my question is: "is it a waste of $$ to purchase GFCI breaker or RCD/GFCI outlets in hopes of preventing a fire." While the breakers have a 30mA setting, will a short in the motor cause in imbalance that an GFCI/RCD will detect or will the just the short just create a high return amperage that will eventually be caught by the circuit breaker portion of the device (20A)?

Thanks for any advice/lessons

Richard
SouthWest Asia

 

[petersonra]

I would go with the misconception. I think it is unlikely that condensing water is causing motors to spark. It might cause them to fail, but to spark???

What inside an A/C would burn in the first place?

Are these things even rated for the ambient temperatures they are seeing?

 

[bphgravity]

It sounds like you have a maintenance problem. GFCI's are not designed to prevent a condition that could result in fire, but will serve that purpose if the faulting condition happens to be creating enough energy to ignite combustible materials at or around the fault. Nealry all the RCD's work on the same principle.

Where exactly does the fire originiate? Does the appliance iteself catch fire or the electrical components/wiring? Clothes dryers can and have also caught fire when vented incorrectly or not maintined free of lint build up. Perhaps the solution is NOT an electrical one.

 

[al hildenbrand]

I'll be the third to ask for more detail.

Have you seen the burned units and examined what actually burned?

Any clues that you have will aid this discussion.

Both GFI and AFCI have some inherent blind spots.

 

[LarryFine]

My guess: under-voltage is causing over-current and destructive temperatures, probably burning insulation..

 

[infinity]

Since I not an expert on AFCI/GFCI protection, my question is: "is it a waste of $$ to purchase GFCI breaker or RCD/GFCI outlets in hopes of preventing a fire." While the breakers have a 30mA setting, will a short in the motor cause in imbalance that an GFCI/RCD will detect or will the just the short just create a high return amperage that will eventually be caught by the circuit breaker portion of the device (20A)?

For the record, a device with a 30ma trip would be a GFPE device not a GFCI device.

 

[boboelectric]

All of the a/c window units in our facility (+300) in the last 30 years,we never had a fire.A failure,yes.A burnout,yes.No fires.
Bob O.84,Pa.

 

[ramsy]

Are people hanging flammable materials from the AC, perhaps using the relatively warmer and dryer AC exhaust fan to dry their clothes?

The first time I saw a room AC unit filled up with water from condensation, I drilled a 1/4" drain hole in the lowest part of the bottom pan. Water accumulated right underneith the fan, which then sprayed the water everywhere inside the unit.

I could not understand why a major AC Mfg., GE, would omit a simple drain hole in the bottom. This practice seems to be a damaging oversight.

After looking at the Mfg. warranty, and seeing a one year guarantee on major parts & labor, I realized thats about how long it would have taken corrosion or a short circuit to destroy the unit, as the internal fan sprayed water everywhere.

The 1/4" drain hole eventually corroded & clogged and was redrilled to 3/8", but this unit has run perfectly for over 3 years now.

 

[iwire]

The first time I saw a room AC unit filled up with water from condensation, I drilled a 1/4" drain hole in the lowest part of the bottom pan. Water accumulated right underneith the fan, which then sprayed the water everywhere inside the unit.

I could not understand why a major AC Mfg., GE, would omit a simple drain hole in the bottom. This practice seems to be a damaging oversight.

You might not want to add the drain hole.

It is not a 'damaging oversight' but a design choice made by more of the manufacturers of window units to increase the efficiency.

The fan is designed to sling condensate water over the condenser coils increasing the heat transfer.

 

[LarryFine]

The fan is designed to sling condensate water over the condenser coils increasing the heat transfer.

"Uh, your honor, I'd like to know whether the witness's testimony is opinion or fact!" ~ Mr. Trotter, D.A. ~ My Cousin Vinny

 

[iwire]

"Uh, your honor, I'd like to know whether the witness's testimony is opinion or fact!" ~ Mr. Trotter, D.A. ~ My Cousin Vinny

Just like the movie, my testimony is fact.

From GE

Normal Operating Sounds​

You may hear a pinging noise caused by water being picked up and thrown against the condenser on rainy days or when the humidity is high. This design feature helps remove moisture and improve efficiency.

You can find it here at the top of page 16.​

My own Pansasonic window unit has similar wording in it's instructions.​

Normal Operation

•You may hear a pinging noise caused by water being picked up and thrown against the condenser on rainy days or when the humidity is high. This design feature helps remove moisture and improve efficiency.​

​

 

[fbhwt]

"Uh, your honor, I'd like to know whether the witness's testimony is opinion or fact!" ~ Mr. Trotter, D.A. ~ My Cousin Vinny

iwire is exactly right by the evidence his has presented, when I was a youngster working with my father who was a heating and ac mechanic he told me about the fan and "slinger ring" on the fan and how it worked. You would be surprised how many people have drilled holes in there ac's, so much for reading the owners manual.

 

[hardworkingstiff]

"Uh, your honor, I'd like to know whether the witness's testimony is opinion or fact!" ~ Mr. Trotter, D.A. ~ My Cousin Vinny

That's one of my most favorite movies!

 

[fbhwt]

I should have said "when I was a ute"

 

[iwire]

Well, that would certainly explain the hostility.

 

[rruiz642]

GFCI and Window AC Fires

Well, taking a look at last years info there were 2,500 defective selector switches replaced by the manufacture out here.

We had a fire on Sat and one on Sun...both originated from the switch. Whether or not condensation is seeping in the enclosed swtich box, I couldn't say. But one customer heard popping sound, turned off the AC, the say sparks in/around the selector knob and then fire started.

Since I'm out here in the desert, the fans/blades get coated with fine dust. It was our former crew that had hope the GFCI would help reduce some of the fires. We know the GFCI breakers that we manufactured for us were inferior and we continue to have some blow then actuated or even the test button is exercised.

I just not confident that a AFCI or GFCI will reduce our obliviously HVAC problem.

 

[ramsy]

Just like the movie, my testimony is fact.

Nice find Bob. I also was sceptical of your original statement, which seemed plausable, but still suspect without the later evidence provided.

I still suspect GE did not implement its "sling ring" correctly. Before my drain hole, most of the water seemed to be slung perpendicular to air flow direction, sideways all over the inside of the unit (pinging sounds). However, the fan air flows to the rear, thru the condensor (aluminum radiator fins), not the sides on the unit.

On further inspection, I see iron oxide (red corrossion) on the fan shaft, compressor mounting bolt (bottom), and bottom frame screws (severe). I am not sure if the severity of this corrosion may have seen the unit fall apart shortly after the first year, without my drain hole, rather than lasting 3+ years now?

I would not recommend modifying a large or commercial AC with drain holes, but for GE windows units, if this design really was intentional, rather than an after thought placed in the troubleshooting section of the manual, then GE needs to remove the corrosive parts that remain incompatable with that design. Not sure about Panasonic.

Further, for much of the year in my area, we have problems with mosquitoes (West-Nile virus) breeding in standing water. I would rather not have that standing water behind the large vents of my inactive window AC, accessible to these insects during wet seasons.

 

[charlie b]

My guess: under-voltage is causing over-current and destructive temperatures, probably burning insulation..

Yea. What he said.

You are talking about an area that has far less control of its voltage on a system-wide basis. If you reduce the voltage on a motor, the current will increase. The I*2R heating will increase, and overheat the wire's insulation. That can set nearby materials on fire.

To directly answer your question, if you are looking for a way to prevent a fire from this type of failure, a GFCI breaker will be a waste of money.