Frigidaire Window Airconditioner Unit - Inop

[Toranaga]

Guys, I need some advice. Got one of those "buddy" jobs and don't quite know where to start. My friend has a heating and cooling window unit bought from Lowe's last November. I am guessing it is the model number listed above, or very similar, I have not sen the machine yet and he has no paperwork. (its in a rental unit). Anyway, the unit is completely dead, no heat, no cool, no lights. I suspect and electrical problem and will approach it from that direction as I don't do CFC work. Here's my train of thought

1. Check the breakers, fuses and outlet.

2. Check the power cord and terminal for VAC

3. Check the PCB for signs of a blow up.

4. swithches/ touchpad etc.

5. ???

I understand how compressors work, but I'm not qualified to replace one.

Any advice?

Normally wouldn't take this job, but its for a real friend - the kind that helps you hide the body.

T.

[RegUS_PatOff]

LRA18HMT20 Parts List & Wiring Diagram

[Toranaga]

Thanks Reg, Wiring diagram is pretty simple. How does the overload relay work? If it trips, can it reset?

T.

[RegUS_PatOff]

How does the overload relay work?

looks like a standard Compressor overload . . (automatic)

but would only control the Compressor

[Toranaga]

Well then barring any house wiring problems, I'm likely looking at a bad board, huh?

[kdog]

Well then barring any house wiring problems,

Pretty common issue with portable A/C units, they're a big power draw - have them try another outlet that is known good before you head out

[Toranaga]

Good advice, Kdog. Thanks.

[appl.tech.29501]

Most of those units have a reset on the power cord....pretty common for the to go bad....have changed a tone of them....verify voltage at the power board.

[Toranaga]

Most of those units have a reset on the power cord....pretty common for the to go bad....have changed a tone of them....verify voltage at the power board.

Will do, thanks!

[Toranaga]

Cords good. Outlets good. Correct model number is LRA12HZT2. How much voltage at the touch panel? I get 120 at RY4, P9, and RY6/4. Nothing at RY7/3 which leads to the compressor. No activity at the display board. What next?

[Toranaga]

Ok. The on off button is on a pcb. I get continuity when I press the button. But it shuts off when I release ot. Shouldn't it stay on till I press it again?

[kdog]

I get 120 at RY4, P9, and RY6/4.

Should have 120 at RY6-4(hot) and P8(neutral), if you have that and no activity, you have a failed PCB - compressor failure does not affect fans/display eyc.

[Toranaga]

Summary:

The main board gets voltage 120 VAC. The Display board gets about 7 VAC through a ribbon. But does not respond to user input. I see no evidence of any bad solder joints or burns on the display board at all. I could use a little help. Thanks. One more wierd thing I noticed. Although the cord delivers power tot he unit, the "test" button doesn't seem to have any effect. i press it and the unit still gets power. Hit reset and nothing changes.

T.

[kdog]

The main board gets voltage 120 VAC.

Thats the only job of the powercord, whether the GFCI part is functional or not - you need to be sure the voltage is measured at those pins (R6-4 and P8), if it is there, it means that something is not switching within the PCB and it is likely FUBAR

[Toranaga]

Thanks Kdog. That's about what I thought. I was torn up about the fact that there is some voltage getting to the smaller display board - about 7.2 VAC. I'm gonna recommend replacing the cord too, just for safety, I guess.

[Toranaga]

New twist. The label calls for 230 volts but there is

only 120 at the outlet. Checked breakers. All good.

[kdog]

only 120 at the outlet.

Yes, the document that Reg posted shows unit is 230v, needs to be a double breaker - shut them both off and on again as one side may be tripped

[Toranaga]

Right. Put the meter on every breaker. 120 on all. 120 at the wall. 120 at the board 240 NOWHERE. What am I missing?

[kdog]

One breaker has to come from the RED side of the box and the other from the BLACK side to get the 240

[kdog]

240 NOWHERE.

Try and reset the Main (100 A) breaker - that should affect mant other items in the home though if it were tripped

[Toranaga]

No red side. Two blacks. Old house. All breakers have power. DANG! Even the plugs only wired for 120!

[kdog]

Has this unit ever worked ??

[RegUS_PatOff]

has this A/C worked at this location up till now ?

Is this a standard 240v Wall Outlet ?

post picture of Wall Outlet and test points ?

[kdog]

I have been called out to New dryers in older homes that don't work to find out they only have a 60A service that cannot support a double 240v breaker, oddly enough they were always replacing old gas dryers