[bpatterson007]

Hi, tried browsing around for an answer think I might have found one (leaning capacitor), but I'd like some more input from experts.

My grandparents have been in a mobile home for a long time on a farm, and their AC is just now starting to act up. They don't have a lot of money either and I'm fairly inclined with fixing things. Problem is I cannot find a schematic, book, manual, NOTHING, on this AC unit.

It's a brand Nordyne, model is msc36e. I Google it and find ONE result from a lady wanting the schematic also... so anyway.

The problem is the air feels fairly cold, but the fan will not start on it. The fan will just make this low buzz sound when I turn it on. However the fan will run like a champ once I give it a little spin with a paint stirrer. It spins very smoothly and freely when it's off and I manually spin it.

I took apart the top of the AC, it's an outdoor unit, turned off all power, and gave it a good cleaning. It had a lot of grass, leaves, etc, everywhere.

I can't make heads or tails of what's inside, I'm not really keen on AC capacitors. I'm assumming they look like rectangles, rounded off on the sides, with connectors at the top. Problem is there's 3 of them on there.

The smallest one has a brown wire coming from the fan motor, to the capacitor, and another brown wire from it's other contact running back into the capacitor.

The middle size one has wires going to the blower, and one wire running to the large capacitor. The large capacitor has wires going to the condenser.

I believe these are all 3 capacitors. Anyway...

What do I do?


PS I worked on about $20 million worth of military communications systems. I can handle those I can handle this I'm sure... but I have nothing to go off for reference material. So avoiding having a repair guy come out would be ideal (unless to recharge coolant, don't think I can do that myself with none of the equipment)

[hvac1000]

Find the fan capacitor or the combo fan and compressor run capacitor and replace it. Usually when the motor will not start up it is the capacitor.I do not have a manual for that old of a unit but this may help .


http://www.nordyne.com/Literature/710226.pdf

[bpatterson007]

Ok for the capacitor to replace I'm assumming you mean the one that is sort of in a loop with the fan motor.

The other two capacitors are for the compressor and blower, just one wire runs between those for some reason...

Is this something easy to check before replacing? I'm extremely comfortable with a multimeter, I'm assumming I'd test it running for a certain Ohm reading?

The Capacitor that's in a loop with the fan is a:
(Says this on it)

MARS 2
12908
5 MFD +/- 5%
370 VA 50-60 Hz
E232158

Either way, where would I go if I did need a replacement?

[hvac1000]

A heating / AC supply house
Grainger company.
OR do a search on Ebay like this there are plenty more buy it now there

5 mfd 370V Run Capacitor (NEW) LOW SHIPPING PRICE - eBay (item 320253130224 end time May-23-08 12:35:29 PDT)

[bpatterson007]

Thanks, I'll give that a shot since it's so dirt cheap, I'll follow up on here. Thanks for your input!

[hvac1000]

You will do OK. Just chop the power before changing and short across the to cap terminals with a screw driver before grabbing the wires to remove. Sometimes a cap will hold a charge. Better to be safe than sorry.

[bpatterson007]

Got the capacitor, works great turning the fan on now, but since I'm working on it, I noticed there are two other capacitors in there. Anyway...

I paid close attention today and noticed it took about... maybe 5-10 tried to turn the compressor on, I can tell it's trying because it dims the lights in the house for a split second...

Is this another capacitor issue possibly? I believe it may be since the fan capacitor I replaced was ancient and these other two caps looks just as ancient and I'm assumming one of those controls the startup energy for the compressor.

Any advice is always wonderful, thank you!

[hvac1000]

It could be another capacitor for the compressor issue OR
You might need to add a start capacitor kit to help start up the compressor
The compressor capacitor could be weak.
If it has a low pressure switch that can also be a problem. There are many items and possibilities
Check your wiring from the unit to the outside disconnect and then to the breaker box inside. A loose connection can also be a problem.

[bpatterson007]

Ok I'm going to check the wiring in the morning in the meantime I'm going to order two new capacitors to replace the other extremely rusty/old ones (something I pondered anyway). I mean... they're so cheap it's almost like, why not do it?

[T-Top]

Why are you ordering run capacitors when you can get them at any hvac supply house or company. If you have to order I would order a start assist for the compressor also. After you install it and the starting amps are more 60 amps and not starting - your compressor is bad. A stuck compressor will take out fan motors and run capacitors when it goes bad.

[bpatterson007]

Well I'd rather spend $12 on the capacitors online, than spend the money on gas for a 45 minute trip (each way) to a HVAC store, we live sort of remotely.

[T-Top]

That part I understand, but if your compressor dims the lights when it tries to come on it may be the start capacitor and or relay. That's the third capacitor your seeing it will wire to a 2 X 3 inch relay. If the run capacitor will not fix it, than your out a few more days until you can try a start kit. Good luck and thank you for your service in the military.

[bpatterson007]

You're quite welcome, hopefully it's nothing too serious, the only reason dimming the lights didn't bother me is well... my grandparents double wide trailer was put here in 1983, and it has the original wiring in the house and AC unit.