Replacing air conditioner capacitors

[steve2777]

Had similar problem after a shore power problem. Replaced the caps and still didn't work. Looked at the circuit board and found it scorched. Replaced it also, and unit works good as new. Got caps on Amazon and circuit board from another online vendor. Process was easy "plug and play" and all parts cost under $160. I would give it a try.

[makemglow]

Originally Posted by steve2777

Had similar problem after a shore power problem. Replaced the caps and still didn't work. Looked at the circuit board and found it scorched. Replaced it also, and unit works good as new. Got caps on Amazon and circuit board from another online vendor. Process was easy "plug and play" and all parts cost under $160. I would give it a try.

where might yhe circuit boatd be?

[Sunny1]

Originally Posted by makemglow

where might yhe circuit boatd be?

Inside your RV look up into the ceiling assembly under the AC and you’ll see it. Everything is plugged into it. Google Coleman Mach circuit board and look at images and you’ll see what it looks like.

Last year my rear AC wasn’t working. If I recall the compressor wasn’t kicking on, so I replaced the capacitors, and that didn’t help. I ended up replacing the unit, and then decided to go ahead and replace the front unit also so I wouldn’t have the main AC fail while out camping (their age was circa 1998). Not really all that difficult to do yourself if physically able to work on the roof, and if you have some help getting the units up on the roof.

Personally if I were you I’d replace the capacitors and maybe the circuit board if it looks damaged, and see if that fixes it. If not then you’ll have some spare parts for your new AC unit.

[makemglow]

Originally Posted by Sunny1

Inside your RV look up into the ceiling assembly under the AC and you’ll see it. Everything is plugged into it. Google Coleman Mach circuit board and look at images and you’ll see what it looks like.

Last year my rear AC wasn’t working. If I recall the compressor wasn’t kicking on, so I replaced the capacitors, and that didn’t help. I ended up replacing the unit, and then decided to go ahead and replace the front unit also so I wouldn’t have the main AC fail while out camping (their age was circa 1998). Not really all that difficult to do yourself if physically able to work on the roof, and if you have some help getting the units up on the roof.

Personally if I were you I’d replace the capacitors and maybe the circuit board if it looks damaged, and see if that fixes it. If not then you’ll have some spare parts for your new AC unit.

replaced start capacitor and all is well. doesnt quite keep the beer cold but the rig cools down as it should. $50.00 about.

[cavie]

Originally Posted by makemglow

motor has a long shaft with blades in a shroud. has to get air from somewhere to blow inside.

the unit gets air from inside the trailer and blows it thru the AC and back into the trailer. No outside air involved''

[bobmac]

Get the owners manual or preferably the Service manual for the A.C. unit and get the specs for the three capacitors. They are rated in micro-farads (uf or Mfd) and have an operating voltage spec - 370v for my Coleman basement Air. Caps fail on their own with time so it is not likely - but possible- that other parts have failed. Check the circuit board for evidence of damage - if there is other damage new caps won't likely resolve your problem.
You can get the caps at an appliance parts store or an electronics parts store. You can go with an equal or higher capacitance rating and an equal or high operating voltage if the exact ones arent available - you cannot go lower. Costs for the three should be about $30 if pirates don't run the store. They are easy to replace although you will need to replace burnt wiring and supply new crimp connectors for connection to the caps. You don't need OEM caps - just caps with the proper rating.
For a $30 investment, you have little to lose and an older unit is likely better built than a new current model. If you are uncomfortable working with the wiring, get an "electrical handy" friend to give you a hand. Being able to purchase and install spare caps is a tremendous and valuable skill set for an RV owner and will pay off many times and insure you are never without a working AC if you carry spares. This skill set can also be very valuable with your home Central AC when it wont start saving you an expensive service call.Good luck,

[marjoa]

Originally Posted by triplewide

Three capacitors, sounds like you may have had a "hard start kit" installed on the AC. Check the wiring diagram, if still visible. May only require 2 capacitors.

HUH?

We have 3 cap's on both our A/C's and no hard start kit. OEM.
Fan Capacitor
Start Capacitor
Run Capacitor

[Mallie]

Originally Posted by bobmac

Get the owners manual or preferably the Service manual for the A.C. unit and get the specs for the three capacitors. They are rated in micro-farads (uf or Mfd) and have an operating voltage spec - 370v for my Coleman basement Air. Caps fail on their own with time so it is not likely - but possible- that other parts have failed. Check the circuit board for evidence of damage - if there is other damage new caps won't likely resolve your problem.
You can get the caps at an appliance parts store or an electronics parts store. You can go with an equal or higher capacitance rating and an equal or high operating voltage if the exact ones arent available - you cannot go lower. Costs for the three should be about $30 if pirates don't run the store. They are easy to replace although you will need to replace burnt wiring and supply new crimp connectors for connection to the caps. You don't need OEM caps - just caps with the proper rating.
For a $30 investment, you have little to lose and an older unit is likely better built than a new current model. If you are uncomfortable working with the wiring, get an "electrical handy" friend to give you a hand. Being able to purchase and install spare caps is a tremendous and valuable skill set for an RV owner and will pay off many times and insure you are never without a working AC if you carry spares. This skill set can also be very valuable with your home Central AC when it wont start saving you an expensive service call.Good luck,

Bob,,you can go with a higher voltage rating, but not a difference in capacitance. Has to be exact.

[triplewide]

Originally Posted by marjoa

HUH?

We have 3 cap's on both our A/C's and no hard start kit. OEM.
Fan Capacitor
Start Capacitor
Run Capacitor

May be different on yours. Here is picture of wiring diagram on my factory 15k BTU (same on 11k BTU that I added):



Here is a picture of the capacitors on my 15 K BTU:



Capacitor on the left is the run capacitor, middle is the fan, one on left is the "hard start" I added. I used the Positive Temperature Coeficient Resistor type.

Top left corner of diagram indicates that the dashed line items are optional. Maybe your coach manufacturer included one of these options in their "OEM" version.

[96 Wideglide]

Originally Posted by Gary RVRoamer

I'm trying to figure out how blown capacitors caused smoke to come out inside the RV. There is no air path from the exterior (where the capacitors are) to the inside ducting. There is only a heat exchanger. If you had white smoke inside, I'm thinking something more serious than the caps happened. The caps may have failed because of some other problem, e.g. really high voltage (as might happen on 50A power with a open neutral wire).

When one of my start capacitors blew, I could smell it inside the coach. Didn't see any smoke, but could certainly smell burned electronics!!

[Bob_C]

When you pull the shroud, and replace the capacitors, why not protect your units by adding aluminum screen door screening to the inside of shroud vents.....keeps all flying critters out and no nests being built on the fans.....