Replaced both of the capacitors. Still doesn't run.
Fuse is good.
Is there something else I can check or call a pro?
Looks like a new board is about $150.00.
Does the fan run?
When you switch the thermostat to cool, and drop temp setting well below ambient can you hear the compressor trying to start?
Is it only one ac unit or both that are not working?
Hey Chuck -
The fan does not run - even with help.
I did not leave the unit energized long enough to see if the compressor started. Will try that tomorrow afternoon.
We have 3 units. Front, Middle and Rear. The Front and rear stopped around the same time. I replaced the capacitors in the front ac unit and it is running. The middle unit is running fine. The problem child is the rear one now. The front and rear ac units were replaced by our PO in 2011.
Are you getting power out of the control board?
Thanks to Steve and Michelle as I found the wiring diagram in OUR Library.
And sedelange....
Next opportunity I will get my DVM and start to follow the power. ARGH
And do you have 120VAC to control board?
Pretty rare for an ac to not show some signs of life, fan turning slowly, or running only with spin start etc. Sounds like a control issue board most likely, or 120V supply.
Will try to follow the power path later today. Got stuff to do this morning.
Ours has a 12v blade fuse on top under the cover for the controller
Checked that blade fuse. Appears to be good.
check power going in and out of switch first
Neither fan or compressor start. Taking up DVM now.
Called Dometic and spoke with tech support. They advised to replace the board and if still not functioning, replace the unit.
Guess I'll get new board.
Scott,
But you HAVE confirmed 120 VAC to the board?
12 VDC signal from thermostat?
No I have not but will before I order new board.
Thanx for your input.
where is coach now ? I will be at wolf creek park this weekend I can look at it for you I work on them rooftops.
We are in Magnolia, TX. Great offer but you appear to be quite away.
Is it worth the effort to switch out boards between your units? If the problem follows the board, you know you need to order a new one. If it doesn't, keep troubleshooting.
Good thinking. Might give that a try. 👍
well if you have troubles let me know I live in conroe/woodlands just taking my MH to the lake this weekend for a car show
We will be on Lake Conroe also starting Sunday afternoon @ 1000 Trails.
I don't know, but if they make one, I'd buy a 'Dinosaur' board. If it's not the board, it's always good to have a spare! ^.^d
There may be jumpers or dip switches that tell the thermostat which board to talk to for Zone 1, Zone 2 etc. You might also experiment with switching those or reversing the wiring to rule out a dead zone on the thermostat.
Mine had a wiring diagram on the inside of it. That was key to finding that the terminals in one of the connectors to the board was not making good contact.
Thanks all. Will try to get up there tomorrow. Today did not turn out like I expected. 😊
Energized the unit from the thermostat.
Disconnected and reconnected com. cables above the white interior vent cover. Tried to touch contacts in the male comm connector and saw no life.
How do I verify signal from the t-stat?
Was able to verify 121 vac into control board.
Saw nothing coming out.
Is there a fuse on the control board?
Well, I guess I fixed it. It is operating now - fan and compressor. I did not replace the Control Board.
After I verified that 110vac was going to the board, I pulled all spade connections apart and and reconnected all. Just for the heck of it I went to the t-stat and energized the unit again after I turned OFF Zone ! and 2 heat.
Is it possible that the t-stat can not operate one zone in Heat Mode and one in Cool Mode?
Anyway, it is operational.
Thanks to all for providing suggestions as to what I could try to diagnose and "fix" the non-functioning roof ac.
In the next day or two I will hit all of those connections with some dielectric material.
I will check the capacitors that I replaced to verify that they are NFG. If not I have a couple of spares.
I believe they will not do heat and cool at the same time.
If that is the case I might have learned something new.
My ignorance sometimes overwhelms me. :))
I have discovered that mine will not operate with AC in one zone and furnace in one of the other zones as well.