Massive Heat Wave, AC not working. - HELP

OK so I woke up this morning and the AC was still running. Just to recap, I still have the original roof unit that came with my 2005 Fifth Wheel.

Yesterday, the control box and the thermostat were both replaced. I now have a digital control box and a digital thermostat from Dometic. When he installed all of this, he set the fan to Auto and the unit to cool and it worked from 3pm yesterday through the entire night.

When I woke up this morning, I simply change the thermostat up to around 72 degrees so that it would shut off for awhile while I got ready to leave. It kept running and would not turn off. Either fan or compressor.

I then just switched the unit to the off mode. IT shut off. I let it sit for a minute or two and then switched fan to Auto and unit to cool. During this time, the temperature had increased in the coach so I decided to set thermostat below room temp to see if it would come on. Compressor did, but the fan did not.

I did the thermostat reset as outlined in the manual, but that had no effect. The only way I can get the fan to blow is to set it on high and then turn on cool and it works perfectly.

My question is, is this normal given the equipment I have? Prior to this, I had an analog thermostat, and when I switched to cool with auto on the fan, both came on at the same time.

Any help is appreciated. BTW, I contacted the RV Tech that installed it and let him know what happened. If he needs to come back out, I do not think I should have to pay another service call fee to come out to diagnose/fix something he did right?

It was the control box. Basically, totally black on the other side of it. So I got the wiring right, in the end but by then I did the damage.

AC is blowing cold with a strong fan, and I have a digital system. Feels good. Probably fee better after the sun has gone down. It's going to take awhile to make it cold in here.

I called the mobile RV repairman. Can't get here until tomorrow afternoon. However there were some very encouraging things about this fellow that I haven't even met yet.

1. They were very careful to ask me what the problem is.
2. They asked me what all I had done and observed.

(Note: I have to come clean on something that I didn't say before. When I initially got everything together this weekend, remember that I said that I forgot the order of wiring into that plastic plug connector? Well, the first time I hooked it up, the fan and the compressor came on together, but when I would adjust the fan speed, it would never change. It blew cold air. So I decided to, without any pics taken prior, or looking at the instruction manual, to do what I thought was best.

I fired up the fan and I heard and saw a spark come from the control box. My guess is, I fried that fan circuit on that board.)

I just want to apologize for not mentioning it earlier after seeing everyone trying to help me. I was embarassed.

3. They think it's the control board too. Bad news is that Dometic does not manufacture the analog boards anymore. Yes you can get them, but they are hard to find. Thus, I will be getting the new Climate Control Center and a digital thermostat.

4. All of this is likely to set me back, parts and labor, $250.00 in addition to the $150 I spent on the fan motor from this weekend. Still, that's less than half the cost of a brand new roof unit, and even if I bought a new one, if the control board fries, nothing is going to work.

5. With the new control box, should I need a new roof unit, it will be as simple as removing the old one, and putting on the new and plugging in.


I'll let you all know how things evolve from here. Many thanks for all the guidance, help, and patience. I do apologize for not mentioning that little nugget before, but again, I felt a fool for doing it.

The new AC units are about 10 lbs lighter. NOT that much easier in regards to weight when lifting up and removing the old:B Doug

PS, I thought you had a Penguin model(600 series). Your pic shows a Brisk Air (500 series). So, my comment about the penguin motor was not correct for your AC unit

Walaby wrote:
My .02 cents... you've been battling this for a couple of days and it's roasting out there. It would be worth the $75 for someone to come out and take a look at it. I think $75 is more than fair. A typical house call for A/C around me is $125.

Mike

Thinking I am agreeing with you on this. I have learned a lot more than I knew before, which was nothing, on how these things work.

1. I could buy a new rooftop unit. But if the control box is malfunctioning, I will be back in the same boat.

2. Rooftop AC's are expensive. Like really expensive!

3. Rooftop AC's do not seem that difficult to install, and the new Dometic ones are a lot lighter and more efficient.

4. I got reacquainted with my multimeter and various methods of measure electrical voltage. It had been awhile.

5. In the search for what is causing my problem, I found out that another Dometic product I have, which is the fridge, is part of a voluntary recall where I can get it fixed free of charge! I might use that as a bargaining chip with the service guy cause he will get paid from Dometic to put the fix in.


All in all, RVing has been eye opening, and frankly, if I had the income, I would just travel all over this country. Right now I am stationary while we build a house.

My .02 cents... you've been battling this for a couple of days and it's roasting out there. It would be worth the $75 for someone to come out and take a look at it. I think $75 is more than fair. A typical house call for A/C around me is $125.

Mike

dougrainer wrote:

motc777 wrote:

j-d wrote:
Your wiring looks right, given the two RED wires are on HERM and BROWN is on FAN.

I was mistaken earlier and will correct that post in EDIT: With the Dual Capacitor, COM should have 04 wires and I had said 03. Then 05 wires if you jumpered to a single FAN Cap and I had said 04. Since there are only 04 lugs on a capacitor terminal, the extra wire could go to the terminal on the single cap that you connected the jumper to.

I've heard of OP's shooting control box trouble down to a relay and they getting a relay from an electronic supply house. Even Radio Shack might have something.

I'll go look at that Control Box page on Chris Bryant's site. Here it is Linked

Hey take a look at page 16. It talks about a mechanical on/off selector switch. It says to "The air box should still be off. The electrical box needs
to be dropped from the template and switch cover removed.
Disconnect the wiring from the switch, (be
sure to note wire location for proper replacement),"

I have no idea what they are calling the air box. As for the control box in the ceiling, there are some relays, but they are all soldered onto the board.

The AIR box is the silver galvanized housing for the Circuit Board. The "Mechanical" switch/s is actually 8 or 9 DIP switches on the board that you turn on or off depending on the configuration of the AC/Heating system. Doug

OK That's what I thought. I didn't see any dip switches on the board.

Someone mentioned about calling out a tech. I think I might have found one, but the service call fee is $75. Is that fair? I only ask because I have not be RV'ing that long so I don't know a lot.

I am wondering if it may not be worth it to have someone that is highly experienced take a look, just to make sure that the troubleshooting I did is right, so I don't order a part and have that turn out to not be the solution? What do you all think?

This person came highly recommended by an RV park down the road that has called him for nearly 20 years. He's local and they say he knows what he's doing. Just wondering what the panel here may think, or should I just get a control box and do it myself?

motc777 wrote:

j-d wrote:
Your wiring looks right, given the two RED wires are on HERM and BROWN is on FAN.

I was mistaken earlier and will correct that post in EDIT: With the Dual Capacitor, COM should have 04 wires and I had said 03. Then 05 wires if you jumpered to a single FAN Cap and I had said 04. Since there are only 04 lugs on a capacitor terminal, the extra wire could go to the terminal on the single cap that you connected the jumper to.

I've heard of OP's shooting control box trouble down to a relay and they getting a relay from an electronic supply house. Even Radio Shack might have something.

I'll go look at that Control Box page on Chris Bryant's site. Here it is Linked

Hey take a look at page 16. It talks about a mechanical on/off selector switch. It says to "The air box should still be off. The electrical box needs
to be dropped from the template and switch cover removed.
Disconnect the wiring from the switch, (be
sure to note wire location for proper replacement),"

I have no idea what they are calling the air box. As for the control box in the ceiling, there are some relays, but they are all soldered onto the board.

The AIR box is the silver galvanized housing for the Circuit Board. The "Mechanical" switch/s is actually 8 or 9 DIP switches on the board that you turn on or off depending on the configuration of the AC/Heating system. Doug

j-d wrote:
Your wiring looks right, given the two RED wires are on HERM and BROWN is on FAN.

I was mistaken earlier and will correct that post in EDIT: With the Dual Capacitor, COM should have 04 wires and I had said 03. Then 05 wires if you jumpered to a single FAN Cap and I had said 04. Since there are only 04 lugs on a capacitor terminal, the extra wire could go to the terminal on the single cap that you connected the jumper to.

I've heard of OP's shooting control box trouble down to a relay and they getting a relay from an electronic supply house. Even Radio Shack might have something.

I'll go look at that Control Box page on Chris Bryant's site. Here it is Linked

Hey take a look at page 16. It talks about a mechanical on/off selector switch. It says to "The air box should still be off. The electrical box needs
to be dropped from the template and switch cover removed.
Disconnect the wiring from the switch, (be
sure to note wire location for proper replacement),"

I have no idea what they are calling the air box. As for the control box in the ceiling, there are some relays, but they are all soldered onto the board.

Your wiring looks right, given the two RED wires are on HERM and BROWN is on FAN.

I was mistaken earlier and will correct that post in EDIT: With the Dual Capacitor, COM should have 04 wires and I had said 03. Then 05 wires if you jumpered to a single FAN Cap and I had said 04. Since there are only 04 lugs on a capacitor terminal, the extra wire could go to the terminal on the single cap that you connected the jumper to.

I've heard of OP's shooting control box trouble down to a relay and they getting a relay from an electronic supply house. Even Radio Shack might have something.

I'll go look at that Control Box page on Chris Bryant's site. Here it is Linked