New Airstream - Air conditioner/Furnace problem

[mariffe]

Hello All,

After 2 months of anticipation I finally picked up my new to me airstream in West Virginia and towed it home to Wisconsin this weekend. It is a 1986 31' Sovereign with rear bedroom - side bath.

Although it seems to be in great shape - the furnace will not ignite and the air conditioner will not turn on. This is true whether plugged into shore power or not. (Oh - it may also be important to mention that the blower DOES come on when I am trying to start the furnace. The gas is on but the ignitor will not activate. Air conditioner does NOTHING. No fan, no heat,...)

My question is - could these problems be caused by a common electrical problem or do they seem separate and unrelated?

I checked the breaker box and no breakers were tripped - but maybe there are some 12v fuses that I am unaware of??? Do I need to activate any switches???

Thanks in advance for any help!

Matt

[thenewkid64]

Matt,

These are usally two independent systems.

Info that is needed to help you diagnoise the problems.

Is the AC themostat on the wall, and is it combined with the furnace one or are the seperate?

What brand of AC unit do you have?

Now for the shot in the dark answers.

On the furnace it may be as simple as a blown fuse. There is a 12 VDC panel somewhere in the rig. I am sure someone can point you to it. If not the fuse, and the furnace is a newer model, there may be a cut off switch on the furnace itself. lastly the wiring to the furnace may be unplugged at the furnace. If the blower does not spin up, then nothing else will happen.

On the AC you may have to tun it on at the celing before setting the wall thermostat to come on. Then the wall thermostat will regulate tempature and my also control the blower action as well.

The AC unit is AC only but may use a 14 volt feed to run the thermostat. If this 14 VDC feed goes bad the AC unit may not work.

[john hd]

matt

welcome to the forum! glad to see another wisconsinite on the site!

can't help you with the furnace right away. you may just have air in the lines, try it again.

as for the airconditioner, do you have a microwave? if you do, look in the kitchen cabinets for a household type light switch.

your microwave and airconditioner are on the same circuit, the switch prevents you from running both and overloading your 30 amp plug/service.

if you find a switch, put it in the other position and try your a.c. again.

john

[mariffe]

Thanks John and Brett!

My Airstream does have a microwave and I will look for the switch mentioned as soon as I get a chance!

(John, I live in LaCrosse but stay in Eau Claire during the week for work. I see you're not that far away.)

As for the Air Conditioner - it is the ceiling mount Coleman with thermostat on the unit. Previous owner said all worked well when he last used it - 2 years ago.

After reading some additional posts about furnaces it sounds as if the furnace could fail to ignite because of a low battery. Would a low battery keep the furnace from igniting even if I was plugged into shore power? Do I need to change the switch located behind the couch at the very front of the A/S to bypass the battery? Is that switch my Univolt?

Thanks Again!

Matt

p.s. I'll get my signature, profile, and picture updated soon so that you guys know who you're talking to about what! Thanks for your patience.

[john hd]

matt

the switch in front of your couch is the battery disconnect. all it does is disconnect the batteries from the 12v circuits in your trailer.

think of it as your master on/off switch for your 12v system.

i'm in madison btw. not that far!

john

[davidz71]

Matt,
Yes, a low battery will not allow the furnace electric fan motor to spin the fan wheel fast enough to trip the sail which allows the LP gas to enter the combustion chamber. Try hooking up to shore power and try again. I always light a stove eye to make sure that air is out of the main line then turn the furnace on. You may have an external shutoff under the trailer like I do. Make sure it is on. Listen near the unit for a clicking sound. It should try this at least 3 times then will stop if the unit fails to light. Do you have the Suburban furnace? According to my local RV mechanic, the 12 v. electric fan motor was on its last leg and it would not spool up high enough so it was replaced. I also had a bad circuit board which was replaced. The combustion chamber also had muddauber nests in it so it was cleaned out. Everything started fine after that but it was short lived. A bad thermo switch allowed the unit to overheat which effected the new circuit board. It was replaced free and a new thermo switch put in. Maybe some of these problems may point you toward your problem.

The A/C is on a seperate circuit on my '77 so John may be right about a seperate fuse somewhere. My A/C fan would come on but the compressor would not energize. I tracked it down to a faulty transformer that stepped the voltage from 120 to 24 (or was it 14) volts. It showed no voltage at the thermostat and only 9 right out of the transformer. Good luck.

[mariffe]

Thanks for the help Craig,

I'll try these and the other suggestions as soon as I get back home for the weekend!

There sure are alot of freindly and knowledgeable people on this boad. I'm sure it will be a great resource as I begin to get to know my Airstream!

I'll report on my findings next Monday.

Matt

[mariffe]

Well, it took longer to look into my problems than I had anticipated - but here is what I have been able to discover so far...

The furnace must have just had some air in the lines - because after boiling some brats in beer on the cooktop(Wisconsinites will know what I mean) - the furnace worked perfectly.

There must be some type of short or grounding problem with the electrical system of my trailer. Every appliance and outlet works correctly with the exception of the A/C.

I tested the power at the A/C unit and it was dead. I then fixed a "jumper" from a cut of extension cord to see if the unit would work and it performed wonderfully. (I know that this method does not provide ample amperage - but it did serve to prove that the unit will work.)

What really bothers me is that while doing some maintainance / cleaning on both the water heater and refer - I felt a small amount of current passing through the body of the A/S into my hand as I held open the acess panels.

I noticed that the extension cord I was using had the ground cut off of it by someone - could this poor ground cause one to feel a small amount of current passing through the A/S - or does my problem seem more serious?

Also - I looked into the breaker box trying to identify which breaker did what - specifically trying to isolate the breaker the A/C is on. I have three breakers. The top seems to control the power from the street, alternating current indicator light, etc.

The next breaker has two switches on it - and I think it controls the majority of the outlets.

Will the A/C be on its own separte breaker or will it be run with other appliances/outlets?

I checked all over the trailer for the switch that was mentioned to keep from blowing the breaker by running the A/C and microwave at the same time - but it is no where to be found.

What I am trying to avoid is having to pull out all of my cabinets, ceiling etc. to trace the power cord runnning to the A/C - but if it is possible that the wire is the culprit for the small amount of current I felt due to a short or mice chewing it - then I guess that is what I'll need to do. Anyone have any idea where the cord goes?

By the way - the A/S is an '86 31' Sovereign - side bath, rear bed. A/C is top mounted Coleman with its own thermostat built into the unit. Power cord to A/C unit goes into ceiling and seems to head to refer / micro on street side of trailer.

Any and all suggestions are appreciated.

Thanks,

Matt

[thenewkid64]

Before you start tearing things apart I suggest you do a little more troubleshooting.

First I would use a cord that offers proper grounding. Not just beacuse you could have a grounded wire, but because if in your testing there is a fault or major short you could get killed.

I would test your circuits as follows. Draw a rough outline of the trailer and map out the inside and outside outlets. With only the main breaker on see if any of them work using a meter or a portable 120 V Lamp. Then turn on one of the smaller breakers and do it again noting on the map what does or doesn't work. The flip on the second breaker and turn off the first one and do the same.

This will serve 2 purposes One is to see what is controlled by the breakers and the second is to identify if the breakers are any good.

It seems strange to me that you only have 2 actual breakers, usally the AC is on it's own 20 amp branch circuit.

The wire feed to the AC will run along the main longitudinal rib the lenght of the coach and then down inside the skin to the breaker panel. If mice damaged the wire they would need to be very thin and at this point very pink(from the insulation).

Do you have an open blank in the breaker box? It could be that the breaker had failed and was removed to take to the HW store to mathc up and never reinstalled. Just a wild guess..........

Good Luck

[mariffe]

Brett,

My A/S does have three breakers - Top is a single 2nd or middle has two switches on the same breaker, and bottom is a single again.

I did some testing with a meter at the outlets - but not in as organized a manner as you suggest. I'll take your suggestion and try to map out what does what - but I'll use my good extension cord with a ground this time :-)

Is there another simple way to simply test the breakers themselves? I'm thinking that maybe 1/2 of the middle breaker with two switches may have gone bad.

Thanks again,

Matt

[thenewkid64]

The only way to test the breaker is for continuity.

Without the rig connected to AC, pull the panel off the breaker box, there should be 2 or 4 screws holding it on. The breaker will have only 1 wire (or in the case of the dual one you have 2 wires) running to it. You can disconnect the wires and then just pull the breaker itself out of the box. Pull up on the end where the wires were screwed down. It should just snap out.

Now you can check it's continiuity.


If you have a single 3rd breaker I would bet it is the one for the AC. I would check it first before tearing any further into the electrical system. When they fail somtimes they look fine, but never really close. Hence no power.

[mariffe]

Thanks Brett,

That's what I'll do first. Sounds alot easier than tearing everything apart anyway!

[dmac]

While you have the power disconnected and the breaker out -

- Check the breaker for continuity as mentioned earlier
- Check for continuity in the wire from the box to the A/C unit itself using an ohmmeter

If both check out good, then with the trailer plugged-in carefully test the voltage at the breaker itself (at the screw where the wires attach).