Coleman DGAA mobile home furnace issue

baluna · 04-05-2012, 04:49 PM

Here's the situation:

I have a coleman DGAA furnace in a 1971 mobile home. The mobile home was built in 1971 and we are located in Massillon, Ohio. We are experiencing okay weather right now but tonight it is supposed to drop to 32 degrees.

For two weeks now I've been through hell and back trying to get someone from an HVAC company to come out and repair my furnace. Apparently nobody wants my business because nobody has returned my calls or responded and the one company that was supposed to return did come back today a week after the diagnosed the problem.
ACCORDING to them the problem is the gas valve is not working. However, they cam in to replace it only to find out that the gas valve that IS on there was welded on. Well the company that came out today to fix it is the same company that put the damn thing in to begin with. When I bought this mobile home the furnace was installed already.

Anyway when I first turned the heat on over here back in January I got 3 flashes from the circuit board so I bought a new pressure switch. I replaced the pressure switch and cleaned out the tubes. Well I still got 3 flashes regardless of which pressure switch was in the thing. So I called my friend who does HVAC repairs and he said to buy a new circuit board. I bought a new circuit board, turned everything on and got 1 steady flash. Well I thought it was the hot surface ignitor and so I bought one. Big mistake because according to the HVAC guy that I called from the company that installed the furnace....the ignitor is fine if the glow coil is glowing.

When I turn the furnace on and put the thermostat on it goes through its checks, the inducer comes on, it does some more checks, the glow coil glows, does some more checks, it all shuts off and starts over again. Sometimes it bypasses and blows cold air through instead of hot. I have the thermostat set for heat at 80 degrees but it still just blows cold air. The sensor was cleaned and there's no dust in the furnace or around it at all, in fact the HVAC guy came and cleaned the furnace to be sure.

I haven't reconnected anything, the gas valve is still disconnected and I am almost tempted to go in and reconnect everything to see what happens.
I have 2 small children one is only a toddler the other is a newborn. I won't let my kids be cold even if I have to sacrifice everything but it still sucks being cold, myself and we could really use the heater tonight.

Here are some pictures

Right now everything is disconnected because the HVAC professional that DID come in left everything disconnected and I have since left it that way. Its been a week since the first HVAC pro disconnected the gas valve from the furnace.

Should I try reconnecting everything to see if I get a new diagnostic code sense the sensor has been cleaned? The sensor was only recently cleaned a few days ago. I don't know what to do and none of the "pros" are helping. I was wondering if I could troubleshoot the gas valve instead of having the HVAC people return and charge me AGAIN

I posted this at another forum haven't received responses. If more info is needed please tell me and I will gather it.

**beenthere** · 04-05-2012, 08:23 PM

I'd remove the orifice, and look to see if a spider made a web in it.

REP · 04-05-2012, 11:59 PM

The gas valve is niot welded on.The side outlet is part of the gas valve.It is a gas valve made by White Rogers especially for Coleman.
They brought out the wrong valve and are just BS ing you to make themselves look good.In my mind they failed.
If you google white rogers gas valve 36e29-101 you may be able to get one online.
If you need it today then you have to get it at a local Coleman distributor .
My suggestion is that you call a better contractor and give them the info before they come out.
If the first contractor was wrong about the valve being bad then you have invested nothing.Let the new contractor invest in getting it and if not needed it should be easy for him to return it.

Doc Holliday · 04-06-2012, 01:04 AM

GarryE · 04-06-2012, 09:58 AM

Stop! Doing too many things at once. Lets go back to the first issue, 3 flash trouble code. Is that a pressure switch issue? I don't remember if this one has one or two lines going to it but pull any line off of the pressure switch and try to blow through it. Sometimes your neck isn't long enough to do that so then trace each one back to where it comes from and remove it from the fitting and try to push a wire or tooth pick through the fitting so you know that it is clear. Inspect the line that you have removed, look for cracks breaks or splits, reinstall it. If there is another, do the same thing, make sure it is clear. Now, retry the furnace. OOPS. The valve is off, right? Are you comfortable reinstalling the valve? If you are, put it back on then do that other check. Do you hear a click or clunk in the gas valve about 15 seconds after the igniter heats up indicating the valve is opening? If not further electrical troubleshooting is necessary to make sure that current is actually being passed to the valve. I think I would stop right there. Mobile home furnaces are a different breed of cat and a lot of contractors don't like to work on them. I would call a local mobile home dealer or your local gas company and get a recommendation for a servicing dealer from them to someone who specializes in mobile home furnaces. Many times there are companies who specialize in all types of mobile home services that are very reasonable in price and know what they are doing with them.

REP · 04-06-2012, 01:17 PM

Quote:

Originally Posted by GarryE

Stop! Doing too many things at once. Lets go back to the first issue, 3 flash trouble code. Is that a pressure switch issue? I don't remember if this one has one or two lines going to it but pull any line off of the pressure switch and try to blow through it. Sometimes your neck isn't long enough to do that so then trace each one back to where it comes from and remove it from the fitting and try to push a wire or tooth pick through the fitting so you know that it is clear. Inspect the line that you have removed, look for cracks breaks or splits, reinstall it. If there is another, do the same thing, make sure it is clear. Now, retry the furnace. OOPS. The valve is off, right? Are you comfortable reinstalling the valve? If you are, put it back on then do that other check. Do you hear a click or clunk in the gas valve about 15 seconds after the igniter heats up indicating the valve is opening? If not further electrical troubleshooting is necessary to make sure that current is actually being passed to the valve. I think I would stop right there. Mobile home furnaces are a different breed of cat and a lot of contractors don't like to work on them. I would call a local mobile home dealer or your local gas company and get a recommendation for a servicing dealer from them to someone who specializes in mobile home furnaces. Many times there are companies who specialize in all types of mobile home services that are very reasonable in price and know what they are doing with them.

GarryE just for your information,mobile home furnaces are exactly the same as any other furnaces.They operate the same,there is no differance with the blower system,absolutely the same as any other.
The only differance is that mobile home furnaces have what is normally called a direct vent system where combustion air is brought in from outside the home so as not to use all the interrior air of the home.
They do this with a metal fitting .It has nio moving parts and no control wiring to it.This is the only differance in a "mobile home furnace".

baluna2 · 04-06-2012, 02:00 PM

sorry i was having difficulties logging back in so i created a new account. Ever since I replaced the control board, whenever it cycles through, the LED code flashes 1 flash which according to the legend means failed to ignite. So I guess its back to the gas valve.

baluna2 · 04-06-2012, 02:01 PM

Since the orifice is welded onto the mounting plate and the mounting plate is then welded to the gas valve i will need to get a new mounting plate?

baluna2 · 04-06-2012, 02:17 PM

Okay the gas valve and everything is disconnected because the first service tech that came by disconnected everything but this is what they did:
checked for and cleaned any spiderwebs, cleaned the furnace out like for dust and other common problems and then diagnosed that it was the gas valve that wasn't letting gas in? Anyway I am not sure how to reconnect everything at this point. I will probably end up buying a new gas valve because this gas valve the orifice is welded to the mounting plate which is welded to the gas valve and i dont know how to unweld something. I don't even know how to weld and my friend is a welder and will do that part of the job when i get a new mounting plate?

GarryE · 04-07-2012, 09:55 AM

Sorry that I haven't gotten back to you, I was gone the rest of the day. The only replacement for the valve is a direct factory replacement. This is what I meant when I said that they are a different breed of cat. You cannot use off the shelf components for some of the parts. I'm not sure where you live but I'm betting there is a Johnstone Supply not far from you. Look them up and find a location near you, they all have 800 phone numbers. They are Coleman Evcon Distributors and can supply those parts for you or send you to a reputable dealer to find them. Have the model and serial number of the furnace and all of the numbers from the tag on the gas valve in front of you. They will provide you with the correct part ready to install. One caution, when you install the valve you must use a manometer and set the correct gas pressure to the burner. This is very important and must be done. Speaking of gas pressure, has anyone checked the supply or incoming gas pressure? Be sure that reading is taken before installing the new valve. If it is more than 8" w.c. for natural gas or 14" w.c for LP your regulator must be reset or replaced. If the supply gas is above those levels the valve will automatically lock out and the new valve could be ruined.