Gas and Oil Home Heating Furnaces - HELP! Confusing Coleman Evcon Furnace

Just found this site- looks like a good one. I have a furnace problem that is driving me crazy so this is my last resort before calling an HVAC service and dropping lots of cash. Mobile home furnace, Nat gas, Coleman Evcon, about 10 years old, Model DGAT070BDD, Recall was done years ago (Heat exchanger lining). Got into the thirties here last night so I turned on the furnace for the first time this season. Turns on ignites- nice blue flame- blower is blowing fine but air out of vents is cold even in the next room which is inches away from where the furnace blows down into the duct??? No codes flashing. I removed the burner to inspect and it looks fine. It was fine last season, I just can't understand why it all seems to be working fine but I'm getting only cool air out of the vents. I do have a central air unit but it is self contained and has nothing to do with the furnace. Any suggestions cuz I'm going crazy.:wall:

Is the central A/C perchance running? Don't trust the thermostat, go out & actually look.
Does the flame stay on?

With only the furnace using gas (range, water heater, dryer, etc. not running except for pilots if so equipped), go out & look at your gas meter. There should be a dial marked 1/2 cubic foot. It should take about 40-45 seconds for this dial to make a complete rotation. Check & post back with results.

A/C not running. Flame is stays burning. 1/2 cubic foot dial one time took 2 minutes for full rotation- the next two times were 1:36 and 1:38. I'm thinking you are thinking gas valve not completely opening?? I thought about that and although the flame looks good to me- I can't compare because I've never really looked before and am unsure how intense it should be. Now here is one for you. In August I got a letter from WEPCO (gas+electric) that told me that my gas meter had been malfunctioning since January and that I owe them 400+ dollars for estimated use. They have since put a new meter on. One of my thoughts was maybe the valve that they shut off when they changed the meter may be bad and not opened all the way internally, it is turned all the way. Or could another bad meter restrict flow? The needle does not steadily turn, kinda jumpy at times, jumping a quarter turn at times. Is that normal. Before last season they put the meters that can be read remotely. The first one was bad- maybe this one is too but would that restrict flow?? Only other gas usage is water heater and that seems to be working fine.

You are only putting into the furnace about 37,000 btu/hr instead of the 70,000 it is rated for based on 1,000 btu/cu. ft..

If you are sure that dial is 1/2 cu. ft. & not 1 cu. ft./rotation, take the burner apart. There is a stong possibility a spider or other insect got in there, built a nest, & is restricting the gas flow. As I recall, that furnace has a single orifice which screws into the gas valve. behind that orifice is a favorite nesting place. Let me know.

Thanks Grady, you are awesome! Sure nuff, spider sac in the orifice. Got some flameage now. Now the 1/2 cubic foot dial takes about 30 seconds for a rotation- is that okay? I`ve got another quicky for ya, the notice sticker they put on when the recall(update) was done says to not close off any vents or block with furniture or could cause damage. Now I've had a dresser over half the vent in a bedroom for years and I also like to partially close the bathroom vent which is next to the furnace because it blasts out of that one and leaves me with not much volume out of the kitchen vent which is all the way in the front of the mobile home but increases when bathroom is partially closed. I`m not getting how this could cause damage- close one and it comes out of the others. Should I not be doing this?

Sounds a little quick but I don't know the exact btu content of the gas in your area nor the pressure at which the furnace is set. In any case, you're a whole lot closer now than before evicting Ms. Spider. First time I encountered ye olde spider nest it about drove me nuts until I pulled the orifice. ;)

As long as the dresser is off the floor where air can flow from under it, you should be fine. I wouldn't worry about the others.