Drastic variance in temp

I have a Coleman Model G9T06010UPB13C furnace, installed 2007.

We just purchased the house and I noticed that the air coming out of the vents on one side of the house is drastically warmer then the other.

Air temp coming out of the east side vents is at least 15 degrees cooler than the west side vents.

The duct works come straight off of the top of the furnace, plenum is large enough for an A-coil but doesn't have one (no central a/c) then tees off going east and west. If you place your hands on each side one is really hot the other cool.

No damper in either side of the tee (just in the take offs), there is a humidifier that disconnected but still attached.

Here is a picture of the plenum coming out of the top of the furnace, attached is the humidifier that is not connected to the return and has been capped and sealed awaiting removal.

There is a tee attached to the top of the plenum as I mentioned before. There is no damper in either side of the plenum.

All of the rounds coming off for both sides of the house have dampers and all the registers have dampers also.

Temp out of the left side (marked with X tape) taken at first take (disconnected at spin in and used digital thermometer) off 3' from the x is 61 degrees.

Temp out or right side (plain tape) taken 41" from the tape is 88 degrees temp taken with the same method.

Thanks in advance for your knowledge.
Willis

I hate to say it but, your best bet is to open up the duct work and find out what is diverting the heat to one side.

check location of cold air return

nealtw said:

check location of cold air return

Click to expand...

There are two cold air returns. One in the library and one in the living room (the two coldest rooms in the house). All other rooms have 3/4 removed from the bottom of the doors to allow for a wild return.

Bathroom has an exhaust fan of course but that is neither here nor there.

By looking at your pic. i don't see anything wrong. Have you looked inside your furnace
when it going to make sure all the burners are burning. On some 90+ furnaces half the burners on one side could be burning and not on the other side. If this is not whats going on then
cut a good size hole in the plenum so you can look down at the top of the furnace to see
if the baffles are out of place. later paul

ye it sounds like you have to have a close look at the furnace. was it like this for a long time or is this new . You could pull a pipe apart on the cooler side to see if an open hole would change conditions at the furnace. this would indicate plugged pipe near the register. Like toys or somesuch, or insect nest??

nealtw said:

ye it sounds like you have to have a close look at the furnace. was it like this for a long time or is this new .

Click to expand...

We just bought the house in September so I am not sure how long this has been an issue. The people here before did not make an attempt at quality repairs.

nealtw said:

You could pull a pipe apart on the cooler side to see if an open hole would change conditions at the furnace. this would indicate plugged pipe near the register. Like toys or somesuch, or insect nest??

Click to expand...

If it was just one register I could see that, but there are is a total of 6 registers off of the cooler side and every one of them is blowing the cooler air.

I have taken each pipe run off and cleaned, checked for dampers, and sealed them with pro- seal on re-installation.

I am hoping to pop off the humidifier today and look inside, I will get some pics up when I do.

Thanks to everyone for you time thus far.
Willis

here are some pics of the interior of the plenum. No deflectors or obstructions that I can see that would cause the problem.

Anyone else have any other ideas?

Thanks
Willis

can you have a look at the fire when it is running. wondering if some jets are not burning.