Furnace heats, but cool/warm air at registers
#1
10-05-05, 10:49 AM
Furnace heats, but cool/warm air at registers
My wife and I recently bought our first house. It has started gettting cold here and this morning I turned on the gas furnace. I set the thremostat at 68 (it was 63 in the house). More than an hour later, the temperature had not raised even one degree. The furnace fires and heats up well, and there is good air flow at the registers, but the air at the registers, even the ones closest to the furnace, is just barely warm. The furnace is an old Rheem, I would guess mid-70's, because that is when the house was built. We are already planning to replace the furnace with a new, more efficient one, but we need heat in the meantime. We had a similar problem in the summer when we first moved in; we could run the A/C all day and the temp would not drop even though there was cool air coming from the registers. We had the option of opening the windows and turning on fans then, however. Anybody have any idea what this could be?
#3
10-05-05, 11:22 AM
Originally Posted by Jay11J
Did you check to see if you have flame on all the bars on the burner area?
The heat collector (?) get so hot that you can't touch the outside of the furnace.
Somehow the heat is disapearring before it gets to the house.
#5
10-05-05, 04:42 PM
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Something is up... if you are not getting much heat.
Where is the return pulling from? where is the duct work for return coming from?
Fan maybe on too high, but still should have some warmth.
Where is the return pulling from? where is the duct work for return coming from?
Fan maybe on too high, but still should have some warmth.
#6
10-05-05, 06:25 PM
Originally Posted by Jay11J
Something is up... if you are not getting much heat.
Where is the return pulling from? where is the duct work for return coming from?
Fan maybe on too high, but still should have some warmth.
Where is the return pulling from? where is the duct work for return coming from?
Fan maybe on too high, but still should have some warmth.
I had a professional out last week and he said everything appeared to be in operating condition. He ran the furnace, but he didn't wait around for a couple of hours so we did not know that the air coming from the registers barely heated up. I don't need another service call charge, so I am trying to figure this out on my own. If it just involves the duct work or something fairly simple like that I can fix it.
It seems to me (not knowing that much about HVAC) that somehow the air is bypassing the heat exchanger since everything in the furnace seems to working. Or that somehow the hot air is getting mixed with cold air before it gets to the registers. The closest register is only about 6 feet away and the air from it is only slightly warm.
If it is the fan too high, how can that be fixed?
#8
10-06-05, 11:25 AM
Originally Posted by Jay11J
Take a temp reading at the return/air filter side of the furnace, and just pass the a/c coil.. See what kind of temp rise you have.
I grabbed a small thermometer and took a reading by the blower where the air comes in. It was at room temperature, around 65 to 68. I couldn't see how I could get in past the coil while in the house, so I tried going under the house to check. I could not find a good place there either, but I felt the plenum (?) and the ducts leading from it. The ducts were cool to the touch and the plenum was slightly warm. I went back into the house and checked the registers and I was surprised to find fairly warm air coming from all of them.Then I turned off the furnace. A few minutes later I turend it back on but once again all that came out was the cool/warm air. I decided to leave it on for awhile.
I went outside to check on a tree I had just planted and while outside I heard something running I went around the corner to find that the A/C compressor was running while the furnace was on.
I think this could explain what the problem is, both in summer and winter. The only thing is, is that I don't know what to do about it.
I did replace the original stat when I moved in with a new digital programmable one. I was thinking this may have something to do with the problem.
#9
10-06-05, 02:15 PM
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Turn off the power, and check the wires on the t-stat.
You should have Rc and R(h) jumper together tied to R on the furnace itself.(red)
Then Y should be by itself going to the fan center screw to the outdoor unit.(Yellow)
now the (color) may be diffrent. you'll have to go to the furance to make sure that where that color is going to match the letter.
You should have Rc and R(h) jumper together tied to R on the furnace itself.(red)
Then Y should be by itself going to the fan center screw to the outdoor unit.(Yellow)
now the (color) may be diffrent. you'll have to go to the furance to make sure that where that color is going to match the letter.
#10
10-06-05, 05:51 PM
Originally Posted by Jay11J
Turn off the power, and check the wires on the t-stat.
You should have Rc and R(h) jumper together tied to R on the furnace itself.(red)
Then Y should be by itself going to the fan center screw to the outdoor unit.(Yellow)
now the (color) may be diffrent. you'll have to go to the furance to make sure that where that color is going to match the letter.
You should have Rc and R(h) jumper together tied to R on the furnace itself.(red)
Then Y should be by itself going to the fan center screw to the outdoor unit.(Yellow)
now the (color) may be diffrent. you'll have to go to the furance to make sure that where that color is going to match the letter.
There are three sets of red and white wires (one red, one white). The first set comes from a small transfomer near the blower, the second set comes from inside the blower compartment and the third set comes from the outside compressor. The red on the first set is connected to the red t-stat wire. The white on the first set is connected to the white coming from the blower compartment (second set) and to the white coming from the compressor (third set). The red wire coming from the blower compartment is connected to the green wire on the t-stat. The red wire coming from the compressor is connected to the blue (yellow) wire coming from the t-stat. The white wire coming from the t-stat is connected to a terminal on the gas unit.
I hope I have made this clear enough to understand. It took me a little bit of looking to get it figured out.
Is one of these wires not where it is supposed to be?
#11
10-06-05, 09:13 PM
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The red on the first set is connected to the red t-stat wire.This is your power to R at the stat
The white on the first set is connected to the white coming from the blower compartment (second set) and to the white coming from the compressor (third set).This is your common side.
The red wire coming from the blower compartment is connected to the green wire on the t-stat.This is wire to turn blower on and off from t-stat
The red wire coming from the compressor is connected to the blue (yellow) wire coming from the t-stat. this is your power to turn on compressor outside
The white wire coming from the t-stat is connected to a terminal on the gas unit.this turns the gas valve on or off
It sounds like everthing is wired up right..... Try to undo the "Y" at the t-stat and turn on the system again and see if the outdoor unit starts up again.
The white on the first set is connected to the white coming from the blower compartment (second set) and to the white coming from the compressor (third set).This is your common side.
The red wire coming from the blower compartment is connected to the green wire on the t-stat.This is wire to turn blower on and off from t-stat
The red wire coming from the compressor is connected to the blue (yellow) wire coming from the t-stat. this is your power to turn on compressor outside
The white wire coming from the t-stat is connected to a terminal on the gas unit.this turns the gas valve on or off
It sounds like everthing is wired up right..... Try to undo the "Y" at the t-stat and turn on the system again and see if the outdoor unit starts up again.
#12
10-07-05, 07:48 AM
Originally Posted by Jay11J
The red on the first set is connected to the red t-stat wire.This is your power to R at the stat
The white on the first set is connected to the white coming from the blower compartment (second set) and to the white coming from the compressor (third set).This is your common side.
The red wire coming from the blower compartment is connected to the green wire on the t-stat.This is wire to turn blower on and off from t-stat
The red wire coming from the compressor is connected to the blue (yellow) wire coming from the t-stat. this is your power to turn on compressor outside
The white wire coming from the t-stat is connected to a terminal on the gas unit.this turns the gas valve on or off
It sounds like everthing is wired up right..... Try to undo the "Y" at the t-stat and turn on the system again and see if the outdoor unit starts up again.
The white on the first set is connected to the white coming from the blower compartment (second set) and to the white coming from the compressor (third set).This is your common side.
The red wire coming from the blower compartment is connected to the green wire on the t-stat.This is wire to turn blower on and off from t-stat
The red wire coming from the compressor is connected to the blue (yellow) wire coming from the t-stat. this is your power to turn on compressor outside
The white wire coming from the t-stat is connected to a terminal on the gas unit.this turns the gas valve on or off
It sounds like everthing is wired up right..... Try to undo the "Y" at the t-stat and turn on the system again and see if the outdoor unit starts up again.
When I went to the t-stat I saw that there were 2 terminals for yellow, one labelled Y1 and the other Y/O. When I installed it I just put the wires in the same order that they had been on the old t-stat (matching the colors, of course). I moved the wire from the end terminal (Y1) to the 4th terminal (Y/O) and everything works fine.
Thanks for your help!
