Heater bearly heats house

[KevinLewis]

Ever since we moved into our house I have been trying to figure out what is wrong with our heater. For example it seems to run forever and not warm the house. It has run for four hours and not raise the temp from 60 to 64 degrees. The air coming out of the registers is luke warm at best. So far all I have been able to do is slow the fan down which helped a little. I have also changed the filter. The flame looks good, but I am not trained to look at furnace flames. I tried to check the temp rise but I used a infared thermometer and don't think it was accurate.



If i had too guess I would say its about 5 years old.



Any hints on what else I can check?



Thanks

Kevin

 

[fest3er]

You mentioned flame, so it must be gas; I'll assume natural gas, since proper dieselheads wouldn't use propane anyway.

Is the gas cycling on and off kind-of rapidly? There should be a sensor that opens when the temp gets too high. If it is cycling a lot, this means the system is not extracting heat very well. I had a blower motor die at my last house; the gas would ignite, temp would rise too high, gas would shut off; temp would drop, gas would ignite again.

Possibilities:

• gas pressure (or flow) is too low, preventing full flame; check the meter and shutoff valves
• fresh air to the burner is restricted, preventing good burning
• blower is too slow, preventing efficient heat transfer
• ducting is faulty (disconnected or blocked), preventing proper or adequate air flow

If *nothing* else has changed, I would first suspect the meter and supply to the house. Ask the gas company to stop by and check things out. They have great interest in making sure the gas system is in good working condition. They won't fix anything past the meter, but they will check for things that aren't right. And they should definitely verify that their meter is functioning properly.

 

[Dieselnut59]

What's wrong with a dieselhead using propane? When we live in a rural area, we have no choice for gas heating. I damn sure do not want electric and I have been happy with my gas heat, stove, water heater and clothes dryer, all of which are propane. Advantage to propane is I am not "tied" to one supplier and I can buy it in the warm months when it is cheaper and my tank holds enough to carry me through the Winter. I fill the 500 gallon tank in Fall and top off in Spring.

Do you have any other gas appliances? If they are weak also, it is your regulator. If not, you can check the line pressure and make sure it is at the proper pressure when the burner is on. The flame will be weak if there is not enough volume (indicated by low pressure when burner is running) to feed the flame.

My system is "dual fuel", which is an electric heat pump with gas auxiliary heat. When running in heat pump mode, it does not put out hot air, but when aux comes on (outside temp below 35F or heat pump cannot keep up with temp change), it puts out near 100F air.

 

[KevinLewis]

The flame is not cycling on and off, it is on consatnly. The fresh air to the burner should be ok because its wide open. Could the exhaust pipe be restrictive? The gas stove seems fine but somtimes there are orange/yellow flames. could that be low pressure? I think I will get the gas company over here. As far as ducting, it all looks intact but can't see inside it. can I use a manometer to check air flow?



Thank for the insite

 

[fest3er]

What's wrong with a dieselhead using propane? ...

I meant in the truck...

 

[Dieselnut59]

I meant in the truck...

OK. LOL No propane in the truck... Just diesel and cooking oil!



Yellow/orange flames can indicate low pressure.

Try this:

Turn the furnace off, then turn the stove on high. Observe the flame. Turn the furnace back on (wait for the burner to light) and observe the flame. If it goes yellow then, you do not have enough gas volume. The furnace takes more to run than all other gas appliances (water heater, clothes dryer, stove) combined. Low volume's effects will be most noticeable on the furnace's output.

 

[jeepit]

Check exhaust & intake venting. Disconnect at furnace and have someone drop a tennis ball from the outside the home. I had a nest of some kind in mine one year and that was the problem...

 

[PC12Driver]

What's the make/model of the heater?

 

[KevinLewis]

I will try both of those when I get a chance. thanks alot guys.

 

[KevinLewis]

I could not find the model number yet but it is a rheem. I did the stove flame test and could not even see the heater start by watching the stove flame.

 

[BDaugherty]

Take it apart enough to inspect the heat exchanger and possibly (depending on design) A/C coil. If one or both is restricted, the air will flow around it more than through it resulting in little heat transfer. Also, I would check the temp of the air right after it leaves the furnace. You may be losing all your heat in the ducts. If all else fails, call a pro. You'll recover whatever the repair costs by not having your heat running constantly.

 

[KevinLewis]

What's the make/model of the heater?

ruud uglh-05naur

 

[PC12Driver]

Hmmm, that's only a 50k btu unit, so depending on how big your house is and how much ductwork it has, it may be doing everything it can already.

Another question: is your a/c unit integrated with this furnace as well? I rented a place for a while in Arizona that had a stand-alone a/c unit, and when I needed to switch over to heat I had to move a dampener around to cut off the a/c and open up the ducts to the furnace. Maybe you're making heat but blowing it somewhere else.

Along those lines, the a/c compressor isn't running with the heater on, is it? A slight miswire at the thermostat could get everything running at the same time.

If the burners are lit evenly, you're making heat. We just need to figure out where it's going.

 

[KevinLewis]

The house is just under 1200 s/f single story. No A/C. Lots of insulation in the attic. It's not built on a slab. I am gonna turn the heater on and crawl around under the house to see if I can find leaks in the ducting. Is the blower for the burner suposed to run all the time?



Thanks for all the help. We have a baby due on the 19 and I don't want him or her to be too cold.

 

[PC12Driver]

Is the blower for the burner suposed to run all the time?

Yup. Since the exhaust is so cool on high efficiency furnaces, it needs help finding it's way out of the house.

 

[Skydiver]

Kevin, Be careful. Gas does not play around. Call the experts if needed.

 

[fest3er]

For what it's worth, if it's a high efficiency furnace, then it's likely to be a counter-flow design. That is, the cold return air is blown down onto the heat exchanger, thus extracting the maximum amount of heat from the combustion (coldest return air hitting the hottest part of the heat exchanger). With that much heat extracted, there's not enough heat left to cause sufficient rise in a traditional chimney. That's why HE furnaces are vented into PVC and horizontally (or so) piped outside and have forced flow via a blower. The outlet temp really shouldn't be much more than 90F or so, probably around the temp of the hot air being distributed.

The combustion blower should not run all the time; it should run when gas is burning and, I would suspect, for a short while afterward to clear the exhaust pipe of noxious gases and to cool the heat exchanger.

 

[daytripper63]

If all the supply registers are in the ceiling then it is most likely a upflow furnace, and if you do not have a concrete foundation is the return air duct ran under the house? if so it may be partially disconnected and sucking in the cooler outside air which is harder to heat than normal return air from within the home.

P. S. are you one of those people whom think your saving money by not running the heater when your not home?

If you let the home get cold with that little heater it will cost you as much if not more to try and bring the temperature back up in the home, reason is everything in the home holds temp, the furniture the walls the carpet etc and you have to heat it all back to temp. The best thing to do is find a REALISTIC temp that the unit can maintain depending on home insulation etc and not vary the temp when away from home by more than 4-5 degrees. The way equipment is sized now days with whats called a Manual J calc. the units are designed to maintain a temp not recover a to a temp.

If you have any questions feel free to p. m. me

 

[KevinLewis]

All the supplys are in the floor of all the rooms. the only cold air return is in the hall ceiling. I plan on crawling aournd under the house this weekend to have a look around.



I was one of those people that kept it cold all day and warmed it up when i got home. I tried the 4 degree swing and the house cooled off faster than it could stay warm!

 

[daytripper63]

If your return air duct passes through the attic be sure to check it very good to make sure it is not sucking attic air which may be cooler than room air and trying to heat it.

If your vents are in the floor then the only ducts under the home are supply air, I would look closer at the return air duct to make sure it is not sucking in outside/attic air.