Intertherm furnace not hot enough

homebuff · Sun Dec 21, 2008 9:52 am

Hey Robert or Mark! Back again with a quick question. My Intertherm gas furnace is not getting hot enough. It is about 25 degrees outside here in Okla. & the flame inside the unit is not coming out strong like it should. The air from the registers is luke warm & not hot like it used to be. It takes a long time for it to reach a certain temperture. I was thinking of purchasing one of your gas regulators here & want to make sure it is the correct one. My model # is MGH-055-ABWN-06 on the unit housing. The model # on the regulator is 36C67 Type177. The part # is 6243700. I noticed you have 2 differant Rorbert Shaw regulators in stock & I need assistance on which one I need to purchase. By the way, My new blower I purchased a while back is working flawlessly. Thanks David!

Oh! Hope your staff has a very Merry Xmas & a happy & safe New Year.

homebuff · Sun Dec 21, 2008 10:46 am

I left out some important details. My home is a 88 model 16x80 Heritage with a v-style sloped roof. The duct system is ok with no leaks. The temp outside is 15 degrees & not 25 degrees & the wind is calm, which I would think would not make a big differance as long as my home is insulated well which it is. The furnace is still running & has been for about 1 1/2 hrs. now. The air from the registers is still just barely warm. It is getting a little warmer in here now. Maybe because my wife turned it down in the middle of the night to 65 degrees Its taking this long for it to get to a desired temperature. Still interested in purchasing a regulator though since the unit is so old. Thanks!

Robert · Mon Dec 22, 2008 12:00 pm

Hi David,

Gas Valve # 624583 can be seen and ordered through PayPal

from left side of page here :

http://www.mobilehomerepair.com/NordyneGas.html

Merry Christmas !!

Thanks,
Robert

homebuff · Mon Dec 22, 2008 1:48 pm

Thanks Robert for that info. I just wanted to add that the flame is coming out like a flame from a campfire or stove burner & not out like a blast of flame all around the lg. plate on top. Could I be right about my visual inspection of the flame? Along while back I had adjusted the valve to control the pilot lite down some cause the unit would cycle on at times while the thermostat was down to a lower settings keeping it from coming on & later was reading on here where this was anormal condition for it cause it has to expell the heat from the chamber. The unit performed ok for many winters ok up till now. I will go ahead & order the reg. soon as I get my income tax check & install it & see what happens. Thanks David!

Robert · Mon Dec 22, 2008 3:02 pm

Hi David,

You're very welcome, happy to help. Can't say about the flame without testing unit and seeing it.

Test return air temp at filter and supply temp at closest register to get temp rise by subtracting return from supply.

Compare it to ATR/Air Temp Rise rating on furnace data sticker to know what burner is doing.

Thanks,
Robert

homebuff · Mon Dec 22, 2008 3:07 pm

Thanks Robert will do. Happy Holidays David!

Robert · Mon Dec 22, 2008 3:37 pm

You're very welcome.

Merry Christmas !!

Take care and best wishes,
Robert

homebuff · Thu Dec 25, 2008 2:24 pm

Hi Robert! Hope you & your family are enjoying your XMAS time. I have some news for you about my furnace. My step son came over last night for the holidays & looked at my furnace & told me the heat from the registers was definately not warm enough to keep our trlr. warm enough. I agreed! It takes along time for the air to warm it up so the furnace stays running a very long time. he told me most likely the limit switch is at fault. He told me also the air was coming out too much causing the inside chamber was keeping the air too cool. He told me there was a way to go in & set the speed down & there had to be wiring procedure do it. He is taking courses for residential HVAC & he is highly certified to help me. I.'ve done some shopping from your site & found a limit switch (626292) which looks identicle to mine. After the new year, I will purchasing some more of your products. Enjoy your holiday. David!

homebuff · Thu Dec 25, 2008 2:41 pm

Robert I uploaded a pic of furnace identicle to mine so it would give you more info. It is in my pics. Could not remember how to upload it to the topic in the forums section.

Robert · Fri Dec 26, 2008 8:39 pm

Hi David,

If the burner is lighting, the limits are fine.

What speed is blower running in ?

Did you check the ATR as suggested earlier ?

Thanks,
Robert

homebuff · Sat Dec 27, 2008 9:31 am

Hey Robert I'm not too familiar on how to check the fan speed or the ATR. The furnace is turned off now since the weather here is in the 60's & 70's. Weird huh for this time of year. It keeps cycling on & off at long periods of time not at random.My step son said the air coming out of the register should be a 80 degree differance from the unit. The burner does lite but the flame is not burning the way it used to. The flame is has a bend to it. With the lid open while watching the flame & the the fan off & the flame is burning, the color is yellow & when the fan comes on the flame turns to a blue color. I'll get my digital beam thermometer & check the register temps. May need some help on how to check the ATR. I tell you what, I will try getting a pic of the flame & see if that will help. Thanks David!

homebuff · Sat Dec 27, 2008 9:41 am

Would the pipe on the roof have anything to do with it? Like a restriction ? The burner igniter looks all rusted up. Those things are not cheap if thats the problem. I've doing some checking on the web on how these darn units work. The fan speed may be my whole problem since my stepson said the fan seems to be blowing too fast on the heat setting. Oh! the wire I was telling you about when I bought the new fan motor, The one I wired nutted by itself was green & a large wire & it went to the med low blade connector inside the relay box on top of the blower cage. This wire is not connected to the motor. If you could, will you tell me how to upload pics to this board if its possible?

homebuff · Sun Dec 28, 2008 3:08 pm

I might add Robert, I believe I fixed my problem with fancoming on at times when the furnace is off. I read on your troubleshooting link about setting the thermostat setting from 3-4 & no lower than that cycle time & set it to 3 & it no longer goes on & off. The only thing about the link is it has no troubleshooting for a Intertherm but I assume there is not much difference in the two.

Robert · Wed Dec 31, 2008 1:14 am

Hi David,

Roofjack could have blockage or seperation and if so, would/could cause similar problems.

Anticipator setting at t-stat can also cause this. Look on gas valve or in homeowners manual for correct setting.

For ATR, take temp reading at furnace return air entrance at filter.

Then take temp reading at closest register.

Subtract return from supply to get ATR.

Blower motor should be wired to Low speed connection.

Don't have a clue on uploading pics.

Having door open will cause burner flame problems you stated.

Thanks,
Robert

homebuff · Wed Jan 07, 2009 7:12 am

Thanks Robert will do.