Natural Gas Furnace

Questions about repairs and parts for Nordyne furnaces, air conditioners and heat pumps for manufactured homes including Intertherm, Mac and Miller brands. Click here for Nordyne parts.

Moderators: Greg, Mark

mark185
Posts: 10
Joined: Sat Jan 26, 2013 12:20 pm

Sun Jan 27, 2013 4:20 pm

We purchased our home in 2008, a couple of days ago it got colder and we turned the furnace up past 70, overnite woke up to 55 and furnace was still blowing. I reset "vent safety switch, went through sequence of operation, house warmed up to 65 and started blowing cold air again, and again and again! Also have a flash code of "one". I cannot get heating and cooling "PROS" out here to look at it because of the creek crossing and bad road, i was acually denied service also because it is a manfactured home, go figure? So i researched the problem and found out i had a restriction, I had the gas company check the well it is ok, I cleaned the intake and exhaust vents, the A coils, and made sure the floor vents were all open, no restrictions. I removed the inducer and found "rust pieces"? at the connection of the inducer and exhaust vent, and what looks like a brittle gasket stuck to the back of inducer housing itself.It does look like something belongs there. Doing more soul searching it appears that the inducer orface has a problem burning up on some modles "which closley matches my modle", and / or the vent safety switch goes bad. My question is does my modle require a orface on the inducer, and/or does the vent safety switch need replacing.I hope the next info will help with a part no., and where to purchase Thank-You for your time
INTERTHERM M3RL Series 90+ Condensing Furnace
UNIT MODLE NUMBER: M3RL0ABW
UNIT SERIAL NUMBER: M3A050602044
BLOWER MOTOR: 1/2 hp
FUEL TYPE: Natural Gas
Furnace Input: 80,000 (Btuh)
INDUCER: Fasco - no.702111379 - TYPE U21B - V.115 - A1.75 - 6 HZ CUST. pin 6219290 RPM 3450
LIMIT SAFETY SWITCH: L145F 62499 A0506 36TX16 6838


DaleM
Posts: 385
Joined: Wed Apr 07, 2010 10:07 am

Sun Jan 27, 2013 11:32 pm

YES you furnace does require an oriface on the inducer motor. Those are not pieces of rust but burned/charred plastic. Unfortunately they are still made of plastic. I do not have a part number readily for you. I will see if I can find one and post it asap.

mark185
Posts: 10
Joined: Sat Jan 26, 2013 12:20 pm

Mon Jan 28, 2013 8:07 pm

Thank-You for your time!! Dale

mark185
Posts: 10
Joined: Sat Jan 26, 2013 12:20 pm

Tue Dec 31, 2013 6:16 am

INTERTHERM M3RL Series 90+ Condensing Furnace
UNIT MODLE NUMBER: M3RL0ABW
UNIT SERIAL NUMBER: M3A050602044
BLOWER MOTOR: 1/2 hp
FUEL TYPE: Natural Gas
Furnace Input: 80,000 (Btuh)
Still having problems with limit switch on inducer. flash code "one" furnace "operatation of sequence" performs like it should, perfect, until desired tempature is reached then limit switch on inducer closes, flame turns off, blower keeps on running cooling down house. I have took off the door with filter, reset limit switch, started furnace and now the furnace will operate like it should, put door on and limit switch will close after desired tempature . I started looking for blockage in flues ran a drier vent chimney sweep through system found no blockage clean as a whistle, cleaned furnace and A coil, cleaned flame sensor it looks good, replaced all limit switches including fan limit switch, Drain tube is also performing
my conclusion is there is a blockage somewhere, or is leaking pressure in the system, where should I look or start to eliminate suspecting problems ?? and is there a diagram for the passages I need to investigate, please help cant get or afford a furnace man

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Greg
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Joined: Wed Feb 28, 2007 8:01 pm
Location: Weedsport, NY
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Tue Dec 31, 2013 5:44 pm

Mark, I am in no way a pro when it comes to heating systems but is it possible that a downdraft or wind may be the problem? It would give the unit the same pressure that a blockage would.

Greg
"If I can't fix it, I can screw it up so bad no one else can either."


mark185
Posts: 10
Joined: Sat Jan 26, 2013 12:20 pm

Wed Jan 01, 2014 5:13 am

Thanks greg for the tip , you know when I went to clean the "exhaust vent" I said to myself, why is there no vent cap for the pvc vent, one was never put on when the house was installed, and not mentioned any where in the manual, but one is for sale. I will let you know if it worked thank a lot!!

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Greg
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Posts: 5378
Joined: Wed Feb 28, 2007 8:01 pm
Location: Weedsport, NY
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Wed Jan 01, 2014 8:42 pm

You could just add 2 90* elbows to it and see if it helps, you wouldn't even need to glue them.

I have had Monitor kero. units shut down from wind coming in the exhaust, so I cant help but wonder if that could be your problem.

Greg
"If I can't fix it, I can screw it up so bad no one else can either."

1987Commodore
Posts: 383
Joined: Mon Oct 25, 2010 9:53 pm
Location: Steuben County, NY

Wed Jan 01, 2014 9:30 pm

I have a M3RL, and there is no cap on the exhaust. The intake has 2 elbows.

mark185
Posts: 10
Joined: Sat Jan 26, 2013 12:20 pm

Thu Jan 02, 2014 5:58 am

There is 2 90 degree elbows in the flu system, from furnace thru ceiling turns left along ceiling joist to bottom edge of roof, at soffit, turns up thru roof, they 12 inches apart, intake is 12 inches above roof with 2 90's turned down, and turned right, away from the exhaust, exhaust is 10 inches above roof straight up ( I slipped on a 6 inch extension to the exhaust to make sure the intake was well below the exhaust, they almost looked even and I thought the intake was drafting from exhaust) Did not work, still resetting pressure switch. On another note, when I replaced all the limit switches at once, the first time it worked with door and filter on the furnace, it cycled properly, the very next cycle, the limit switch on the inducer had to be reset. Probably should of done one at a time? I also trimmed the hoses at pressure switch, inducer, and gas valve, to make sure they were not leaking pressure. I replaced orface in the inducer and made sure it was clean, any other things I need to look at? any help would be appreciated

DaleM
Posts: 385
Joined: Wed Apr 07, 2010 10:07 am

Fri Jan 03, 2014 8:04 pm

About the only other thing you could check is gas pressure on the supply and demand side of the control valve. I would think that a problem like this though (gas pressure) would have shown itself sooner.

mark185
Posts: 10
Joined: Sat Jan 26, 2013 12:20 pm

Sat Jan 04, 2014 8:59 am

Natural gas is dirty, we are using gas directly from a well on my property, I have been told that the pressure will fluctuate, and the line is 600 lf with one coupling, may be leaking? the line is only 10 yrs old, but you would think the flame sensor would signal the furnace to turn off the fan with the door on or off, am I missing something? Thank you everybody for your input, please keep it coming, I don't want to miss nothing, before I will have to reinstall it, or replace it, If there is any body that could tell me about how to do some dynamic testing, on certain parts checking currents and loads things like that would be cool (probably have to go to heating and cooling school, or try to pay someone if I can get them to cross the creek up in my holler, and works on mobile homes) Schematics on the different parts maybe? I should know that would be impossible just thought I would ask again thank you everybody! Keep it coming!

1987Commodore
Posts: 383
Joined: Mon Oct 25, 2010 9:53 pm
Location: Steuben County, NY

Sat Jan 04, 2014 12:00 pm

Here's a link to a manual. I didn't read the whole thing, but I did catch that the pressure switch can be affected by a plugged condensate drain.
http://homeappliance.manualsonline.com/ ... /m3rl.html

mark185
Posts: 10
Joined: Sat Jan 26, 2013 12:20 pm

Tue Jan 21, 2014 12:33 pm

FIXED IT!! Removed Blower Assembly, Carefully used a shop vac with brush attachment, duct tape small flashlight to end of hose so as to not drop anything down there also duct taped brush attachment, cleaned coil for secondary heat exchanger, put back together

DaleM
Posts: 385
Joined: Wed Apr 07, 2010 10:07 am

Tue Jan 21, 2014 4:16 pm

Good deal Mark. I wouldn't have thought that assembly could/would get that dirty with a decent filter in place. I haven't run into that situation yet with any M3s but I'm sure the day will come. Thanks for posting your FIX to this problem.

mark185
Posts: 10
Joined: Sat Jan 26, 2013 12:20 pm

Wed Jan 22, 2014 6:21 am

Update; locked out again, after 2 hours, sucked out all drain vents with shop vacuum, then removed blower assembly, set end of shop vacuum up in exchanger, used compressed air to blow out secondary "gently" between coil fins, re vacuumed, put back together, lasted through the night, " with door and filter in place" I'm going to have to try and get a pro to pull it out, clean completely, which I understand it has to be "completely Disassembled" Folks keep the filters "clean, clean, clean! out here in the country hard to keep the mud outdoors anyway this is a great site and thank you Aberdeem for your help and having the parts I needed

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