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Limit Switch Part# for MGH-055-ABWN-06 furnace

Posted: Sun Jan 06, 2013 4:10 pm
by homebuff
This model is an Intertherm/Nordyne down flow gas a/c central unit.

Just had the motor replaced & back up & running again.
The only issues I have with it now which it had before is the unit in the heat mode only & not the a/c mode it cycles on & off about three times in short cycle's till it stays running & puts out some heat out of the registers.
The heat is not real hot like it used to be a long time ago when it was running normal.

The only part i need now to make it cycle normal is the limit switch.
Two of them in the parts list "676235" & "626292" look like mine in my unit.
The one in the unit now is an old part number that I have in the past had problems getting the correct one.

Need some support from Robert or Mark on this problem getting the correct Limit Switch.
I got with Robert a long time back about finding the correct Limit Switch.

Help me Robert or Mark find this switch so I can purchase it from you soon to get my furnace to cycle correctly so I can heat my home.

I can get the part number on the limit switch if needed.

Thank's! :D
David

Re: Limit Switch Part# for MGH-055-ABWN-06 furnace

Posted: Tue Jan 08, 2013 12:15 pm
by DaleM
Look on the limit switch for a temperature rating. Usually stamped on the metal ring around the switch. The real question is why is it cycling on limit. For some reason it is tripping the limit switch which is a safety device to prevent an overheat sutuation. You need to find out why the furnace is running so hot.

Re: Limit Switch Part# for MGH-055-ABWN-06 furnace

Posted: Wed Jan 09, 2013 8:00 am
by homebuff
DaleM wrote:Look on the limit switch for a temperature rating. Usually stamped on the metal ring around the switch. The real question is why is it cycling on limit. For some reason it is tripping the limit switch which is a safety device to prevent an overheat sutuation. You need to find out why the furnace is running so hot.
It doesn't appear to be overheating cause the air coming out of the registers are a little warm & not how like it's suppose to be.
The limit switch is posted in the Nordyne furnace parts section here as part # "626292"
Cost around $90.00 to purchase after tax & shipping.
L130-15F limit disc Red face
F110-20F Fan disc Orange face
I tried uploading to here but says it's too large over 256Kb's.

Re: Limit Switch Part# for MGH-055-ABWN-06 furnace

Posted: Wed Jan 09, 2013 8:08 am
by homebuff
I read on one of the posts some of theses models had a shield over the limit disc keeping the fan from blowing on it but I see no such shield ever being attached to it.
The Flame stays lit all through the on off cycling about three cycles before it stays running till the flame shut off then fan stops after it cools down till it starts all over again when the flame starts up again when the house cools down a bit.
On the third & final on cycle it bangs real loud like the fan cage housing is loose.
The upper two threaded bolts holding the cage on the unit are tight.
I was also told to check the vent cap for possible bird nest causing a heat restriction.
Been planning on getting up there to check bit it's been raining here.

Re: Limit Switch Part# for MGH-055-ABWN-06 furnace

Posted: Mon Jan 14, 2013 11:31 am
by DaleM
If the flame is still running then the limit switch is functioning correctly. The limit switch cuts power to the control valve on the burner assembly. It will not effect the blower circuit. Sounds like you may have a spider web in the main burner oriface. A small fire will cause the blower switch to cycle quickly when the furnace begins heating up. You will need to pull the burner assembly, remove the oriface and look to see if there is a partial blockage. Sounds to me like you're only getting about 50% gas flow.

Re: Limit Switch Part# for MGH-055-ABWN-06 furnace

Posted: Mon Jan 14, 2013 11:52 am
by homebuff
:D Thank's!
I did clean the orifice out a year ago by taking the whole burner out & had some crusty stuff on it but no webs.
I'll remove it again when the weather warms up a bit where we don't need heat.
I always suspected the flame to be incorrect when it's burning & it dances around instead of a full flow of flame & has a yellow flame instead of a blue flame.
The heat coming out of the registers is just warm & not hot.
It blows out strong air.
First I was wondering if the roof vent was restricted.
It's bent down on one corner a bit but can see inside the cap.
Hard to see if it has any cracks in the chamber but does have some of those round burned (hot) spots on it.
Any tips on what to use to clean the orifice out effectively?
I may have my a/c heat guy come back out & visually check the flame himself just to be sure before & remove the burner assembly.
It comes on while the burner is on a couple a times for about 5 seconds then shuts down then comes back on for a bit longer till the 4th time it comes on & stays running with the burner active.
As I mentioned before it makes a loud banging noise once the motor turns on & much louder on the 4th time it stays running.
I am intending on getting another limit switch anyway once I get my SSI check from here.
Might even consider getting another complete burner assembly from here too once I find the correct one.
I believe its a a White Rodgers brand.
Thank's for offering me support. :wink:
Let you know how it turns out.

Re: Limit Switch Part# for MGH-055-ABWN-06 furnace

Posted: Mon Jan 14, 2013 12:11 pm
by homebuff
Is it possible I could use a welders tip cleaner instead of a pipe cleaner? :?:
I have two of these.
I can't seem to find the whole burner on here. :(
Intertherm model "MGH-055-ABWN-06" type "W" burner
possibly a RobertShaw brand.

Re: Limit Switch Part# for MGH-055-ABWN-06 furnace

Posted: Thu Jan 31, 2013 12:11 pm
by homebuff
My MGHA Intertherm unit has a metal box surrounding the limit switch completely enclosed with holes made in it on each side & on the bottom.
No way a plate had broken off on my model the way it's designed.
Thank's for any input! :D

Re: Limit Switch Part# for MGH-055-ABWN-06 furnace

Posted: Tue Jun 11, 2013 2:11 pm
by homebuff
:( Found out when I purchased a new rebuilt limit switch from here it did not fix my issue.
Still having to use floor heaters to keep the house warm in the winter.
No need for it now though.