Repair help for the do-it-yourselfer.
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Moderators: Mark, Greg, mhrAJ333, JD

Posts: 6
Joined: Sun Mar 15, 2015 10:39 am

Desperately need assistance with an "intermittent problem"and hope somebody can provide guidance. Have a good to strong background in mechanical/electrical theory since I was in the Navy serving aboard submarines. Served 26 yrs, now retired, trying to fix my furnace! ahahahah :D

2010 Intertherm M3RL080A

Problem: Intermittently works or "fire" ON. Bought mobile in 0ct 2013, warranty after 5 yrs?
LED code : 4 blinking lights

What I've done:

Replaced flame probe, after I cleaned it 10x, bought a new one, still same 4 led code
Replaced thermo-switch (reset-able), only popped once all winter, bought NEW
Sent a camera up the intake/exhaust pipes since I found 4 bees in the furnace burner box. Snaked both pipes and a small 1" hive fell out. The top of the pipes have a screen mesh.
Replaced batts, NEW thermostat when I moved in.
Reset the CPU, power ON/OFF the whole winter, froze some nights, but it worked intermittently to keep house at 65f. Both my kids are fine when they were here, just more blankets.
Slipped intake pipe off the burner box 1" for more AIR to burner, nothing
Propane tank was 80%, worked good, now 35% problem?
Propane Vv seems to work in proper sequence, yellow, orange flame, snuffed out and wont stay lit for flame senor to acknowledge . Again intermitant, sometimes it works 1st time!!!!
Downloaded the Tech Service manual - 200pgs - read it front to back ---10x !!!!!
Reviewed the flow chart in tech manual for 4 blinking lights, probe or bad ground.
Tightened all ground screws, re-seated all modex connections, and all board connections.
Cleaned some surface rust on burner box, all surfaces solid metal.
Checked all forms online and related problems.
Call a tech, he said its intermittent and cant diagnose unless we keep replacing parts, CPU, Gas Vv are next. $$$$$$$$$

HELP plse........ Sorry fer the blabbering....Will check on this group weekly or if my email address is required will phone also. Thanks SubGuy26yrs Dave
Posts: 110
Joined: Sat Oct 08, 2011 11:39 am
Location: Brazil, IN

8000 Phoenix Pkwy, O'Fallon, MO 63368
(636) 561-7300

Be a squeaky wheel.

Posts: 180
Joined: Thu Mar 15, 2012 11:04 am
Location: Western Washington, Puget Sound

Hey subguy, me too. Only 8 yrs, was a nuke.
Posts: 6
Joined: Sun Mar 15, 2015 10:39 am

Thanks UmpJJ, its a start. Steve-WA - still have the same problem today?

UPDATE: The past 4 days have been good, the problem has not occurred? Hmmmmmm?
The last thing I did was reseat all the connections, and molex plugs. Standby...
Posts: 6
Joined: Sun Mar 15, 2015 10:39 am

Seems maybe reseating "ALL" the connections and modlex connections maybe fixed it? I'm still watching it closely, but furnace only cycles 2x a day since its warmer out. Hopefully in Oct it will start up without any problems. :D
Posts: 6
Joined: Sun Mar 15, 2015 10:39 am

Well, its been 2 weeks and the furnace seem to be "scared" and has started every time without incident. Guess replacing the flame probe, limit switch and re-seating ALL the connections has proved successful. I saved the service call and a tech who was going to replace the CPU and gas-Vv if things didn't work. Got the propane tank filled, I'm ready for the Fall season. Hopefully things will fire-up and run normally. Will keep tabs on this form and hopefully everyone can find answers to questions. Thanks, Dave
Posts: 6
Joined: Sun Mar 15, 2015 10:39 am

Just a quick update. Upon some in-depth inspection under the mobile I noticed that the drain pipe was NOT straight to allow the water to drain correctly. It was in a KNOT !!! Yes a KNOT prob from the factory. All the water was built up in the line, maybe had sometime to do with pressures or a drain prob.??? Who knows but plse check everything, as I did. Well, lets see what happens in Nov ! Thanks All !
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Joined: Wed Feb 28, 2007 8:01 pm
Location: Weedsport, NY

I would really LIKE to say it surprises me but if read much he about what some people find it really doesn't.

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