Modine Big Dog problem

[sgo70]

Hi guys,

I'm new to the site, I was just looking for help fixing my furnace when I found this one. Of course I got distracted and started browsing through all the threads and found some really interesting topics. Gonna have to look into one of those lifts.

I live in Calgary, Canada and spend a lot of time in my shop working on different projects. Currently I'm just finishing up on a '31 Model A Hotrod with a '51 Chev pick-up next in line. As I said in Canada we really need our heat so here goes.

I have a Modine Big Dog that has worked great for a year or so until recently. The fan was staying on blowing cold air almost constantly. Now the blower and the flames will run but the fan doesn't come on. I disconnected the fan and tested it and it worked fine. The green LED is blinking constsntly so I can't figure out any codes and I can't see any breakers or reset switches. I also pulled off the vacuum line and sucked through it, it feels like the switch is moving inside. There is an on/off switch but I think it is for the gas.

Any help here would be much appreciated,
Sean

 

[sgo70]

I went out to check today and I was getting six flashes on the LED, indicates a system lockdown. I reset the gas valve and gave it another try, this time I got four flashes indicating limit control or flame roll out switch open????

I followed the wiring diagram and figured it might be the heat sensor in the tube assembly, I tried cleaning it but no luck. I took it out and I think I'll try to find a new one and see if this helps.

Any input would be appreciated,

Thanks,
Sean

 

[sgo70]

Well, I called in a service guy and he charged me $110 to look at it. At first he said the fan was shot and I told him I tested it and it was good. So then he told me it was the control board and it would cost another $450 minimum to fix. I told him to get lost, paid his $110 and started calling around.

I came across a very helpful guy at Alggin Metals that really seemed to know what he was talking about, nice change from what I've been getting lately. He told me to bypass the fan and it worked, so he said it would be the control board and he had one for $85. I brought it home and rewired everything up, took about 15 min. It's running now as per normal, I'm just waiting to see if it shut's off as well.

Hopefully this can help someone else out and they won't have to pay the service fee.

Sean

 

[russlaferrera]

Glad it worked out for you. I read your post but had no honest input to give.

 

[mulepackin]

Thanks for posting your follow up here. Glad to hear it has seemed to work out. I've got a 75K btu unit and have had great luck with it. I've not had any problems since I installed it so didn't have anything constructive to add either.

 

[sgo70]

Thanks anyways guys, I searched google for hours and found nothing so I didn't expect too much. Kinda hard to diagnose over the internet unless you've seen it yourself.

Now about those car lifts..........


Sean

 

[Junkman]

I'm curious why you didn't call Modine and ask them. A call from Canada to the US has to cost a lot less than $110 for someone that hasn't an idea of what they are doing. I would have thought long and hard before giving him $110 when he had no idea of what he was doing. Probably would have handed him a $20, and told him to have a good day. I have no tolerance for someone that holds themselves out as an expert, but is totally incompetent. If he is a licensed HVAC guy, I would report him to the licensing bureau. He deserves $110 worth of aggravation for what he did..

 

[BigMike782]

I am waiting on my SECOND fan control board for my Hot Dawg heater.