What I learned about the furnace - Montana Owners Club

Montana_70 · 02-10-2006, 08:03 AM

I decided to do a little more research on how the furnace operates. I have learned the sequence is the Power Switch, Thermostat, Sail Switch, Relay Switch, Limit Switch and then the Circuit Board.

Took off the air vents inside and looked around. I don't think there is anyway to get to any parts without removing the furnace itself. That's what Keystone service says too. They advise against it if you don't know what you are doing.

The calls to repair people have been the same answer, "you need a new circuit board". What I have learned, doing a little research, is that many good boards are replaced before checking out the sequence of the system for more minor problems. Keystone's guess is it is my Limit Switch because I'm not hearing the furnace try to ignite.

There is not a space heater to be found around here.

When it gets cold in FL those seldom thought about little inventions fly off the shelves. But all I have to get through is a few cold nights then we will be on our way to spring.

That way I'll have the whole year to take care of it or think about a new and improved system.

Wouldn't you know it, two months out of warranty.

prariepoodle · 02-10-2006, 08:34 AM

fla native, OH No not a space heater to be found? If we were closer I have a extra one that you could use. Course I brought them from cold country. I hope that you get your furnace fixed with out too much trouble.

richfaa · 02-10-2006, 08:53 AM

Quote:

quote:Originally posted by fla native

I decided to do a little more research on how the furnace operates. I have learned the sequence is the Power Switch, Thermostat, Sail Switch, Relay Switch, Limit Switch and then the Circuit Board.

Took off the air vents inside and looked around. I don't think there is anyway to get to any parts without removing the furnace itself. That's what Keystone service says too. They advise against it if you don't know what you are doing.

The calls to repair people have been the same answer, "you need a new circuit board". What I have learned, doing a little research, is that many good boards are replaced before checking out the sequence of the system for more minor problems. Keystone's guess is it is my Limit Switch because I'm not hearing the furnace try to ignite.

There is not a space heater to be found around here.

When it gets cold in FL those seldom thought about little inventions fly off the shelves. But all I have to get through is a few cold nights then we will be on our way to spring.

That way I'll have the whole year to take care of it or think about a new and improved system.

Wouldn't you know it, two months out of warranty.

Sail switch..Sail switch Could not remember the name of that thing. The one time our furnace in our TT did the samething yours is doing it was a stuck sail switch.I think it is just a mico switch that checks for adequate air flow.It is normally OFF and there must be enough air flow by it to activate it..It is a micro switch with a paddle like device attached to it..should be able to see it..Check it out

Montana_70 · 02-10-2006, 09:45 AM

I looked for the Sail Switch. I found a picture of it doing a google search. But I could not see it anywhere on the furnace 'box'.

If anyone knows "where", like top, side, bottom, front or back, point me in the right direction and I will take the air vents back off and have another look.

jrgwdenner · 02-10-2006, 11:17 AM

Fla native, I can relate to your pain, eeerrrr, cold. When we were in Alaska, stuck at Denali because of our contaminated diesel, we were without a space heater and without a source to buy one. Now we have two. They weren't selling them in Alabama when we left in June so we learned our lesson the hard way. Some very nice fellow RVer loaned us one of his heaters and saved the day.

richfaa · 02-10-2006, 01:42 PM

Have no idea where it might be on the Montana furnace but it has got to be in the path of air flow check around the fan,It is not very big, Note the sail switch is before the limit switch if the sail switch switch does not turn On due to proper air flow.. nothing else can happen...

dchafer · 02-11-2006, 06:55 PM

I think you should contact a Keystone dealer there. You are so close to warranty that they may cover the repair especially seasonal problems. Worth a try. Good luck. Diane

jimc · 02-12-2006, 08:35 AM

I am responding with experience on my 2003 Montana 2955RL, which may be the same for you. The sail switch was a micro-type switch (with a lever that when depressed clicked down on a small switch head). The lever has a paddle on it so as the airflow goes across it, the lever is forced against the switch body, closing the switch. On my 2955RL, it was behind the furnace door on the outside of the RV. Short of being loose, there is little that could go wrong here.
If you open the furnace panel inside the RV, you should be able to find the limit reset switch - it is a small, silver circle about the size of a quarter - on mine it was located behind the furnace front panel on the right side. Press that and it should click and maybe you will be in business.
2004 is kind of late in model years to be experiencing circuit board problems, as Keystone and other vendors went to better boards over the years.

Montana_3118 · 02-12-2006, 06:21 PM

Fla native
Please let me know what you find out think my 04 is starting to act the same as yours. It has started to run but only for a few seconds and the shuts down but when it does start it will run till it hits 75 when it is set on 65.
Your right it is cold in Florida 36 now and going down.

stiles watson · 02-12-2006, 06:52 PM

Birdie,

Is your thermostat OEM or have you replaced it? That kind of temperature variance from the setting sounds like a thermostat problem. I changed out our Domitech for a Honeywell that I bought at WalMart for cheap. It worked with greater efficiency and a smaller temperature variance.

Montana_70 · 02-13-2006, 02:04 AM

jimc,

Thanks for you reply. My furnace is a Suburban SF series. It's located just inside the door on the floor of the island counter, under the hot water tank. I have yet to locate a "furnace door just outside the RV". I have a hot water heater grate I can open and then a small 5X3 two hole vent for the furnace but no door.

When I take the panel off which is located inside the kitchen area, it's a small panel with four screws, I can shine my flashlight and see a lot of red and white wires and silver air hose but no reset switch. The opening is only 5 1/2 by 7 inches so it's not easy to see the front of the furnace.

Montana_3118 · 02-13-2006, 03:20 PM

Update 4 am it was 50 inside no heat turned on the electric heater in the bed room. 6:30 am 42 inside Florida power went down no electric heat it was cold.
Talked with the folks at Suburban we conclude it was the thermostat call Duo-Therm it was still under warranty. Installed a new one this afternoon and now have heat I think it will be needed tonight low around 29.

richfaa · 02-13-2006, 03:51 PM

Exactly what part of Flordia are you in...It is warmer than that in Northern , Ohio

Montana_3118 · 02-14-2006, 01:25 PM

Christmas Fl. Staying at the Airstream Park it only got down to 31 last night
but it stayed warm inside.

sreigle · 02-17-2006, 01:00 PM

BJ, this is a very long shot but since you don't often use the furnace.... do you have mud daubers down there? They love the smell of propane and have been known to go in through the outside ports and build a nest inside. They cause all kinds of havoc in there. This is the reason many of us have mud dauber screens over those outside ports. I would think mud daubers could keep the sail switch from working properly as well as mess up other areas.

If not mud daubers, spiders also like propane and can cause problems.

CountryGuy · 02-17-2006, 02:50 PM

Steve, I don't think those are such long shots, both are miserable pests and can cause havoc with gas furnace, gas water heater, and gas on the frig! BLAH to pests!

BJ, hope ya got it fixed by now!

Montana_70 · 02-18-2006, 01:05 PM

I checked for daubers but did not find any or anything else that was an obvious blockage.

No, it's not fixed. But I made it through. Only had to go through two mornings of waking up to 36 degrees INSIDE!! Made 50 degrees feel like a heat wave. Winter is about over here so I decided to just tough it out and wait until I could turn my attention to the matter without having someone come out and tell me anything and charge me anything to get it going.

I really hate that you cannot get to any of the switches in sequence without pretty much breaking down the furnace unit. But I guess that's a safety feature to keep people like me out of there.

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