Supurcar Posted February 6, 2008 Share Posted February 6, 2008 I have a question on the Sunrader furnace. I have a 1987 Sunrader and it has a furnace that will auto light. It worked fine for our trips to California and worked fine on a few local trips last month. Just over a week ago it got real cold, in the teens and it snowed over a foot. I am not sure if that has anything to do with it or not, but just the conditions of the failure I guess. So to continue the furnace lit and worked fine one day and then would not light the next. We noticed it was just blowing cold air for over an hour and realized something must be wrong. A couple of times in the past when the coach battery was low it (the furnace) would not light, but we just figured it was low battery (we have a guage to tell how much juice the battery has, LP in the tank, black and grey water etc.), when we finally plugged it in to a land line it would work fine on those occasions. So here I am a week since it has worked, still not able to light the thing, I turn on the gas valve, turn on the furnace and the fan growls a bit (bearings are another story) like usual and then comes on and blows cold air. There is a noticable "clunk" a moment after turning on the furnace switch followed by a softer "clank" a few seconds later. sounds almost like a switch or relay. I wanted to see if anyone had a similar issue or had any quick fixes. FYI- the gas has is still reaching the stove and I can light that still. Quote Link to comment Share on other sites More sharing options...
Supurcar Posted February 7, 2008 Author Share Posted February 7, 2008 And I just finished opening the outside cover and taking a look. It is very cold so I did not spend a lot of time on it. I did notice right off that there was 4 golf ball size hornets nests in there. The first sound I heard must have been a valve opening, since I smelled gas after it happened, the second sound was of an ignitor clicking, and the third must have been the valve closing when it did not light. I bet it is simply some debris in there somewhere. It is a hydra flame or something like that. I think I will wait until it warms up some before I attempt to dismantle the thing. Quote Link to comment Share on other sites More sharing options...
Diesel_Aggie Posted February 7, 2008 Share Posted February 7, 2008 It's very common to get debris in the RV furnaces that block sufficient gas flow to light off. Odd that it would suddenly occur in the winter but but based on the hornets nest I'd certainly suggest a good cleaning when weather permits. If you will do some searching on RV furnaces you can find some decent trouble shooting tips. If I remember correctly there are 3 things that can cause it to go into lockout mode, one of which is low gas pressure. Here is the Suburban Furnace FAQ link: http://www.rvcomfort.com/suburban/service/...s_questions.php http://www.rverscorner.com/furnace1.html is a good place to get started. There's a lot more out there, I just don't remember where I found stuff since it's been a couple of years. I'd highly recommend the fine mesh screens that go over the outer area of the furnace to prevent problems in the future. Quote Link to comment Share on other sites More sharing options...
futar Posted February 8, 2008 Share Posted February 8, 2008 This is probably unrelated but it's something that you should know. A woman friends Sunrader heater did not work. I checked the schematic and found that there's a sequence of operation before it can ignite. The first entails a solenoid that turns on the motor. Like all solenoids, the points inside can wear. It is round about and inch in diameter with two wires in and two out. I checked it with a voltmeter and it had failed. I replaced it and every thing worked just fine. Quote Link to comment Share on other sites More sharing options...
Supurcar Posted February 9, 2008 Author Share Posted February 9, 2008 Thanks for the tips, I was wondering on the reply from Futar what the furnace was doing or not doing. You mention it did not work, was it simply the blower not running or was the blower running and no heat coming out? I think the link he (deisel) left on the first reply might be the answer that mine went into a lockout mode for some reason. I hear it trying to run thru the cycle and then it kinda kicks out, so maybe it has a bad part. I have not had time to play with it, but I may take it to a shop if it is not something obvious. I was also told in real cold weather the LP will create an thick oil that can restrict the line somehow. But I do smell the gas when it goes thru the start up cycle, but there is no ignition. Quote Link to comment Share on other sites More sharing options...
Gulfstream Greg Posted February 13, 2008 Share Posted February 13, 2008 Thanks for the tips, I was wondering on the reply from Futar what the furnace was doing or not doing. You mention it did not work, was it simply the blower not running or was the blower running and no heat coming out?I think the link he (deisel) left on the first reply might be the answer that mine went into a lockout mode for some reason. I hear it trying to run thru the cycle and then it kinda kicks out, so maybe it has a bad part. I have not had time to play with it, but I may take it to a shop if it is not something obvious. I was also told in real cold weather the LP will create an thick oil that can restrict the line somehow. But I do smell the gas when it goes thru the start up cycle, but there is no ignition. When the blower motor starts there are two fans. One that circulates the air inside the coach and another that circulates combustion air through the combustion chamber. What Futar is talking about is whats called the sail switch that is activated when the blower operates. The sail switch competes the gas valve circuit through the ignition module that allows the gas valve to open. I think you are correct though that you need a thorough cleaning. Here is a link to the hydro flame manuals in the gallery. http://toyotamotorhome.org/forums/uploads/...0_57_842826.pdf Quote Link to comment Share on other sites More sharing options...
bufbooth Posted February 15, 2008 Share Posted February 15, 2008 I think the core problem is power related, mainly because the problem goes away when the RV is finally plugged into a land line, but the power problem is coming from the fan. You may want to service the furnace fan, if it is "growling", it is either not turning at the designed speed, or it is putting a draw on the power going to the furnace. Either problem can cause the furnace to fail, if the fan is not turning at the proper speed, it could be causing issues with the circulating of the combustion air through the combustion chamber. If the growling fan is using too much power, it could be causing the glow plug/ignitor from not being able to get hot enough to ignite the gas. The fact that the furnace will work when you plug it into a land line tells me that you are now getting power that will not dip, that is there is plenty of power in reserve to supply a consist source of power. Since the fan needs servicing to take care of the growling, I would not do anything to the furnace until the fan is fixed, you may not have to do anything else. Dennis... Quote Link to comment Share on other sites More sharing options...
bufbooth Posted February 15, 2008 Share Posted February 15, 2008 How do I get a picture to display under my name? TKS, Dennis... Quote Link to comment Share on other sites More sharing options...
DanAatTheCape Posted February 16, 2008 Share Posted February 16, 2008 I have a question on the Sunrader furnace. I have a 1987 Sunrader and it has a furnace that will auto light. It worked fine for our trips to California and worked fine on a few local trips last month. I understand that propane is (or used to be) mixed with butane for use in warm climates. (from my 1991 owners manual) and if one bought LP gas in a warm climate, drove to a cold climate, that the gas appliance may nto work. Does this apply to your situation? I do not know. Quote Link to comment Share on other sites More sharing options...
Gulfstream Greg Posted February 19, 2008 Share Posted February 19, 2008 How do I get a picture to display under my name?TKS, Dennis... Look above for the link "My Controls". Once there over on the left is "Edit Avatar Settings". You will be able to upload a photo there. Quote Link to comment Share on other sites More sharing options...
bufbooth Posted February 19, 2008 Share Posted February 19, 2008 Thanks for the help on the picture. Quote Link to comment Share on other sites More sharing options...
Maineah Posted February 20, 2008 Share Posted February 20, 2008 I agree with the lack of power. If the fan is using too much power it will drop the voltage even if the battery is at rated voltage. Plugging the camper in will raze the voltage a couple of volts and over come a weak fan. The fan has to run at full speed to trip the sail switch. With out full air flow the sail switch will not allow the gas valve to open. If it is an original igniter board you only get one chance to get the fire lit so every thing has to be just right. One thing that all ways bothered me is why didn’t they have a timer to shut the fan off after awhile if the heater didn’t light? That blowing cold air thing sucks! Quote Link to comment Share on other sites More sharing options...
Supurcar Posted April 29, 2008 Author Share Posted April 29, 2008 Here is the latest on the furnace, we went for a test run overnight to a local RV park. I plugged into the land line and turned on the gas. The water heater fired right up and the stove was working fine. I noticed after some time a funny sound coming from the converter box or panel. I had the fridge on elec mode at the time. The sound from the panel was kind of a chirp like a relay trying to trip and then not engaging. It did this in a cycle for hours until I realized what was going on. I tripped the breakers trying to isolate what was causing this. finally I wanted to try my fridge on gas for the first anyway, it fired up like a champ and seemed to be working fine, and lo and behold the chirping sound went away from the converter box. I think I have an electrical issue with the fridge now. This is even funnier, after I got the fridge to work on gas, I thought maybe this is related to the furnace not working so I fired up the furnace as it was almost cold enough to need it anyway. Again behold the furnace fired right up for the first time in months, and I ran it for about 30 minutes, I was in heaven for a while. After I turned off the furnace I can not get it to light again, DOH! This can not be a major repair, I just have not had time to tear it down as I have been working on the carpets. Any tips? Quote Link to comment Share on other sites More sharing options...
Maineah Posted April 30, 2008 Share Posted April 30, 2008 That’s a tough call it can get expensive throwing money at a problem until it's fixed it’s probably time to get some one local to have a look at it for you. I had the same problem with mine when I bought it, part of the problem was related to shoddy work by some one and part due to the igniter board. Some times it worked fine and usually when I needed it most it didn’t. A replacement board (dinosaur boards are good ones) usually try 3 times to fire the heater before giving up as opposed to once for the original that’s a plus. Gaskets, dirt, sail, switch, weak fan, gas valves so many things have an effect. The bottom line is that fail safe stuff is there to keep you from launching your motor home over into the neighbor’s yard and they all have to be just right. Quote Link to comment Share on other sites More sharing options...
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