gliderguy09 Report post Posted July 8, 2011 Have just purchased a 2004 Monaco Diplomat 3 slide. When the furnace comes on it only works on one side of the motorhome and the other side does not. Checked around the motorhome and realized there are two furnaces. The main one works fine but the one on one living-room slide does not work at all. Any ideas of what could be wrong? Share this post Link to post Share on other sites
shields Report post Posted July 8, 2011 We will need some further details in order to help you out. First, are you positive there are two furnace units? That's a bit unusual in my experience. If there is only one unit, a disconnected warm air conduit at the slide would be a likely culprit. If there are two separate units, let's check a few things. 1. Double check the operating instructions for the control panel. Are you certain that you are properly activating that furnace "zone" and setting the temperature above ambient conditions? Are there two separate control panels? 2. Is there any noise, clicking or other activity when you try to activate that unit? 3. What is the make and model of the inoperative unit? 4. Is there a LPG shutoff valve at the unit, is it properly set? Let us know some additional details and a solution should appear. Good luck, Tim Share this post Link to post Share on other sites
dshepherd Report post Posted July 8, 2011 Shields' advice is right on. I own a 2005 Beaver which has 2 furnaces. I assume you'll have the same thermostat, a digital unit with zone 1 and 2 for furnace, heat pump, and A/C. Make sure your front unit (likely zone 1) is set to furnace, not heat pump, and the temp is turned up. The furnace fan should start after a few seconds. If it does, but no heat, it is likely the igniter or the circuit board on the furnace. If it doesn't turn on, it could be fuse, circuit board, wiring or thermostat. Good luck! Share this post Link to post Share on other sites
wolfe10 Report post Posted July 9, 2011 Excellent advice on this one. As suggested, if you verify that you do have two furnaces and that the controls are set for the second one to come on, please give us details on exactly what happens: 1. Does the fan come on? 2. Do you hear the clicking of the igniter? 3. Does the furnace light, and if so, how long does it run before shutting down? Brett Share this post Link to post Share on other sites
gliderguy09 Report post Posted July 12, 2011 Thanks for all your info. Yes indeed there are two furnaces. One on each side of the coach. The thermostat does not show furnace in Zone 1 but does so in Zone 2. The model is Atwood 8525. Was not aware of the second furnace until realized there was no heat coming from the vents on the kitchen slide. Just went outside to check the model and found a hornets nest inside. Don't know how long they have been there. The furnace does not come on at all , there is no clicking, no nothing. Share this post Link to post Share on other sites
wolfe10 Report post Posted July 12, 2011 After you turn that furnace on with the thermostat, determine if the fan starts running. That is the first step in the process. Gas valve opening and igniter clicking happen after that. If no fan, use a digital voltmeter to check for 12 VDC at the furnace (open outside door to access). Brett Share this post Link to post Share on other sites
tbutler Report post Posted July 12, 2011 The fact that no furnace registers in Zone 1 on the thermostat but does show in Zone 2 suggests that the connection between the furnace and the thermostat may be at fault. If not that it may be a control board problem that prevents the second furnace from registering on the thermostat. A third possibility is that there is no power at all to the second furnace and thus it doesn't register. I would expect the furnace to show up on both Zone 1 and Zone 2 just as our 2 heat pumps and 2 air conditioners do. We have one furnace and it shows on Zone 1, there is no furnace showing on our Zone 2. Share this post Link to post Share on other sites
islandboy1220 Report post Posted November 27, 2015 I have the same problem at this very moment. I have two furnaces, one under the fridge that send one duct forward and handles the bedroom and rear bath. The one under the kitchen sink is not turning on. No power found to the reset switch. I have only found one fuse in the rear bath electric panel for furnace/AC and it is good. Are there more fuses somewhere that I am missing? One clarification - I see both zones for furnace on my thermostat. Share this post Link to post Share on other sites
hermanmullins Report post Posted November 27, 2015 islandboy, Welcome to the Forum. Bud, we need a bit more information. Make, year and model of your coach and what make of heater do you have. With this information folks with the same unit can advise you. Herman Share this post Link to post Share on other sites
wolfe10 Report post Posted November 27, 2015 islandboy1220, Yes, welcome to the FMCA Forum. There should be a separate 12 VDC fuse for each furnace. Share this post Link to post Share on other sites
wildebill308 Report post Posted November 27, 2015 islandboy1220, Welcome to the forum. After you check the fuse in the thermostat go to the zone where the furnace is not showing up and cycle through the "Mode" settings. See what it says about heat. Hear is something simple to try that has fixed several problems with the thermostat before. Take the front off the thermostat take out the fuse, make sure the fuse is good, re-install the fuse and see if it is working properly now. You could re cycle all power in the coach but this is easier. Bill Share this post Link to post Share on other sites
islandboy1220 Report post Posted November 27, 2015 We found it. There is a multi wire plug (actually two plugs) and one was hidden from sight under the sink/counter at the back of the slide and unplugged. Everything is working now. Thanks for the input! Share this post Link to post Share on other sites
