Barry W Posted October 4, 2020 Share Posted October 4, 2020 Have two furnaces, the one under the frig works good and is controlled by zone two or bedroom side of thermostat. The other furnace under kitchen cabinet does not appear on zone one of thermostat, so unable to turn on. Any help? Barry Link to comment Share on other sites More sharing options...
Steven P Posted October 5, 2020 Share Posted October 5, 2020 @Barry W I had that issue last year, but the other way around. My under fridge furnace didn't work. If I remember right, there is a fuse or 2 to check. The issue mine was having was the sail switch was stuck and needed a little bending to free it up. Once that was done, mine would light up and burn. Before doing this, you may want to try to reset your thermostat. Link to comment Share on other sites More sharing options...
Barry W Posted October 5, 2020 Author Share Posted October 5, 2020 I think I have seen how to reset the thermostat, but have forgotten how and where to find instructions. Link to comment Share on other sites More sharing options...
Chuck B 2004 Windsor Posted October 5, 2020 Share Posted October 5, 2020 On my coach, the furnace requires a contact closure to turn it on. There are 2 blue wires coming from the furnace going to the air conditioner circuit board on the roof. Cut those wires, strip them and hold them together to see if the furnace starts. If it does, purchase a generic thermostat at Lowes such as a Honeywell Home RTH111B non-programmable Thermostat. Mount is where you can extend the 2 wires connecting it to the thermostat. You can use that Thermostat to run the furnace. Chuck B Link to comment Share on other sites More sharing options...
Barry W Posted October 5, 2020 Author Share Posted October 5, 2020 What is the two blue wires attached to at the ac? I would prefer to determine why it is not being displayed on current thermostat. Link to comment Share on other sites More sharing options...
Chuck B 2004 Windsor Posted October 5, 2020 Share Posted October 5, 2020 The circuit board in the air conditioner. I was just trying to give you an easy fix without going on the roof. Excuse me!!! Chuck B Link to comment Share on other sites More sharing options...
Barry W Posted October 5, 2020 Author Share Posted October 5, 2020 Thanks for the info, sorry if sounded ungrateful just a OEM kinda of guy, if possible Link to comment Share on other sites More sharing options...
Chuck B 2004 Windsor Posted October 6, 2020 Share Posted October 6, 2020 I posted where the 2 blue wires were attached to on my coach two post I made previous. Chuck B Link to comment Share on other sites More sharing options...
Steven P Posted October 6, 2020 Share Posted October 6, 2020 @Barry W I misread your first post about not seeing the furnace on the Tstat. Can you post pics of what you see? On mine, you can use either heat pump or furnace, so maybe if one of yours is set to HP, you will not see furnace? My tstat has an on off slide switch on bottom to turn fully off. I forget the reset process. Found on FB Try resetting your thermostat. SYSTEM RESET OF DUO-THERM COMFORT CONTROL: a. Turn the ON/OFF switch to OFF position. b. Simultaneously depress and hold the MODE and ZONE push-buttons while turning the ON/OFF switch to ON. FF should appear in the LCD display until the MODE and ZONE push-buttons are released. Link to comment Share on other sites More sharing options...
Barry W Posted October 6, 2020 Author Share Posted October 6, 2020 I googled the reset procedure yesterday and reset the thermostat twice, still have the same problem. Am thinking will go on roof and check if wireing is still intact. When on zone 2 (bedroom) when switching between modes, cool, HP, furnace and fan appear. On zone 1 (living room) just cool, HP, and fan appear furnace does not appear in display. Hope this explains without pics, but if neccessary will include pics in the future posts Link to comment Share on other sites More sharing options...
Chuck B 2004 Windsor Posted October 6, 2020 Share Posted October 6, 2020 The air/HP on the roof is a generic unit capable of fitting several applications. The wiring to it, the switch settings on the circuit board, and the type thermostat used determines how a given application works. Then there is the flat ribbon cable that ties all the units together. If they cannot digitally talk to each other, they will not work the way they are designed to work. You need to make a decision as to what you want to do. If you want to stay OEM from the factory, good luck. If you want the system to work properly, you need to make some changes. Many of the components are no longer available. The new air/HP units come with new designed circuit boards that Are NOT compatible with what you have now. Any failure with what you have now requires a very costly complete change out of all associated components. Then there is the flat ribbon cables that ties the units together so they can communicate with each other. We full timed in our coach for 6 years. In order to keep the DW happy, I had to keep all the systems working the way she was use to being working. There are not many coach owners left that has the HP/furnace found on our coaches. Most had the Aqua Hot system. I suggest that you get out the manuals for your air/HP units and familiarize yourself with each of the components, how they are wired, the many option settings, to better understand what you are dealing with. Chuck B Link to comment Share on other sites More sharing options...
Guest Ray Davis Posted October 6, 2020 Share Posted October 6, 2020 Barry , is this a recent condition or has it shown up on the thermostat before ? Do you still have the original A/Cs ? If they have been up dated you may need to change a dip switch setting . Good luck Link to comment Share on other sites More sharing options...
Barry W Posted October 6, 2020 Author Share Posted October 6, 2020 1 hour ago, Ray Davis said: Barry , is this a recent condition or has it shown up on the thermostat before ? Do you still have the original A/Cs ? If they have been up dated you may need to change a dip switch setting . Good luck This is first time I have checked this furnace to try to use since owning coach for three years. First trip in cold weather. The rear AC was replaced fifteen months ago, front AC is original as far as I know. Where would I find info on t he dip switch settings? Will do more research Link to comment Share on other sites More sharing options...
Guest Ray Davis Posted October 6, 2020 Share Posted October 6, 2020 (edited) So , zone 1 is the front and A/C that's where I would check the dip switches On the roof remove the A/C cover then on the pass side is the control board , it is accessed by removing a metal cover . The dip switches are on that board . They are small and delicate so go easy with them . On mine I have a furnace sw 3rd from the bottom . If your furnace dip sw is off turn it on and do a reset of the thermostat so it will recognize the new setting hopefully that will cure the problem . Take a picture of the original settings so you can return to those settings if necessary . BTW there is 120 v up there so be careful . Edited October 6, 2020 by Ray Davis Link to comment Share on other sites More sharing options...
Bob Nodine Posted October 7, 2020 Share Posted October 7, 2020 12 hours ago, Barry W said: This is first time I have checked this furnace to try to use since owning coach for three years. First trip in cold weather. The rear AC was replaced fifteen months ago, front AC is original as far as I know. Where would I find info on t he dip switch settings? Will do more research Is the new unit installed in the rear one that requires the new thermostat or did the installer exchange the circuit board for an older circuit board compatible with the old thermostat? Link to comment Share on other sites More sharing options...
Barry W Posted October 7, 2020 Author Share Posted October 7, 2020 4 hours ago, Bob Nodine said: Is the new unit installed in the rear one that requires the new thermostat or did the installer exchange the circuit board for an older circuit board compatible with the old thermostat? Exchanged circuit board, the zone 2 where the new unit is installed shows the furnace under the fridge. Zone 1 where old unit is does not show furnace that is under the kitchen cabinet. Have not check the dip switchs on old unit yet will get to that tomorrow. Link to comment Share on other sites More sharing options...
hitechpete Posted October 7, 2020 Share Posted October 7, 2020 23 hours ago, Barry W said: This is first time I have checked this furnace to try to use since owning coach for three years. First trip in cold weather. The rear AC was replaced fifteen months ago, front AC is original as far as I know. Where would I find info on t he dip switch settings? Will do more research see the excerpt from the dometic manual below. Link to comment Share on other sites More sharing options...
Chuck B 2004 Windsor Posted October 7, 2020 Share Posted October 7, 2020 I do not "spoon feed" people. I point them in the direction I feel they need to go and let them determine what to do. Chuck B Link to comment Share on other sites More sharing options...
eddie4ne Posted October 8, 2020 Share Posted October 8, 2020 Just a word of caution. We exchanged our AC units and neglected to set the dipswitch for the furnace. When using the furnace in a condition that would require the it to kick on, since we had not flipped the furnace switch, we ended up blowing the freon line and had to replace the unit again! 1 Link to comment Share on other sites More sharing options...
Barry W Posted October 8, 2020 Author Share Posted October 8, 2020 (edited) On 10/6/2020 at 2:29 PM, Ray Davis said: So , zone 1 is the front and A/C that's where I would check the dip switches On the roof remove the A/C cover then on the pass side is the control board , it is accessed by removing a metal cover . The dip switches are on that board . They are small and delicate so go easy with them . On mine I have a furnace sw 3rd from the bottom . If your furnace dip sw is off turn it on and do a reset of the thermostat so it will recognize the new setting hopefully that will cure the problem . Take a picture of the original settings so you can return to those settings if necessary . BTW there is 120 v up there so be careful . Climbed on roof removed cover on front AC and what I thought was the opening on pass side to control board. Found capacitors but no control board with dip switches. All that was in the opening was part nos. 36,43,& 44 This is the model of Duo-Therm 630035.331 Edited October 8, 2020 by Barry W Link to comment Share on other sites More sharing options...
Guest Ray Davis Posted October 8, 2020 Share Posted October 8, 2020 Barry , Your model is a little different , my board is on top under cover # 38 . Anyway you do have a control somewhere . I saw in your manual it looks like you have a control box accessed from inside . https://www.manualslib.com/manual/799601/Dometic-57908-321.html?page=15#manual Good luck Link to comment Share on other sites More sharing options...
vanwill52 Posted October 8, 2020 Share Posted October 8, 2020 On 10/7/2020 at 2:56 PM, Chuck B said: I do not "spoon feed" people. I point them in the direction I feel they need to go and let them determine what to do. Chuck B Luckily, you are one of a tiny minority on this forum that feel that way. Most everyone else seems happy to bend over backwards to help their fellow RV owner. Link to comment Share on other sites More sharing options...
Barry W Posted October 8, 2020 Author Share Posted October 8, 2020 1 hour ago, Ray Davis said: Barry , Your model is a little different , my board is on top under cover # 38 . Anyway you do have a control somewhere . I saw in your manual it looks like you have a control box accessed from inside . https://www.manualslib.com/manual/799601/Dometic-57908-321.html?page=15#manual Good luck Was able to find dip switches from this post, filp furnace on reset thermostat now both furnaces appear in thermo and both work. Do not know why switch was not right but it is now. Thanks to everyone that posted help Link to comment Share on other sites More sharing options...
Steven P Posted October 9, 2020 Share Posted October 9, 2020 @Barry W That's great news! Congrats on a nice victory. Link to comment Share on other sites More sharing options...
Guest Ray Davis Posted October 9, 2020 Share Posted October 9, 2020 15 hours ago, Barry W said: Was able to find dip switches from this post, filp furnace on reset thermostat now both furnaces appear in thermo and both work. Do not know why switch was not right but it is now. Thanks to everyone that posted help Yeah great news . Air cond is nice but heat is essential especially when DW is cold . It sure feel nice when we find a fix , it even feels nice when we can help . That dip sw was probably like when it left Monaco and no one bothered to figure it out . This forum is the best , great members here . Almost no bickering Link to comment Share on other sites More sharing options...
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