Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > iRV2.com COMMUNITY FORUMS > iRV2.com General Discussion
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 10-13-2016, 09:36 PM   #1
Member
 
Join Date: Sep 2016
Location: Monticello, MN
Posts: 91
Atwood Furnace not lighting, AC is Clicking.

Hey Guys,
I have a Atwood 8940 Furnace and a 4 button duo-therm Thermostat. When I switch the thermostat to Furnace, nothing happens at the furnace, but I do get a consistent click, like a relay is turning on and off in the front Roof mounted AC. Any ideas? Thanks!

2000 Monaco Diplomat 38A
Jfreeman is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 10-13-2016, 10:20 PM   #2
Senior Member
 
BFlinn181's Avatar
 
Gulf Streamers Club
Join Date: Jan 2012
Location: Cincinnati
Posts: 19,925


Is your A/C unit a heat pump? Perhaps the heat setting is calling for the heat pump to come on. This is the manual for your thermostat.
__________________

Bob & Donna
'98 Gulf Stream Sun Voyager DP being pushed by a '00 Beetle TDI
BFlinn181 is offline   Reply With Quote
Old 10-14-2016, 07:53 AM   #3
Member
 
Join Date: Sep 2016
Location: Monticello, MN
Posts: 91
Quote:
Originally Posted by BFlinn181 View Post


Is your A/C unit a heat pump? Perhaps the heat setting is calling for the heat pump to come on. This is the manual for your thermostat.

Thanks for the Manual, I do not have heat strips that I know of anyways. The Control board is a 3106481.009
Jfreeman is offline   Reply With Quote
Old 10-14-2016, 08:44 AM   #4
Senior Member
 
BFlinn181's Avatar
 
Gulf Streamers Club
Join Date: Jan 2012
Location: Cincinnati
Posts: 19,925
If you look at the various wiring diagrams for different set ups, in all cases the thermostat sends the "furnace on" signal through the A/C. That could be the clicking sound you're hearing, a relay in the rooftop A/C control board. Next step is to check for 12v at the furnace control board. If no 12v, then look for a fuse or bad relay in the A/C. You could also use jumper wires to apply 12v directly to the furnace to check that the furnace is capable of working when it gets 12v.
__________________

Bob & Donna
'98 Gulf Stream Sun Voyager DP being pushed by a '00 Beetle TDI
BFlinn181 is offline   Reply With Quote
Old 10-24-2016, 03:33 PM   #5
Member
 
Join Date: Sep 2016
Location: Monticello, MN
Posts: 91
Voltage Test

Hey guys,
This is what I found. This is the board into the AC, and I have no power at the furnace. Anyone have any ideas? What relay controls the Furnace and can you replace just a relay or do you have to replace the whole board. Just a heads up, the 2 AC's work great, the furnace does not work and I head a clicking from the front AC board which is what I have the photo of below. I have the voltage that I get from what I believe is the Furnace output. Does anyone know where P6 goes within the board? Thanks for any help you may be able offer!

Cheers


Jfreeman is offline   Reply With Quote
Old 10-24-2016, 07:20 PM   #6
Moderator Emeritus
 
Gary RVRoamer's Avatar


 
Join Date: Jan 2000
Location: West Palm Beach, FL. USA
Posts: 27,519
The AC zone control board just passes on the thermostat signal, though that two is +12v. The actual power for the furnace goes direct to it from it's own circuit & fuse. You may be getting the thermostat "heat needed" signal at the furnace, but the furnace itself lacks power to run. Check the fuse and wire for that.

Basically, the furnace sits there listening for the thermostat signal, which is +12v on the signal line. The furnace board has its own separate 12v source, which powers the board and the fan.
__________________
Gary Brinck
Former owner of 2004 American Tradition and several other RVs
Home is West Palm Beach, FL
Gary RVRoamer is offline   Reply With Quote
Old 10-25-2016, 11:26 AM   #7
Member
 
Join Date: Sep 2016
Location: Monticello, MN
Posts: 91
Quote:
Originally Posted by Gary RVRoamer View Post
The AC zone control board just passes on the thermostat signal, though that two is +12v. The actual power for the furnace goes direct to it from it's own circuit & fuse. You may be getting the thermostat "heat needed" signal at the furnace, but the furnace itself lacks power to run. Check the fuse and wire for that.

Basically, the furnace sits there listening for the thermostat signal, which is +12v on the signal line. The furnace board has its own separate 12v source, which powers the board and the fan.
Thanks Gary, it must be passing the 12 volts through a relay that is clicking? I am not getting any voltage at the furnace board connector and only 1-2 volt jumps every time it clicks on the furnace wires marked blue in the diagram below.
Jfreeman is offline   Reply With Quote
Old 10-25-2016, 05:21 PM   #8
Moderator Emeritus
 
Gary RVRoamer's Avatar


 
Join Date: Jan 2000
Location: West Palm Beach, FL. USA
Posts: 27,519
Just to be clear, there are two +12 inputs to the furnace board, so I'm not sure which one you are saying has no 12v. The funance power line should be aconstant 12v, and the thermostat wire should have a steady 12v once the relay closes.

If the a/c controller clicks once, odds are that is the relay closing and there should be +12v on the thermostat-->furnace wire. You can jumper +12v from another source to that wire to see if the furnace fan starts up.
__________________
Gary Brinck
Former owner of 2004 American Tradition and several other RVs
Home is West Palm Beach, FL
Gary RVRoamer is offline   Reply With Quote
Old 10-25-2016, 08:39 PM   #9
Member
 
Join Date: Aug 2011
Posts: 42
Not to hi-jack, but I have the exact same issue except I have a model 8535 IV
With a 6 wire tstat. AC and hi/ low fan works on tstat, just won't send 12v to furnace. I have posted in Class A m/h section. This is what I've found after a few days of checks. I can jump the two therm wires at the furnace and have it work as well as jumping the two " blue- white" wires coming out of a/c controller. I checked the 3 amp fuse, all ok. I went inside the a/c controller and found the two blue-white wires on the circuit board. One always has 12v (to furnace) and the other should put out 12v once your tstat asks for it ( moving temp lever up). The one wire will not put out 12v when asked, so I'm planning on buying a new a/c controller circuit board $60 and try it. I can't believe it's the tstat when it works the a/c fine and I have a 2nd tstat in bedroom that gives the same result.
I'll be following your thread to see if you come up with something else. Good luck.
jtjj1958 is offline   Reply With Quote
Old 10-26-2016, 08:59 AM   #10
Member
 
Join Date: Sep 2016
Location: Monticello, MN
Posts: 91
Quote:
Originally Posted by Gary RVRoamer View Post
Just to be clear, there are two +12 inputs to the furnace board, so I'm not sure which one you are saying has no 12v. The funance power line should be aconstant 12v, and the thermostat wire should have a steady 12v once the relay closes.

If the a/c controller clicks once, odds are that is the relay closing and there should be +12v on the thermostat-->furnace wire. You can jumper +12v from another source to that wire to see if the furnace fan starts up.
The relay continually clicks, and the voltage jumps to 1-2 volts on the blue furnace wires. If it is a bad relay, are you able to change out the relay or is it time for a new board? Thanks.
Jfreeman is offline   Reply With Quote
Old 03-14-2017, 05:15 PM   #11
Member
 
Join Date: Sep 2016
Location: Monticello, MN
Posts: 91
Hey jtjj1958,
Did you have any luck changing out the board? Was that it?
Jfreeman is offline   Reply With Quote
Old 03-16-2017, 10:47 PM   #12
Senior Member
 
simplecamper's Avatar
 
Carolina Campers
Join Date: Aug 2016
Posts: 112
I was a NATE certified HVAC but not on RV but that what it looks from the board is that it is the relay as you and others suspect. P6 just prevent over load to the shedding leads, but shedding to what that I have no idea other wise it just directs the 12 volt to furnace. My concern is I would expect single clicks not reoccurring clicks unless the relay cannot hold the control power constant so it is like the call for heat is going on and off. Now to test this you would have to disconnect the thermostat and phyically connect the wires that make the call for heat. Test voltage then at the relay and see if it holds, if it does no fluctuate and the relay still clicks bad relay. it the control voltage fluctuates to the relay them thermostat is bad. I would like to see more of the wiring besides the board, really guessing at some of this. Thermostat wiring is all pretty much common.
__________________
Loving the outdoors!
simplecamper is offline   Reply With Quote
Old 03-18-2017, 10:37 AM   #13
Member
 
Join Date: Aug 2011
Posts: 42
Quote:
Originally Posted by Jfreeman View Post
Hey jtjj1958,
Did you have any luck changing out the board? Was that it?
Yes it was. I put in a new digital tstat with a new controller that connects to your AC unit (operates both heat and AC) and that solved it. Could have bought just the replacement board for $60 or so but for $100 got a new digital tstat and new control unit, better upgrade.
jtjj1958 is offline   Reply With Quote
Reply

Tags
ace, atwood, furnace, light



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Clicking sound from furnace area wolfcreek Palazzo Motorhomes 4 06-16-2016 06:33 PM
Atwood water heater clicking noise csj2 RV Systems & Appliances 6 04-10-2013 07:16 PM
furnace self starter constantly clicking captaindesmo RV Systems & Appliances 2 11-09-2011 07:51 PM
Furnace not lighting Dan DeBruin RV Systems & Appliances 3 03-26-2011 09:30 PM
Furnace Not Lighting @ 65 MPH max49 MH-General Discussions & Problems 5 01-15-2007 05:50 AM

» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 08:54 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.