Atwood 8531 Furnace Troubleshooting (Sail Switch Location)
It is in an awkward location. The sail switch has limited duty which may be the reason why it is so hard to access. usually, to fix it or work on the switch, you have to remove the furnace to get to it. However, some troubleshooting can be done without that extra work if you are careful.
It is said that the sail switch rarely fails. But that does not mean it doesn’t. You have to check to see if the controller has started the ignition problem or not. If it has, then the sail switch is not the problem. Another part is causing the problem.
To learn more about the sail switch, what it does, and how to repair it, just continue reading our article. It has the information you want to know about so that you can make timely repairs or get a replacement sail switch
Atwood 8531 Furnace 101
Atwood 8531 Furnace Troubleshooting
There are 3 common problems that keep resurfacing in many of these models of Atwood furnaces. The sail switch is not on this list as you shall soon see:
#1. Furnace not working- this is due more to the electrical wiring and system than any other part. It could be the battery, the generator or it could be the wiring. Check the wires for shorts, loose connections or cuts, etc. Replace any that are damaged.
#2. Burner keeps turning off- This happens when you are low on propane or your sensors are dirty. Check your fuel supply and give those sensors a good cleaning. Or it is the burner that has gone bad. Replacing the burner and the sensors is often your only repair option.
#3. Furnace not starting- this is also an electrical issue and you should check your fuse and the breaker to see if there was a power surge or short. Also, check the battery, generator, and connections to make sure those items are not the problem.
Atwood 8531 Furnace Not Igniting
The source for this issue may be that you opened the propane tank valve too quickly. There are times when you do that, the valve will lock up and not let any propane reach the furnace. Close it again and turn the valve back on slowly to see if this solves the problem.
Or you have a control board problem and the right signals are not being sent to the ignition parts. If this is not the source, you should check the vents to see if they are obstructed. If so, clean them out.
Finally, check your DC power. While RV and travel trailers have standard traditional 110 outlets, the appliances are run on DC power. Check to see if you have enough power reaching the furnace. If not, then you need an electrician to help you fix the issue. Sometimes it is best to have a professional look at the problem.
Atwood 8531 IV-DCLP Lights But Won't Stay Lit
The above sources in the previous section will also apply here. You may have a problem with those parts and you should check them first before moving on to other possible sources.
Because the furnace does light up, the sail switch is not going to be your problem. However, your source may be animal and not mechanical. Check your vents, both intake, and exhaust.
Look for any animal nests or beehives that may have been built inside. Even a spider’s web can cause this issue so do not let it remain either. Clean out those obstructions and check your furnace again. If it lights and stays lit, then you have solved the problem.
Finally, you may just have to change your propane tanks., You may not be getting enough fuel pressure to keep the furnace lit.
Where is The Sail Switch on an Atwood 8531 Furnace?
This little part is set deep inside your furnace. It is located between the valve and the ignition control, just above the limit switch. At least that is the location in the manual. The sail switch connects to the limit switch, the thermostat, and the ignition control.
To get to it you usually have to pull the whole furnace out and then open it up so you can see all the parts. This can be a lot of work for one person. The sail switch only closes the circuit to the control board and that is about its only function.
If something is wrong, it is rarely this switch. But to check it, if you suspect it has failed, you can use a long wire with a hook in it to pull or push the sail switch closed.
Atwood 8531-IV-DCLP Gas Valve
Amazon has a lot of Atwood furnace parts for sale on its web pages. There is one gas valve listed among all the other parts and it runs for almost $130. Unfortunately, that is not the same part as the 8531-IV-DCLP model.
Amazon does not list that part on its web pages. You may have to contact Atwood directly or one of its authorized dealers to find that part and get the price for it. There is a part, the 31150 Furnace Hydro Flame Side Outlet Gas Valve, that is said to be compatible with the 8531-IV-DCLP valve and it costs $80 at one outlet.
It is supposed to be compatible with several gas valves Atwood makes. Those gas valves are 8516-IV, 8520-IV, 8525-IV, 8531-IV, and 8535-IV. It will also be compatible with other gas valves, 8516-III, 8520-III, 8525-III, 8531-III, and 8535-III, as long as their serial numbers are after 0654747.
Atwood 8531-IV-DCLP Parts Diagram
Generally, the owner’s manual will have a parts diagram on one of its pages. We will be linking to those manuals at different websites in the last section of this article. But this link will take you to a website that isolates the parts diagram so you can see where all the parts are at a glance.
The diagram has numbers labeling each part, but unfortunately, there is no legend on that web page listing what parts those numbers identify. We scrolled down and found a second parts diagram but again, no legend.
The sail switch is listed by name and you can see how difficult it is to get to by this diagram. It is in the middle of all the parts.
8531 IV DCLP Wiring Diagram
Fortunately, the wiring diagram is at the same link as above. You just have to scroll down a little way to see it. The diagram is past the photo of the wiring system. If you understand electronics, this diagram should be easy to read. It is well marked with abbreviations letting you know which wire is which color.
However, you can also get a wiring diagram in the manual. It is near the front of the book and it too is well labeled. The key, of course, is to know your electronics and how to read a wiring diagram. If you do not know how to read one, call in a pro to help you
Atwood 8531 Airflow Limit Fault
There is a built-in error code letting you know where the problem lies. If it blinks once every 3 seconds, the error code is telling you that it is the limit switch. Now, even though the error code directs you to that switch, the problem could be another part and the limit and sail switches are doing their jobs correctly.
There is a possibility that the sail switch failed but to check it, you have to use a multimeter to see if there is any power coming from the limit switch to the sail switch. If there isn’t, then the limit switch is bad, and if there is, you have to check the sail switch to see if any power is getting to the control board.
If not, then the sail switch may have failed. both parts will have to be replaced if either failed.
Download Atwood 8531 Furnace Manual
We have a couple of sources for owner’s manuals. This first link has a variety of owner’s manuals for different 8531-IV Atwood furnaces. You just have to click on the link that takes you to the one you need. Just click here to get to that website.
The next website will take you to our go-to download manual website. Click here to get to the manual. Both sources should be easy to read and navigate.
Some Final Words
In most cases, the sail switch should not be the problem. It can be but rarely does it fail. When it does, you may have to remove the furnace to gain access to it or replace it. There are other sources for the problems you may be experiencing, even if you see a limit switch error code.
If you are not great with electronics, or you are still under warranty, let the pros handle the problems.
