Sail switch power

[Mark28RYR]

Originally Posted by LHaven

Well, this is clearly wrong.

There are only four connectors on the furnace. Find the vacant one that's supposed to have a blue wire on it, and connect these.

On a separate note, keep in mind that there's nothing magic about inCommand when it comes to HVAC. It doesn't "exert control" per se. All it does is provide a GUI window into the functions of the existing HVAC gateway box. All the "features" it provides are actually provided by and in the gateway box, inCommand merely conveys your wishes to it. That's why once your desired HVAC behavior is set, it will continue to function even if inCommand goes offline or loses power.

Maybe so but it’s worked for 3 years this way and it’s even working periodically now without it connected.

[Mark28RYR]

Originally Posted by jsb5717

Maybe ChuckS or Chuckster has an idea, but I haven't seen that symptom before. IMO, either something is wired incorrectly or the control board is whacky.

Just to prove the issue I would leave the sail switch jumped as you've done it and also jump the limit switch to see if you get the same result.

I haven't gone back through the entire thread, but have you checked to see if you have a resettable furnace fuse? If the fuse is black then replace it with a standard blue 15a fuse.

Changed fuse. Jumped the limit switch. The sail switch is normally open according to the schematic so I left it not jumped until after the blower starts, then I jump it. Still no ignition. Must be something with the board then? I’ve tried a second board and I actually have a third inbound for tomorrow so I can try that one. It’s just so strange…

[jsb5717]

It is strange. You don't have to go through that sequence, though. Just jump the switch and leave it jumped. As I said, also jump the limit switch just to be sure. I'm still suspecting the control board, but it's good to be sure.

[Mark28RYR]

Originally Posted by jsb5717

It is strange. You don't have to go through that sequence, though. Just jump the switch and leave it jumped. As I said, also jump the limit switch just to be sure. I'm still suspecting the control board, but it's good to be sure.

When I tried it that way the blower never came on, i could hear some type of whine coming maybe from the control board, and then on subsequent startups with it pulled apart I couldn’t get the blower to start. It finally did. Almost like it timed out when I had the sail switch bypassed before initiating startup that first time.

[Mark28RYR]

Originally Posted by ChuckS

I personally think you need to START OVER with your trouble shooting and use a TS chart and service manual... Otherwise you are just running around in a circle jumping from this to that and will never get anywhere at this rate

https://techsupport.pdxrvwholesale.c...anual-2015.pdf

Thank you. .

[jsb5717]

Originally Posted by Mark28RYR

When I tried it that way the blower never came on, i could hear some type of whine coming maybe from the control board, and then on subsequent startups with it pulled apart I couldn’t get the blower to start. It finally did. Almost like it timed out when I had the sail switch bypassed before initiating startup that first time.

But I would do it again now that you've got a good fuse installed. Just through that black fuse away. If you had the black fuse installed last time you jumped the limit switch then it was a different test.

Good blue fuse, limit and sail switches jumped. What happens?

[LHaven]

Originally Posted by Mark28RYR

Maybe so but it’s worked for 3 years this way and it’s even working periodically now without it connected.

OK, then, don't bother finding the fourth connector and seeing what it's connected to.

[Mark28RYR]

Originally Posted by LHaven

OK, then, don't bother finding the fourth connector and seeing what it's connected to.

How can I have a working furnace sometimes and sometimes not if that wire is supposed to be connected to something? Wouldn’t it just not work at all? There’s no wire anywhere in the vicinity. The rest of them are made into a loop and then go into a hole through the cabinet. All together. I can peer through a opening for the ductwork and follow that group of wires as they travel together. No 4th wire. The furnace ran for 10 hours yesterday on and off on and off with no issue and then just stopped. What’s that wire got to do with that?

[LHaven]

You can locate the fourth connector and find the answer, or you can wave your hands and speculate.

[Lee]

Originally Posted by jsb5717

But I would do it again now that you've got a good fuse installed. Just through that black fuse away. If you had the black fuse installed last time you jumped the limit switch then it was a different test.

Good blue fuse, limit and sail switches jumped. What happens?

Jeff, The furnace fan WILL NOT come on with the Sail Switch shorted when heat is called for. This is normal.

When heat is called for, the Control board first looks for an OPEN sail switch, if open the fan is spun up, then the control board expects to see the Sail switch close.

[jsb5717]

Originally Posted by Lee

Jeff, The furnace fan WILL NOT come on with the Sail Switch shorted when heat is called for. This is normal.

When heat is called for, the Control board first looks for an OPEN sail switch, if open the fan is spun up, then the control board expects to see the Sail switch close.

That's a new concept to me. In the troubleshooting I've done, starting with a closed circuit doesn't cause a failure.

[Mark28RYR]

Originally Posted by Lee

Jeff, The furnace fan WILL NOT come on with the Sail Switch shorted when heat is called for. This is normal.

When heat is called for, the Control board first looks for an OPEN sail switch, if open the fan is spun up, then the control board expects to see the Sail switch close.

Definitely seems to be the case with my furnace. I haven’t had an opportunity to troubleshoot further today but last evening I was able to run the furnace and it warmed the RV up from 41 degrees to 68 degrees. Took a while but it did it. Then about 5 minutes after it stopped it kicked on but didn’t ignite. Didn’t try again after that. This morning same scenario however I think it may of kicked on a couple times and worked before just stopping again. It’s setup where the A/C fan kicks on with the furnace and that will continue to stay running after the furnace quits.

[JRTJH]

Originally Posted by Mark28RYR

Definitely seems to be the case with my furnace. I haven’t had an opportunity to troubleshoot further today but last evening I was able to run the furnace and it warmed the RV up from 41 degrees to 68 degrees. Took a while but it did it. Then about 5 minutes after it stopped it kicked on but didn’t ignite. Didn’t try again after that. This morning same scenario however I think it may of kicked on a couple times and worked before just stopping again. It’s setup where the A/C fan kicks on with the furnace and that will continue to stay running after the furnace quits.

With all the troubleshooting and parts that have been thrown at the furnace, have you considered that your problem "may not be the furnace" ???

You may have a propane issue caused by either contamination in the regulator or in one of the pigtail safety devices or possibly, just a "physics reality" that propane doesn't flow readily (convert from liquid to gas state) as the temperature goes down.

Just a "well used 30 pound propane tank" with too much mercaptan (an oily substance that gives propane its distinct smell) can cause a regulator to not work properly. You might want to take a look at this chart and realize that just the temperature going down can affect the propane output from the regulator enough to cause the furnace gas valve to fail to provide enough propane and cause an intermittent "no ignition problem". Add a "fouled regulator diaphragm caused by mercaptan" and you may have a "perfect storm brewing in the propane system" with no problem with the furnace....

[jsb5717]

Originally Posted by JRTJH

With all the troubleshooting and parts that have been thrown at the furnace, have you considered that your problem "may not be the furnace" ???

You may have a propane issue caused by either contamination in the regulator or in one of the pigtail safety devices or possibly, just a "physics reality" that propane doesn't flow readily (convert from liquid to gas state) as the temperature goes down.

Just a "well used 30 pound propane tank" with too much mercaptan (an oily substance that gives propane its distinct smell) can cause a regulator to not work properly. You might want to take a look at this chart and realize that just the temperature going down can affect the propane output from the regulator enough to cause the furnace gas valve to fail to provide enough propane and cause an intermittent "no ignition problem". Add a "fouled regulator diaphragm caused by mercaptan" and you may have a "perfect storm brewing in the propane system" with no problem with the furnace....

This is a good thought. On my furnace the regulator was the culprit. A good Marshall Excelsior solved that one. On another furnace I fixed turned out to be the furnace gas valve itself. We discovered that it was yielding a reduced flow so sometimes it would run, other times it wouldn't start. A new gas valve solved it.

[Mark28RYR]

Originally Posted by JRTJH

With all the troubleshooting and parts that have been thrown at the furnace, have you considered that your problem "may not be the furnace" ???

You may have a propane issue caused by either contamination in the regulator or in one of the pigtail safety devices or possibly, just a "physics reality" that propane doesn't flow readily (convert from liquid to gas state) as the temperature goes down.

Just a "well used 30 pound propane tank" with too much mercaptan (an oily substance that gives propane its distinct smell) can cause a regulator to not work properly. You might want to take a look at this chart and realize that just the temperature going down can affect the propane output from the regulator enough to cause the furnace gas valve to fail to provide enough propane and cause an intermittent "no ignition problem". Add a "fouled regulator diaphragm caused by mercaptan" and you may have a "perfect storm brewing in the propane system" with no problem with the furnace....

Could that affect the furnace from trying to ignite even if it’s not connected to propane? When I’m troubleshooting it I’ll have it sitting in the floor sometimes disconnected from the propane line and I hear the igniter and all seems well and other times I won’t, just the blower and then quits.

[Lee]

Originally Posted by jsb5717

That's a new concept to me. In the troubleshooting I've done, starting with a closed circuit doesn't cause a failure.

Jeff,

I have read it is designed this way for safeties sake.

Example: If the sail switch failed in the closed state and the blower motor were to fail, the Control board would think all is Ok., then the combustion chamber would fill up with LP and as soon as the ignitor fired = KA-BOOM.

The Control board first looks for an open sail, then it looks for a closed sail after the blower motor comes online, then the LP solenoid opens and the ignitor fires.

[jsb5717]

Originally Posted by Lee

Jeff,

I have read it is designed this way for safeties sake.

Example: If the sail switch failed in the closed state and the blower motor were to fail, the Control board would think all is Ok., then the combustion chamber would fill up with LP and as soon as the ignitor fired = KA-BOOM.

The Control board first looks for an open sail, then it looks for a closed sail after the blower motor comes online, then the LP solenoid opens and the ignitor fires.

Makes sense from a safety perspective. Next time I troubleshoot a furnace I'll test for that as well for future reference.

[JRTJH]

Originally Posted by Mark28RYR

Could that affect the furnace from trying to ignite even if it’s not connected to propane? When I’m troubleshooting it I’ll have it sitting in the floor sometimes disconnected from the propane line and I hear the igniter and all seems well and other times I won’t, just the blower and then quits.

The way I understand the ignition sequence theory, the furnace does not know if there is propane pressure provided to the control valve or not. The sequence proceeds "as if it were ready to function" and then, if there is no propane or a propane problem, the ignitor circuit will attempt to ignite the flame and the flame sensor will either detect ignition or detect ignition failure and the control board will either "lock in normal function" or shut down the control valve and start the purge function.

So, in theory, you should hear the ignition clicks every time you start the furnace heat cycle, whether propane is connected or not. So, if you are saying that sometimes you hear the ignitor and other times you don't hear the ignitor, then I'd say that you have a problem with the furnace "normal function". Troubleshooting should follow the "sequence of operation". If you don't have that in front of you, you can download it here: https://myrvworks.com/wp-content/upl...ing-Manual.pdf

Page 30 is the sequence of operation. If you read through that and understand it enough to follow the sequence with your finger on the actual furnace components, you'll see where each part is and what happens during the sequence. That will give you a much better understanding of what is happening and why it happens that way.

This is just an opinion, but you've changed the sail switch several times without a fix, you've changed the control board twice with a third one on order without a fix. It's not those components. Either it's the control valve, the iginitor/flame sensor or it's the propane supply.

ADDED: You MUST HAVE an open sail switch (0VDC) on the sail switch output to initiate the sequence. Without that "safety confirmation" the control board will assume the sail switch is not functioning properly and will shut down the furnace to prevent a potential hazard condition.

ADDED TO THE ADDITION: Here is a cut and paste of the sequence of operation from the linked manual. You'll see that if the sail switch is not "open at sequence start" (along with other safety checks) then the sequence will not start and the fan will not be powered on.

[LHaven]

Originally Posted by JRTJH

Either it's the control valve, the iginitor/flame sensor or it's the propane supply.

Or -- and y'all know my hobbyhorse -- Mickey done chewed your wiring. [LINK]

Check the thread out. Intermittent furnace operation for two years before it was found and fixed. Maybe the symptoms will ring a bell.

[JRTJH]

Originally Posted by LHaven

Or -- and y'all know my hobbyhorse -- Mickey done chewed your wiring. [LINK]

Check the thread out. Intermittent furnace operation for two years before it was found and fixed. Maybe the symptoms will ring a bell.

Sad part is that the insulation on the wiring used in most "RV grade low bid appliances" is made in China from vegetable based oil products (soy or corn). Sadly, soy and corn based insulation "smells like mouse food" and can become the target of a winter rodent infestation.... So, yep, Mickey is naturally attracted to the insulation on RV furnace wiring.....