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canman47

Suburban DD17DSI sail switch problem

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Since I've had it the furnace will not ignite on its' own. If I use a stick to pull on the sail switch it lights right up but I had to hold the sail to keep it on. I replaced motor, fan and sail switch and still doesn't work. If I pull the sail it will come on and stay on but when it cycles off it won't reignite on its' own. I have to say that it looks like UPS drove over the sail switch. There were tire marks on the package but they missed the actual switch. The arm however was totally flat and it needs to have a bend in order to put it in the air stream to work. I took a guess as to what kind of bend it needs but I guess I failed. Looks like the actual sail had a bend in it but I'm not sure. Has anyone else messed with these?

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I  unsoldiered the sail and cut a larger one and soldiered it on. The increased area was all it took. On the arm it is supposed to be straight.

Edited by WME

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Hmm, the arm is straight? Mine seems to bump into the tunnel when it's straight and won't activate the switch. I guess the angle where it comes off the switch is messed up. It's more than 90 degrees. What metal did you use for a sail? Guess I'm taking it apart again. At least now I know how to do it.

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OK this is weird. I looked up your furnace and was going to post a pic of the correct switch. Different dealers are showing different switches. One straight arm and  one that is bent:ranting2:

Here is the straight one http://www.dyersonline.com/suburban-furnace-sail-switch.html?utm_medium=shoppingengine&utm_source=googlebase&gclid=EAIaIQobChMI2-P4hIn22AIVgZR-Ch21EgXpEAQYAiABEgKgs_D_Bw

Here is the bent one..https://www.rvplus.com/suburban-parts-sail-switch-assembly-f-dd-17dsi-231930.html?gclid=EAIaIQobChMI2-P4hIn22AIVgZR-Ch21EgXpEAQYBCABEgL38fD_BwE

I went to my local ACE and got a piece of hobby tin and just cut it to the shape I wanted and soldiered it on. Don't make it to big as the weight will effect the switch working

Edited by WME

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3 hours ago, WME said:

I went to my local ACE and got a piece of hobby tin ...

I'm cheap. I'd cut up a Coke can and 'recycle/repurpose' it! :)

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Mine is the bent one. Weird that both suppliers list the same part# but the parts are different. Mine that came out was bent. Can aluminum from a soda can be soldered?

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Can't solider aluminum. maybe a bean can. K&S makes tin and brass sheets should be at your local ACE

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Just remembered something. On a different heater I soldiered a 1" long piece of piano wire and gobbed a blob of soldier on it to act as a counter weight and let the switch function with less breeze.

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Just in case anyone else has this problem, I found a really easy solution if the sail switch isn't catching enough airflow. I had some metal repair tape from an auto parts store that is basically foil with adhesive on one side. I cut a square slightly bigger than the sail and reached down the tunnel and stuck it on the sail. Works perfectly with no disassembly required!

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You might want  to do some real continuity tests there are two things that affect the operation, the sail switch and the over temp switch. Do the test with the thermostat on it does not matter if it's not making heat if the switches are closed the board is toes up. The fan runs in pre purge as soon as the thermostat calls for heat the board starts a timer while the fan is in pre purge it needs to see both the sail switch and the over temp closed before the gas valve will open. So while the fan is running check the leads on the board that attach to the sail and over temp if they are closed replace the board. I don't know what you heater is but is pretty common for the board to receive a - 12 volt signal to the board from the sail switch. Frankly I would not change or modify design of the air flow to the switch and risk issues of too little air flow to the heater if the switch does not close there is a reason not only does expel hot exhaust it brings in makeup air.

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Everything works fine except sail switch wouldn't close fully. I got tired of reaching in the tunnel to trigger it. Once closed it stays closed. I haven't changed any airflow, just gave the sail a tiny bit more surface area and now it works perfectly.

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33 minutes ago, canman47 said:

Everything works fine except sail switch wouldn't close fully. I got tired of reaching in the tunnel to trigger it. Once closed it stays closed. I haven't changed any airflow, just gave the sail a tiny bit more surface area and now it works perfectly.

Well it kind of means something isn't right it probably worked for many years without tinkering. Weak motor? Bad switch?

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It's never worked since I owned it. Always had to trigger the sail switch manually. New motor, fan, and sail switch. There's not much more to it. Don't know if previous owner ever used it.

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