Pellet stove potentiometer

First off I am a full rookie on any forum! so this might no make any scenes . I have a double stacked Potentiometer from a Envirofire EF4 pellet burning stove built in 1998. Switched off = open circuit or infinite, on low fire 800k ohms to 900k ohms on high fire 36.5k ohms. there are some numbers on this pot,here they are. On the outside 450S1441 9828. on the bottom CTS13 type GC 3A 125v 1A 250v. AC. This part has been discontinued dew to the age of the stove,but i don’t want to get rid of it because of one small part, what a waste.If there is anybody out there that can help ,wow that would be so great.

Welcome to the forum.

It is almost certainly a full or semi-custom assembly from CTS Electrocomponents.

These were easy to get in small quantities (<1,000 pieces) back in the 1990s so ended up in many niche products like this. Unfortunately the collapse of the entire potentiometer industry, do to better performing less expensive digital solutions, has made it very difficult to find odd ball triple gang assemblies (two pots and a switch). Way back you could open a CTS catalog and come up with a semi-custom part number from CTS for a 3 gang, 1Mohm/40kohm/switch with a large selection of options (shaft, bushing, terminals, etc.). I don’t think that is the case anymore, now you’d need to buy 10,000+ pieces.

If I’m imagining the operation of the system correctly, you may be able to use multiple components to duplicate the functionality in a less convenient way if you can physically fit them. (e.g. separate switch and dual gang pot or two pots)
To give more help on doing that I’d need to see photos and a description of how the system operates in detail (link to owners manual would be great).

I’m an old close to retirement engineer who worked in the precision potentiometer industry in the 1970s, so I don’t have a good feel for the what’s currently available from CTS. A quick look @ Digi-Key showed nothing even close, however one of the Digi-Key employees or another forum member may be able to find a triple gang 1M/40K/SW pot form some manufacturer.

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We do not carry any 3-gang pots. We do carry some of the CTS 450 series. Take a look at the link to see if you could make any of the work for you.

I have looked into this a little as well. Even thought I was unable find suitable options to offer on our website I did find a data sheet archived out on the web. I will share that below.

Link to data sheet (485.4 KB)

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Thanks so much for taking an interest in my little stove issue, like I said I have never tried to go on a forum before but this is amazing and I will be hooked for life. Here are some pictures and links to the owners manual.


ATT00001.txt (6 Bytes)


ATT00004.txt (23 Bytes)

Thanks for the extra information it allowed me to figure out the system.

The good news is that I believe there would be no safety concerns with replacing the the semi-custom pot with three separate components, two pots and a switch, I suspect there’s even physical space to mount them all. It would not be convenient to use but it should work.

The bad news is that the dual gang pot provides synchronization between two isolated circuits via the single shaft. So we’d have to find a two gang 1Mohm + 50kohm pot, and I don’t think those are available in reasonable quantities. Without good synchronization I suspect the stove would operate with very low efficiency and some combinations of pot setting could cause damage to the controlled parts.

I searched and found a 3rd party seller with the replacement part.

It’s a version that works for both 110VAC & 220VAC so there are some wires for 220V use that won’t be connected. Also it isn’t cheap at $150.00, but it will definitely work or you’ll get your money back.