Stokermatic coal stove - switch issues, need some help

Just sent you another private message.

I would go to Grainger supply or something similar...they should have this switch. I think the 10 amp one is just fine for now but would be a good idea to get the right one later.

Something I noticed right away and just now am going to mention, since no one yet has mentioned, is I don't like the looks of the resistor located on lower left temp switch.



Sure looks to have cooked the insulation on the coiled wire there. If so, that would be the bigger concern at this point.

McGiever wrote:Something I noticed right away and just now am going to mention, since no one yet has mentioned, is I don't like the looks of the resistor located on lower left temp switch.

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Sure looks to have cooked the insulation on the coiled wire there. If so, that would be the bigger concern at this point.

Yes, McGiever - you're onto something there....

After chatting with rockwood this afternoon, I believe that some portion of that limit switch is faulty; here's what we were able to determine:

First off, the wall thermo switch has full voltage (120v). This runs to the same switch that is controlled by the hold fire unit; when the wall thermostat is turned up (thereby calling for heat), this tells the auger/comb fan to get busy. What we noticed is that once the stove was burning away, the stove would shut down, and be unresponsive when the thermo was turned up. HOWEVER - once I manually turned on the circulation fan for just a few minutes, the stove would cool enough to allow the thermo's demand for heat to kick on the auger/comb fan. Does that make sense?

The unresponsive limit switch is not calling for the circulation fan when it should (which cools the stove) - which makes the stove stop burning too early, which leaves the firebox full of half/poorly-burned coal....and that's where we came in on this whole show. We've now come full circle. It was the faulty main power switch that got me there, but once that was repaired, we've discovered the faulty limit switch, which is/has been causing the entire mess that began the owner's complaining. Phew - we took the long way around....but we got there.

Now - I'll make a few phone calls tomorrow and see if we can chase down a replacement switch. McGiever - you've definitely identified something sketchy in that coil/limit switch. Hopefully we can find a suitable replacement relatively soon and get this thing back to 100% functionality.

Monster big thanks to rockwood for his help this afternoon. If everyone else on this forum site knows what heh knows, then there's a WEALTH of information to be tapped into around this place!

I'll keep you all posted on what I find this...

I'm glad Rockwood put a saddle on this and really helped, but you are real good neighbor for fixing this.
Welcome to the board.

Well boys, after a few phone calls, I've found no luck with the replacement fan switch. At all. The responses I've had so far lead me to a grim conclusion.

Any suggestions? Is there a Stokermatic boneyard somewhere? How do I get this thing back on track?

Our plan is simple for now: place a small box fan directly behind the stove and let it blow enough air over the firebox to keep the temps down to a safe level. I think this will work fine for the time being, so she's not going to be freezing - AND the coal will likely burn tremendously better. That's a double win right there.

I had hoped, however, to come up with a more permanent solution than this. I can definitely address it over time now, especially that the fan main power switch is functioning as it should be.

How can I install a new(er) fan switch in this ol' dog? Anyone ever done this before? Got to be a way, right?

I've spoken with Annette over at Stokerworx, and also the gentlemen over at Pease. Neither had any ideas/suggestions on where to go from here. I've also posted a "wanted" ad over the classifieds section of this forum, and have also been perusing eBay with my fingers crossed....but to no avail.

Anyone have a good idea?

Thank you in advance, everyone. This place is AWESOME.

I'll take a shot, How about the fan switch from an old oil fired furnce. It has a coil in side that turns a dial with the high and low temps on it. I think it fits in a 1" hole but not sure.

Just about every wood furnace made comes with a plenum switch that is line voltage(120) that turns the fan on and off when the temp gets up to temp.

crazy4coal wrote:I'll take a shot, How about the fan switch from an old oil fired furnce. It has a coil in side that turns a dial with the high and low temps on it. I think it fits in a 1" hole but not sure.

That's what my furnace has now. He may have to convert to this type.

Sounds good - where do I find one?

Sent you a private message when you started the other thread in the for sale section (can't reply to those)....didn't notice your reply here before I sent it

I haven't replied thus far because I'm both not familiar with the electronics on that stokermatic and I would have taken a different and more costly approach to the whole situation.

To rely on an older appliance for heat is one thing; to rely on an older appliance that has failing, incorrectly wired, faulty, and obsolete electronic components is another. I would have yanked that mess out of there entirely. I would replace everything but the timer. Use new wiring and relays, a simple fan/limit switch and be done.

RELAY: http://www.newark.com/omron-industrial- ... -J-CB-AC24

You can use snap switches in place of a more expensive combination switch

Or you can use a combination fan/limit control: http://www.pexsupply.com/pex/control/se ... %20control

I think it's the limit switch. My furnace has a different, more modern type and gave him suggestions on where to get one.

Here's the type switch on my furnace. http://inspectapedia.com/heat/Fan_Limit ... 76-DFs.jpg

Just a tid bit of info...those 2 temp switches shown in the pics are older style switches used commonly in electric hot water tanks to switch on and off the electric elements.
They are technically just a adjustable temp switch that make physical contact on they're back side to sense that surface temp.

They are not really unlike the modern version of today. The (burned up) resistor however, is unique to this coal stove application.

Also, the suggestion of the addition of the combination fan/limit for circulation fan is a good one. The big question to adding the fan/limit is, where to locate it???
Results from locating it can change the response time to the heat that is present at that particular chosen spot. In other words, it could respond too quick or too slow causing a shorter or longer blower cycle. It will be a change from the designed *stove metal contact* to a now *air stream* sensing.

Hard to advise you as to where to locate it, but I will try to help some, you want it to sense a good average heat but not be effected too rapidly by the fan when it comes on.
I would say closer to one side as opposed to in the center...unless this contradicts what I have already stated.

McGiever wrote:Also, the suggestion of the addition of the combination fan/limit for circulation fan is a good one. The big question to adding the fan/limit is, where to locate it???

If he gets the same fan/limit control that I have, he should be able to install it in the same location as the original. On my stoker, which is a newer model than this one, is installed between the heat exchanger and the hopper. It is about half way up(maybe higher) the heat exchanger and is sitting against the foil backed insulation which is about 2 " from the heat exchanger.

It works fine for me in this location.

Also, it is the 11" insertion model fan/limit combo.

OK - I have some catchin' up to do here....and a few messages to reply to, but here's just a quick update on what's going on with this thing:

I want back over on Tuesday afternoon and hardwired the fan to come on whenever the main power switch was set to "heat". She wasn't comfortable with leaving a box fan behind the stove and just letting it run, so I hooked it up to just fire up every time the main switch turned on. I thought that would solve a lot of the poor-burning and overheating issues, at least for the immediate future.

I was wrong.

The fan comes on and blows all the time just as it should. However, the poor-burn issue is still alive and well, and now the auger/motor combination is really acting up. I've been back over there every night trying to "influence" the auger/motor to start up. The first night I took a small crescent wrench and slowly turned the auger, and it came right to life once I flipped the switch. Last night, I flipped the switch and light popped the electric motor with the heel of my hand...and it spun right up. Not sure what all of that means - does she need to replace the motor? It doesn't look very worn at all, but perhaps it's not putting out enough torque to kick things off? Is there something getting caught in the auger? Not sure what's going on. I just touched base with her over the phone, and it's been alive now for close to 24 hours, the first time since last weekend. Not sure it we're just getting lucky or if perhaps whatever it was has purged itself. Could be anything, I guess.

We have also recently run across replacement stoves, both at/near the $500 range, but not sure that's really the best use of the resources either. Both stoves are 20+ years old, and one is over 200 miles away. Might be just robbing Peter to pay Paul, so to speak.

There have been a few of you who responded with some wiring info, and I've just not had the time to dedicate to it all just yet, but hopefully this weekend. I'd love to spend $100 and get thing back on track (plus not have to deal with chimney, wiring, new thermostat, not to mention moving this beast!), as opposed to having to deal with a replacement, but honestly that might be the best route for her. At 74 or 75 (I can't recall exactly how old she is) I'm not even sure schlepping coal and coal ash is the best thing for her anyhow. Don't know what would really be any easier, though, other than straight electric (and then her bills go through the roof - ugh).

I appreciate you guys hangin in there with me.