Thelin Parlour repair

In 2006 I swapped out a fairly efficient, forced-air, propane wall heater for a Thelin Parlour 3000. I've had a few issues over the years and I've done a fair amount of research through forums like these and decided to document the current problem to add to the scarce available information out there.

We live in a small house in the Sierras and it gets pretty cold here but, cold is relative. Some nights in e the winter we get into the mid teens but, mostly, it's in the 20's and 30's. The Parlour is oversized in BTU's for our humble abode but, we have a 2 story, drafty place and it is our only heat so, I did it that way in purpose for the really cold times. We burn about 1.5 tons a winter.

The igniter lasted until about 2010ish. Maybe 3 years of usage. The replacement being around $200 and the abundance of manual start up methods led to me never replacing it. I don't know about other stoves but, this stove has always had "clinkers" and I couldn't put it on a thermostat if I wanted to due to that and so, manual start ups are far better than $200 for an igniter.

2011 had me troubleshooting it for real. Low whining noise from the fan got louder all the time. The stove was rarely turned up above low up to that point but turning it up to Med/Hi quieted the whining. Finally, it got so bad I began looking into repairs and discovered the tiny little brushes on the motor were all but gone. The cost of the 2 brushes from the dealer was $40. Forty. American dollars. Forty.

The whining was never completely gone but it was far better and obviously the major issue with the stove. I assumed the remaining noise was bearings but not worth my time for the noise was so low. Over the next few years, the whining and sporadic surges I could hear at night when everything else was quiet led me to believe the fan motor was due to get replaced. In 2013, I started shopping for a fan motor. They are smaller than a can of soda but priced as if they contain platinum. The cheapest motor I could find came attached to a convection fan plate assembly and it was $425. I put the new fan assembly into the stove just before the 2014 winter thinking the whining would stop. That brings me to this point...

After replacing the fan with the newer assembly, the whining was a tad quieter but not by much. I figured the reduction in noise was due to the new bearings but, I was puzzled about the now annoying whistle in the thing. More importantly, I was becoming furious over what I believe to be obvious price gouging with parts. The new motor has a capacitor pack pre-installed on the bottom, in case you're wondering. The dealer that sold it to me told me it is there to reduce wear on start up of the fan. OK. "Is there a whistle installed in it too?"

After I replaced the fan assembly, I was glad I bought the entire assembly. Getting the combustion fan off is easier said than done. I haven't yet done taken apart the old one but I will. To build a spare up.

This winter, I have laid awake at night listening to the whining noise and the slight fluctuations in speed, knowing full well something was wrong with it. Now, on start ups, the fan was spinning just fast enough to get the flame going was all. I'm the curious sort and thought maybe if I removed the auger leads then I could isolate it from being an issue. Maybe it was putting undo load on the whole circuit. So I removed the heat shroud and various parts to get to the auger. (This is easier to do than you think, for those who may be contemplating it) Removing the leads from the auger produced no change in noise or speed from the fan.

I then read where you can actually adjust the voltage being sent to the fan. There are fan trim adjustment you can make with a tiny flathead screwdriver. They appear on the lower right corner of the stove control board. I adjusted them both up equally but they were near topped off already. Maybe half a turn was all. If you adjust the low end and not the high, you end up losing the medium setting in the fray. It helped just a little with noise but not much.

Then, during the night in Christmas Eve, the whine was awful and it was barely turning the fan at all. One of the routines I'd try in the past was running the fan on the "clean" option and re-trying to see if the fan acted better. Often it did. It did so again this night for about half an hour and then it was done. Barely turning at all, I don't want the motor to burn up so I'm now trying to troubleshoot.

The new motor has less than 2 years of usage. I will remove the brushes for inspection but I am certain they are not the issue. That brings me back to the old motor. I replaced the old motor entirely but, the issue was never really gone. I started wondering if the transformer was maybe not providing the proper voltage to everything. There are a couple decent schematics available from Thelin and I've been looking at them. I'm pretty good with a VOM so, I'm going to check voltages on the control board and see if I can't fry it or burn off my fingers now...

Lake Girl said:

Welcome to the forum! I take it the new motor did not get rid of the whine? Thelin parts are expensive...

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Yes, they're bad. And it being a holiday weekend, unavailable. I discovered the parts are now sold by a company in Carson City, NV who apparently bought Thelin or something. The parts through them are actually less than elsewhere.

So, I now realize how simple the stove actually is. Maybe they're all simple. I tore the back off already and had decent access to electrical components. Some are mounted to the removable bottom plate and, if you're inclined, you can tilt the stove carefully onto it's face and unscrew 4 screws to get unimpeded access to everything. I didn't want to remove it from the chimney connection so, I worked from the side.

I removed the control board 1st so I didn't burn something up on it, even though I was pretty sure it was my culprit. The fan motor has maybe a season and a quarter on it. I checked everything for proper voltage starting at the transformer. Good. Next, the rectifier. It's a small square mounted just in front of the transformer and has 4 wires terminated. Several wires are in your way if you access it the way I did. I bumped the exposed solder on top of the nearby negative fuse and blew it. The fuse is supposed to be time delayed but it went fast. Replaced. Verify rectifier at 18.5V DC leaving it and that's within specs. Next is control board. (I didn't bother testing the relay which is there for the igniter that I won't bother replacing so, I don't care about that relay)

I know how to use an VOM pretty well but I'm not an electrician or machinist. I don't know exactly what I'm supposed to see when I connect to things to motors so, I was scratching my head when I first connected the control board and plugged the stove into power. I disconnected the leads to the fan motor and auger and measured 12V on both with the switch in the "OFF" position. What the what??!! I left my test leads connected to the fan wires and terminated the leads to the fan and auger. 12V on the fan, zero on the auger now. I turn it onto the "LOW" setting. Voltage jumps to about 19V on the fan leads then, after a few seconds, drops back to 12V. I disconnected the fan terminations and tested it again. Same results. I let it run for 10 minutes or so. The control board should tell the auger to spit pellets at about the one minute mark but the auger never turns. I reterminated the fan and started the cycle again and this time, the fan started turning. Not good, but turning. After a minute, the auger began turning and I disconnected a lead from it so it wouldn't spew pellets for nothing. This told me that the control board was looking for a signal that the fan was actually running before it would tell the auger to start. It also told me that connecting the leads to a motor would bleed off the initial 12V that appeared on the leads if they weren't connected to a load. Lesson learned. I always test at least twice so I repeated the step. I see the 12V on the fan jump to 19 but it doesn't spin. I did that procedure 10 times and several of them had the fan spin and several didn't but I figured out that, before turning it on, if the voltage dropped all the way down to zero, the fan was going to turn when I turned it on. It also told me that the board was probably OK as it was always sending the proper voltages. The 19V bump I saw was the startup capacitor on the board giving the fan an extra push to start turning and meant that the capacitor mounted to this replacement fan was redundant. Now I'm thinking the motor or that capacitor on the fan is bad. Somehow, there was an intermittent open toward the fan...

I disconnected the chimney (grrrrrr.......) because this replacement motor has odd terminations. Instead of the connector posts protruding from the brushes, the brushes are under the screw caps and there are wires coming out of the motor housing. Not at all like the Pittman. The capicitor that is on the fan is a little crude. It is two white, blocks with exposed wires tightly twisted out of either end with connectors for the negative lead coming from the control board. I am now suspecting it's a high resistance open in those connectors or something. After I flipped the stove onto its side, I could access the motor fine. I tested the capicitor at zero ohms. I bypassed it anyway since the control board already has a capacitor and I verified the voltages on it. I turn the fan on, even as it laid on it's side after I draped a towel over the exhaust. It fired up. As I said, I always test twice. The 2nd time, nothing. Arggggh! The fan is bad somehow. The replacement fan that I paid dearly for and burned maybe 1.5 tons in is defective. But how? The motor winding terminations have cracked solder? My connections were fine. No way would it be the brushes on the motor. This thing has never sounded right so, it's not brushes unless they installed bad brushes. I may as well look at them anyhow. Worn down into nubs. Impossible!!

I bought this replacement from East Coast Hearth and, because the capacitor appendage was blocking the labeling, I called East Coast Hearth to ask about what the name or style of brushes these were. They don't have the blade termination and I figured it wouldn't be easy to find a direct match. I spoke to a nice gentleman at the number on their site but, he didn't know what kind of brushes they were. They don't sell that motor anymore. So I bent the capicitor assembly back away from the motor and used a small mirror to read the label. Midwest Motion Products. I called them and spoke to a real nice guy (for a Vikings fan). He couldn't provide specs for the brushes but said they won't rebuild it and wasn't sure I should even put it back into the stove. Mine wasn't the first call to them about this issue and most calls were "not friendly". The specs for the motor were, apparently, never fully vetted by Thelin or whoever bought Thelin and the current draw might or might not cause brushes to burn up quickly. There really isn't a current draw on these though and that motor is larger than the original. At least the housing is. I don't get it.

I ended up replacing the brushes on my old Pittman motor and reinstalled it after giving it a mild cleaning. I'll use it the rest of this winter. I'll need to get it rebuilt this summer but am not sure where to go for that yet. The dealer that sold me the stove had the brushes for my old motor and, after the Chrsitmas weekend, they were finally open today. When I went in I noticed they are no longer selling Thelin. Not sure anyone is. Eventually, I'll probably have to move on from the stove but, for now, I know it inside out, upside down. I went through the trouble of writing all of this down so that, maybe, another sucker like me will be amused or informed. If you bought a replacement motor and it's not the original Pittman, you'll likely have trouble.

hockeypuck said:

Also..is there still demand out there for replacement motors? Are they expensive?

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I imagine there is a demand but they don't appear to terribly difficult to come by. The problem is pricing. When I ordered a replacement it was well over $300 and it appears that it may actually never really be a viable motor. I'll keep it but it will serve only as a stop gap.
Also, you asked about the Pittman part number. Do you mean for the motor? The number on the label is:
14203C708-R5