Smart Thermostat - Koker Lite

 
Ttem27
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Hot Air Coal Stoker Stove: Keystoker Koker Lite
Coal Size/Type: Rice

Post by Ttem27 » Wed. Feb. 20, 2019 3:41 pm

Hey everyone,
I want to post a little info about a success story with a new thermostat for my Koker Lite. I was pretty determined to get a smart thermostat hooked up to my koker lite. Mainly because I travel alot and am sick of having the stove throttled down and coming home to a cold house. The smart thermostat would allow me to throttle it back up before I get home allowing me to come into a warm house.
Anyway, there's very little information regarding a smart thermostat, coal stoves and wiring it to the R89A transformer on the Koker Lite.
So, let me put it this way. Most smart thermostats require a 3-wire system, most of the koker lites I've found out are heat only, 2 wire (normally red, white) systems. The 3rd wire or common, allows constant power to the thermostat to power the electronics of the system. If you have the R89A honeywell transformer on the back of your coal stove, there is no terminal for a constant 24v wire to run back to the thermostat. Therefore, running a wire defeats your purpose because there is no where to power it.
After some research, and having the ability to do so. I found a 24v AC/AC transformer that will plug into a standard 110v outlet. It's available on Amazon for approx. $15. It comes with 2 wires that will then plug into the C and RC terminals on the thermostat side, allowing you to power the thermostat. This allows you to have a smart thermostat.
To sum all that up, if you have a standard outlet nearby your coal stove thermostat you can use this plug in transformer to power the smart thermostat.
Just wanted to put this out there in case anyone had the same idea I did with no luck.
Furthermore, the NEST thermostat I purchased, comes with room sensors. These can be placed around the house to monitor temps in different rooms. You can even set the coal stove to come on when the temp drops in a room where your thermostat is not.


 
mike2007
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Post by mike2007 » Sun. Nov. 08, 2020 7:50 am

if doing what ttem27 is doing, question is where do you wire the red and white wire from the coal stove into the nest??

 
Ttem27
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Hot Air Coal Stoker Stove: Keystoker Koker Lite
Coal Size/Type: Rice

Post by Ttem27 » Sun. Nov. 08, 2020 7:57 am

Let me take a look in a little while and I'll get back to you. I'll try to take some pictures. It worked great for me all of last year.

 
mike2007
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Post by mike2007 » Sun. Nov. 08, 2020 8:55 am

thanks I have the 24 volt transformer hooked up for the c wire and I think the white wire, and the red wire from the stocker, but haven't got a clue where to hook up the return white wire for the stove. thanks a lot

 
mike2007
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Post by mike2007 » Fri. Nov. 13, 2020 11:56 am

well after going around and around, I remembered I had a backup sr501-4 switching relay from my old stocker, it's the same as the ra89a. it still had the instruction sheet, the first item under troubleshooting say. digital thermostats do not work correctly when connected to a switching relay. they go into great detail how to add a 1000 ohm 1/2 watt resistor to work with most models which is probably beyond my expertise since I need to start up the stove in a few days. so not sure how to get it going with a nest, to bad. interestingly the sr501-4 does have a c wire that should have made it easier If I had time to replace the 89 with the 501.

 
Ttem27
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Hot Air Coal Stoker Stove: Keystoker Koker Lite
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Post by Ttem27 » Sat. Nov. 14, 2020 8:58 am

Sorry it took me so long...work stuff in the way this week. I literally just got in my door. I’m heading down to grab a picture right now

 
Ttem27
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Hot Air Coal Stoker Stove: Keystoker Koker Lite
Coal Size/Type: Rice

Post by Ttem27 » Sat. Nov. 14, 2020 9:05 am

Here’s the setup

Attachments



 
Ttem27
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Hot Air Coal Stoker Stove: Keystoker Koker Lite
Coal Size/Type: Rice

Post by Ttem27 » Sat. Nov. 14, 2020 9:08 am

W1 and RH come from the coal stove. C / Rc are from the transformer that goes into regular 110 outlet

 
mike2007
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Post by mike2007 » Sat. Nov. 14, 2020 9:25 am

yes thanks, my problem was I checked out all the information, and bought the one that said you could hook up a two wire furnace, the fact that you wouldn't have power was not mentioned. once I went to the 24 volt transformer, I now had no place for the R wire from the stove, I only have one R not a Rh and Rc. I found a write up from a nest installer that said you could just block off the r wire and use the w wire and the transformer, that doesn't work, so being late in the season just going back to the old thermostat. thanks for the help!

 
Ttem27
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Hot Air Coal Stoker Stove: Keystoker Koker Lite
Coal Size/Type: Rice

Post by Ttem27 » Sat. Nov. 14, 2020 9:41 am

No prob. If I’m understanding you right, power was also my problem. I ended up buying the 24v transformer from Amazon and just have it plugged in to a regular outlet. I’d be more than happy to guide you through it for next season. Honestly has been one of the best investments I’ve ever made

 
mike2007
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Post by mike2007 » Sat. Nov. 14, 2020 9:42 am

do you remember which one you have, I have the nest-e

 
mike2007
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Post by mike2007 » Sat. Nov. 14, 2020 9:43 am

I'm heading up to home despot, to get one of the newer ones I guess, thanks

 
Ttem27
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Posts: 27
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Hot Air Coal Stoker Stove: Keystoker Koker Lite
Coal Size/Type: Rice

Post by Ttem27 » Sat. Nov. 14, 2020 10:10 am

Fairly certain it’s the 3rd gen

 
mike2007
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Post by mike2007 » Sat. Nov. 14, 2020 1:55 pm

thanks I just got one will try it tomorrow

 
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Richard S.
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Post by Richard S. » Sun. Nov. 15, 2020 6:54 am

mike2007 wrote:
Sat. Nov. 14, 2020 9:25 am
yes thanks, my problem was I checked out all the information, and bought the one that said you could hook up a two wire furnace, the fact that you wouldn't have power was not mentioned.
The Nest and I would presume some other thermostats have or had small rechargeable battery they can utilize when no C wire is present. It's not a problem during cold weather, every time the system comes on it draws a little power to recharge battery. Where the issue starts is during mild weather where calls for heat are infrequent and short. I know when they came on the market they were having problems with dead batteries which of course prevents system from running. They tried fixing it by drawing a little power that should not be sufficient for the boiler/hvac controls to detect but a lot of them were so they were going on and off frequently. Not sure what the current state is.

It's a matter of marketing meeting reality. They market it as green product and the simple fix for no C wire would be regular replaceable batteries....which is not environmentally friendly. I'd imagine they also use a lot of power for wifi operations and would require frequent battery changes.


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