Aux-heat mod for Englander pellet stove

We are finishing up our 2nd season of having the Englander 55-TR-PEPI and learn a bit more each time.

We have a heat pump for the house, which generally does really well by itself, but it struggles a bit when temperature gets below freezing and it calls for the heat strip more than we would like. The pellet stove is a nice aux heat, but I need be around and awake to start it, and it can get too hot, or keep running when it warms up (need to remember to shut down). Both cases waste pellets.

I've tried the Hi/Lo setting with an external thermostat and it still has some of the same issues as above. Running a helper fan helps get the hot air into the other rooms and the A/C return, rather than having a very hot room where the stove is. The fan can be a bit loud, though.

For next season, I have a new setup that should reduce our pellet use significantly and only run the stove when it gets down to freezing (or whatever temperature I choose). It will also only run the helper fan when the stove is on.

I changed to on/off on the control panel connected an outdoor thermostat. When it gets cold, the stove and the fan come on.

One of the outlets is always-on. The other is on when the outside temperature is below 33F (42F for testing). There is also a relay that is hard to see in the back/left of the blue box that connects to the thermostat connection on the Englander control panel.

I had also tried to tap off the convection fan from the control panel, but that is a variable output depending on whatever the fan speed it set for.

Now I have to wait for a last-gasp cold snap, or next year to see how well it works.

 

I have heard of using outside temp. before,and in your case,appears to be an excellent idea.

 

Bright idea but the only downfall I see if the below temp is short lived. The stove might just start to make heat and off it goes, might only be that way during the beginning and end of shoulder season. Otherwise, the little wastage of pellets will be overided by the effective bright idea behind this neat gizmo

 

The tstat has an adjustable deadband. I actually set the off temperature and the delta. For right now, that's 35F for the off temperature and a 2-degree delta. It will call for heat at 33F (35-2) and turn back off when the temperature gets back up to 35. I can adjust that as needed, maybe even something like 38/5. Not only does it have to get cold enough, it also needs to warm back up before it turns off.

There's also the whole need to turn the stove on before the tstat will control it. If it's not the season, the stove isn't even on.

 

I was wondering if a swing was present in this gizmo and it does
Does the stove just get cut off the 120v supply and the fire dies out without the exhaust fan assistance is the question?

 

No. I'm not a fan of brute force (well, sometimes...). One of the outlets is on full time and that goes to the stove. The other outlet, and the additional relay for the thermostat control, are only on when the outside temperature calls for it.

 

Now that the mockup works, designing the final case for printing.
Large gray box, bottom left: the controller.
Box on the bottom/right: duplex outlet
Box on the top/left: relay
Cylinders on top/right: power cord and fuse holder.
Holes on the left/top: for the temperature sensor and the thermostat output

EDIT: re-arranged the box a little it.

 

Makes perfect sense, 120v on thermostat section only= brilliant idea

 

It didn't get super cold (down to 30F) last night, but MrsRojhan@ and I woke up to a cheerfully toasty pellet stove this morning, with helper fan running.

 

An a successful shutdown as well. "It works!"

 

Concept -> prototype -> finished. I need to find some terminal blocks for the thermostat and thermometer. My box-of-stuff is out.

 

I found some terminal blocks, so really done now...

 

I should have mentioned price. Less than $30 overall, plus design time and tinkering.
$16 for the controller, $6 for the relay, $2 for the outlet. A couple of bucks for the fuse holder and misc hardware, plus stuff I had laying around. About $1 worth of plastic for the 3D printing.

 

Nice work.

 

You my man did fine work

 

Finishing touch. Instead of just having the sensor sticking out the wall, I printed a holder for it. I just happened (really ) to have some paint that was really close to the color of the siding. It almost looks like it's there for a reason. Yes, I know that close to the house won't have accurate temperature, but it will definitely be close enough for what I'm doing.

It got a little chilly overnight and the stove started up again, as expected. It ran for about 4 hours before the outside temperature was warm enough to let it go back to sleep.

 

We haven't quite left winter totally behind. There's been a couple of days where it's dipped down to 29-33 or so. This morning it just touched 31 and the stove ran for about 2 hours. So, the delta on the thermostat seems to work well for the shoulder.

I'm literally on the last bag from the pallet we bought. I may run the stove to empty to make it a bit easier to move for end-of-season cleaning. 40lbs of pellets or so makes a difference.