US Stove 5500M, how to slow down feed rate?

[Rishar]

Sorry to hear that.

It's a tiny house situation. 350sq.ft. Well insulated. I've had to lower the feed rate quite a bit just to not broil myself.

If by chance you could give me some pointers, it would be appreciated. The link in your post no longer seems to work. I know I'm probably asking for a lot here.

 

[tlc1976]

How are you with electronics? I'm not a whiz but I can do some things. Obviously you're going to have to ground things.

For starters I got a Honeywell Heat-Only thermostat. Removed the anticipator. And backed off the screws to increase the temp swing, since the largest temp swing you can live with will minimize how much the stove cycles on and off.

The thermostat goes to a 12v spdt relay. Run 12v thru the thermostat thru the relay, so when it calls for heat the thermostat completes the circuit and sends 12v to the relay coil. You also want 12v to go to the COM relay terminal.

The link probably went to how to build a 12v single shot, 1 second 555 timer module. Took a lot of trial and error for me. You can actually buy these off ebay for super cheap. You need two, maybe get some spares, I don't know how good they are. Each of the NO and NC terminals of the relay, you will connect to the input of a timer module.

You will also need two 9v spst or spdt relays. Each of the timer module outputs you will connect to a 9v relay coil. From the COM relay terminal, you'll connect both relays together, then connect to an 80-100 ohm resistor, then to pin 7 on the stove board. The NO terminal of the main thermostat relay is for power on. So follow from the NO terminal of the thermostat relay, through the timer module and 9v relay that's connected to it, and connect the NO terminal of that 9v relay to stove board pin 4 (on button). Then connect the NO terminal of the other 9v relay to stove board pin 3 (off button).

(I would check these connections and the ohms with a multimeter before connecting everything else to it, since no guarantee it's the same 5 years later. Like probe pin 7 and 4, hold ON button, see if you get around 80 ohms or whatever. Same with pin 7 and 3 and the OFF button.)

All of this I built into a little enclosure, and powered by a wall wart with the voltage I described. You have to make sure it has enough voltage where it doesn't drag down and stop it from working, which I had to remedy early on, hence the 9v relays. I had plenty of wall warts laying around. I fastened the thermostat to the cover of the enclosure.

You also want the box somewhere away from the stove that you don't get false readings. Outdoor phone wire is cheap and makes a good connector from the 9v relays to the stove board. You could even get fancy and put some quick connects to make things easier.

I never did add the delay timer to the wall wart power supply, but if you have power outages it would be a good idea. Could probably find a single shot delay timer module off ebay for cheap. Delay it by maybe 30 sec. So when the power comes back on, the stove has a chance to boot up, then it "pushes" the on button. Otherwise it would "push" it immediately and it would do no good because the stove isn't booted up yet.

It's pretty simple really, especially if buying the timer modules. I could probably sketch something up but couldn't scan it tuntil I get back to work the middle of next week.

 

[Rishar]

Sorry it took me so long to get back. I've done my share of electronic repair but never built my own circuit. If you could do up a diagram I would really appreciate it.

 

[Matthewt]

Here we go. I guess I never clicked the more options button to find how to upload this. Photobucket doesn't work well for dialup.

This is mostly it, taken at my house before I took it over and installed it. I drilled two small holes in the bottom of the enclosure, one for the phone wire to the stove, the other for the wall wart power supply. Then the thermostat is screwed to the cover, centered to look nice. I also bypassed the anticipator because it really does no good for this application. Wish I had pics of it on the wall, and my hookup to the stove, but I was really under a time crunch to get it done and didn't have a camera. But my description should be self explanatory if you are ever into the panel.

The circuit is pretty much available online, I just had to apply it to what I was doing. The thermostat powers a relay to throw the power between the ON and OFF timers. Other than that, I originally followed another page which screwed me up at first but this page gave me perfect results.

http://home.cogeco.ca/~rpaisley4/LM555.html#29

Circuit 1 is the main circuit, except the output relay is wired NO instead of NC. As described earlier in the page, R1 is 1M ohms and C1 is 1uf to make the "button press" 1 second long which was easy enough. If it needs to be shortened or lengthened depending on the stove, just adjust the values of R1 and C1. I also put a .1 uf on pin 5 as recommended earlier in the page.

The wall wart puts about 15v and drags down to 13v during triggering. The thermostat relay is 12v because it is on during the whole heating stage and also is the first to receive voltage so no problems. The timer output relays are 9v, and only run 1 second at a time with a long time in between, so this makes them reliable when the voltage drops.

We have both been insane busy at work and yesterday was the first time I was over there in almost a month. But I checked it out and it is still working perfectly.


View attachment 81589

Wow someone else did this too. I did the same thing useing a Ardunio mico controller. Only difference is my is inside the stove with a two wire themostate connection coming out. I also have a older 5500m in my basement the control board went out of that stove so i use a bigger micro controller to power that whole stove. Both stoves work great. But the 5500 is so much cleaner then the king. It did take a lot of work and experimenting to make it work. But i glad someone else figured how to hook a real themostate to a king stove.

 

[Reallybichy]

Why not just hook it up to a thermostat so the stove cycles on/off as needed , thus eliminating the cooking you out of the house issue ? Plus you should save on pellets.

I wanted to ask that question if the stove is connected to the thermostat it will run according to the temp I set?

 

[tlc1976]

It's been a long time and I'm no longer with the person who had that stove. If you connect a thermostat according to the manual, it will maintain the set temperature as long as the weather isn't too warm for the lowest heat range. If you modify the stove like I did, it will maintain the set temperature by cycling the stove on and off when the weather is too warm for the lowest heat range.

 

[eckpeck]

@tlc1976 Sorry to jump in here, can I ask if I was able to post you a sketch I made following your directions would you look at it? I think I have it, and I understand this is an older post. Great reading, just bought this stove used and it works fine but did not realize that is is not like my other stove which Starts and Stops Automatically.

 

[tlc1976]

Yes if you post a sketch I will look at it.

 

[eckpeck]

ok here it is, its not the best line drawing but i need it to make sense in my mind

 

[tlc1976]

Here is my version. I’m a bit confused on yours but here’s how I draw it. If you were to get 555 timer / relay modules, then the 555 chip circuit and relay would be one integrated unit for on, and one integrated unit for off.

 

[eckpeck]

Thank you for taking the time, I appreciate it and I appreciate your sketch. My drawing well, I tried to cipher what you wrote up and I have very little experience in wiring up anything like this, I am determined to get this working one way or another. I found those 555 modules on ebay as well as the 9v relays, is that thermostat relay that same 9v or is it 12v? That's what threw me off. Sorry this does not come that easy to me

 

[tlc1976]

If the 555 module has a built in relay that it controls, then you don’t need the 9v relays. The reason I went with 9v relays instead of 12v is because of the voltage drop of it running the thermostat relay, the 555 timer, and push button relay all at once. I started with 12v relays but it didn’t leave enough to operate it all reliably. I don’t remember what milliamperes my wall wart was but it wasn’t quite enough. My goal was to build it with what I had laying around. I figured the push button relays were also very intermittent too so a slight over voltage wouldn’t kill them. The thermostat relay I kept at 12v because it sees power the entire time the thermostat is calling for heat which can be hours at a time, and besides the voltage will rise again once the “button press“ is complete. I didn’t want to cook the relay.

The pins 3,4,&7 are at a mini harness that connects the push button pad to the next layer of circuit board. There were 3 layers of circuit board connected with plastic standoffs if I remember correctly. Of course this was in 2012 so that’s why I say check it out first in case they made changes to the board since then. The resistor is to simply match what I measured from the push button pad. I don’t know how important it is but I figured it would be best to match it reasonably close. So if you measure something different then go with something close to that value.

So please check out the stove board first and be exactly sure where you will solder to. And please do a rigorous bench test of your completed controller before connecting it to the stove. Cycle the relays repeatedly by adjusting the thermostat up and down and make sure it does not fail. Once you know it’s all good then connect it to the stove and enjoy!

 

[eckpeck]

Thank you so much again for taking the time to answer this and the explanation. I will be sure to test the setup before i hook it up to the stove and measure everything prior, to make sure i do it right. Ill defiantly let you know how I make out.