I have a pellet stove in my living room that works great. If I run the furnace fan, it works even better to circulate the air around the house. So I decided to connect something up that will automatically turn the furnace fan on when the pellet stove is running. Below is a schematic of how I have accomplished this.
In summary: I installed a 120VAC relay in the pellet stove connected in parallel to the combustion fan. The combustion fan runs continuously while the stove is on - during the ignition cycle, heating cycle, and cool down cycle. The contact sides of the relay connect to an Altronix 6062 timer. The 6062 timer connects to the "green" and "red" wires of the furnace thermostat to run the furnace fan. The purpose of the 6062 is to give a 20 minute delay in turning the furnace fan on - gives the stove time to ignite and warm up the room a little. When the stove is turned "off", it takes about 30 minutes to cool down, then the stove shuts off completely. At that time, the 120VAC relay opens and shuts off the furnace fan immediately. This works perfectly, sort of...
So this is my problem. When I press the button on the pellet stove to turn the unit off (and start the cool down process) the combustion fan must shut off for a half a second because I can hear the 120VAC relay click off and on really fast. This unfortunately resets the Altronix 6062 timer and shuts off the furnace fan. The furnace fan does come back on 20 minutes later (because the 6062 had restarted the time delay) but by this time the room is already cooled down. I was thinking of placing a capacitor in parallel with the + and - terminals of the 6062 timer. This way when the pellet stove quickly cycles power on the combustion fan, the 6062 doesn't see that quick voltage loss, and does not reset itself. But I'm not sure of what value capacitor I should place there or even if this is the right direction to go. Any thoughts would be appreciated.
NOTE: I did realize I have the green wire from the furnace on the NC contacts of the 6062, should be on the NO contacts. Just an error on the schematic.
Altronix 6062 Question
Re: Altronix 6062 Question
Sounds like you're on the right track. As to the value of the cap, that would depend on the current draw of the timer board, and the amount of time. I would try something in the 1,000 microfarad range first and take it from there.
Re: Altronix 6062 Question
Try this arrangement. Value of the cap will depend on the current draw of the 6062. Start with a 470 uf as shown and experiment with larger or smaller as needed.
Steve G
Steve G
Re: Altronix 6062 Question
The current draw listed on the cut sheet is 40mA with the relay energized. As far as the time, I really only need it to keep the timer active for only a second or two. Thanks for the help!
Re: Altronix 6062 Question
Yes, a cap will solve that problem!
I tried that timer with a 3,300uv/25V capacitor accross the timer's power terminals and it kept the timer powered up for about 3 seconds which is probably long enough to handle the relay's blip. The timer's relay is the large power load so that cap needs to be pretty big.
Side Note: Would a thermostat to sense the stove's temperature be a better option than the furnace fan's delay timer? Maybe a simple snap action thermostat would simplify everything! Route the control voltage through the present fan relay and a thermostat.
Stove fan starts....Stove heats....Thermostat closes....Furnace fan starts....Stove fan stops....Furnace fan stops.
Len
Question: Steve G... Why the diode in the revised drawing, the power is 12VDC?
I tried that timer with a 3,300uv/25V capacitor accross the timer's power terminals and it kept the timer powered up for about 3 seconds which is probably long enough to handle the relay's blip. The timer's relay is the large power load so that cap needs to be pretty big.
Side Note: Would a thermostat to sense the stove's temperature be a better option than the furnace fan's delay timer? Maybe a simple snap action thermostat would simplify everything! Route the control voltage through the present fan relay and a thermostat.
Stove fan starts....Stove heats....Thermostat closes....Furnace fan starts....Stove fan stops....Furnace fan stops.
Len
Question: Steve G... Why the diode in the revised drawing, the power is 12VDC?
Len
“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)
“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)
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Re: Altronix 6062 Question
a therm-o-disk would make things a lot simpler, when it gets hot enough it turns on.
when it cools down it turns off..
and simple 2 wires..usually they can handle as much as 10 amps.
when it cools down it turns off..
and simple 2 wires..usually they can handle as much as 10 amps.
Re: Altronix 6062 Question
Len,Question: Steve G... Why the diode in the revised drawing, the power is 12VDC?
Actually the diode is not needed. When the relay contact opens up the only path for the cap to discharge is through the timer dah.
I'll edit the schematic.
Steve G
Re: Altronix 6062 Question
Thanks again. I'll have to dig through my parts bin and find a couple of capacitors to try, but if I have the 3300uv I'll use that one first like Len suggested. It's actually been a little warm here the past couple of days so haven't fired up the pellet stove, so hasn't been a priority to address this yet.
It didn't even dawn on me to use an internal thermostat for some reason. I just figured if I could hook up something that would monitor when the stove was on, that would be the trick. There are three sources I figured - the combustion blower (exhausts air out of the fire box), the convection blower (blows air around the fire box to heat the room), or the auger motor (feeds the pellets into the burn pot). The auger motor was out because it cycles on and off continuously and I would hear the relay click on/off too much. The convection motor would have been nice, because it doesn't turn on right away, but after the stove heats up. What I didn't like about it was it has a high/medium/low setting and the voltage ranges from 120V-90V depending on speed. So that's why I went with tapping off the combustion motor. In fact, I've made it 100% reversible with the only permanent modification to the stove is a screw hole for the relay socket screw. The only other thing I though I could do was somehow monitor the current on the hot power lead with a current clamp. But that seemed too complicated for what I was trying to accomplish - plus I already had the 120V relay and 6062 timer in my supply so my cost for this project was basically $0. The other way around I would have to buy more parts!
But it's funny you mentioned that diode. I kept looking at that diode in the schematic, scratching my head trying to figure out why I needed it there. Didn't see any voltage backfeeding anything so had me stumped. Figured I'll come back to it another day. Just didn't need it after all!
It didn't even dawn on me to use an internal thermostat for some reason. I just figured if I could hook up something that would monitor when the stove was on, that would be the trick. There are three sources I figured - the combustion blower (exhausts air out of the fire box), the convection blower (blows air around the fire box to heat the room), or the auger motor (feeds the pellets into the burn pot). The auger motor was out because it cycles on and off continuously and I would hear the relay click on/off too much. The convection motor would have been nice, because it doesn't turn on right away, but after the stove heats up. What I didn't like about it was it has a high/medium/low setting and the voltage ranges from 120V-90V depending on speed. So that's why I went with tapping off the combustion motor. In fact, I've made it 100% reversible with the only permanent modification to the stove is a screw hole for the relay socket screw. The only other thing I though I could do was somehow monitor the current on the hot power lead with a current clamp. But that seemed too complicated for what I was trying to accomplish - plus I already had the 120V relay and 6062 timer in my supply so my cost for this project was basically $0. The other way around I would have to buy more parts!
But it's funny you mentioned that diode. I kept looking at that diode in the schematic, scratching my head trying to figure out why I needed it there. Didn't see any voltage backfeeding anything so had me stumped. Figured I'll come back to it another day. Just didn't need it after all!
Re: Altronix 6062 Question
Well, got a 3,300uv capacitor in there and works perfectly! I ended up having to order one because I actually didn't have any capacitors in my parts bin close but gave me an excuse to order some extra stuff from them, so we all win!
Thanks for the help!
Thanks for the help!
Re: Altronix 6062 Question
Another success for 'Get-er-done' technology!
Len
“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)
“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)
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