KAA-2 feeding after power outage..

Is there a way to prevent the boiler from feeding coal after the power returns from a short outage? Went to work and there was a brief power outage that was long enough for the fire to go out. When the power returns the stoker resumes feeding coal. Is this the way it works or is there something not setup right? Needless to say, the hopper empties itself into the ash pan area....

They make a device for industrial and worksite machines, mandated by OSHA, that disconnects power when the power goes out. Or, it will not allow a table saw to come on unless the device is reset. You can find them online I would imagine.

Kevin

That sounds like a good solution. I don`t care about the fire being out because the oil boiler will take over till I get home, just the coal being dumped isn`t so great!! Thanks KLook.......

I think it is a magnetic switch. I have them on my 220V tools in my woodworking shop.

A simple DPST 120v relay would work, you just need a switch to energize the coil initially. One set of contacts will power the stoker, use the other set to feed power back to the coil. If the power cuts out (even for a second) the contacts will open and stay that way until you hit the "start switch" again.

Very clever Rob. Thanks.

Kevin

You may want something with a bit of a delay. I know my power drops for a few seconds several times a month and I would not want to come home or wake up to no fire that often. Possibly a DC powered relay with a capacitor would hold through a short power outage.

If it was a stand alone setup I would agree, but most of us with boilers have the old system as backups. Redundancy is a good thing. I guess i would use the UPC or battery backup systems with an inverter if that was a major problem with a stand alone system.

Kevin

It is easy to make a simple system overly complex. For me, I'd rather take the chance of having an ash tub full of coal once per year than having a device intended to prevent that very thing lock-out the boiler after a 5 minute power blip. Depends on your goals I guess.

You can use any 'manual reset aquastat' HOWEVER, if the power 'blinks', you are shut down...that sucks. How many times will the power fail and fill your hopper in a season? Probably once, perhaps twice. Is it worth the aggravation to wire up something 'space age? I say: NO! 75 lbs of unburned coal is nothing compared to a big bin that has 8 tons you might have to shovel to get to the bottom of the bin and the auger!

You cold add an inverter and a battery pack...a generator with an auto-start transfer switch......or just bitch about it once in a while. It is NOT like shoveling a 20 ton load of 1 1/2" stone. Man-up! Jessssss!

While it is easy to get it overly complex a simple motor starter or DPDT relay is the circuit you want, the momentary power drop out will be a big annoyance. A solution is to put a UPS or equivalent on the relay circuit. Doing so means the UPS like, device only needs to have sufficient energy storage to power the relay. The coal appliance will stop working during the power interruption, but the relay will stay in the on position for as long as the UPS has power storage.

For example you could use one of the many electronic junk DC "wall warts" you have laying around. With an relay having the matching coil voltage, you wire one pair of the DPDT contracts to power the coal appliance. The other set of contacts is wired as your drop out circuit control. The drop out time delay is now set by how long it takes the "wall wart" DC output to discharge below the relay coil hold-in voltage. A tinkers delight solution to a common problem.

I guess I could have explained better but the wall wart solution was what I was thinking. The discharge of the DC filter capacitors from most AC to DC converters should give you a few seconds hang time. If it is not long enough just add another capacitor. Having a back up heat sorce is great but having to relight a fire after work several times a year just because the power hickuped for a second is worse than having to shovel a bit of coal once in a blue moon. Especially when you know your "fix" for one problem is the cause of that one.