Hi, I've got a battery back-up system for my Harman pellet stove. Works like it should, no problemo! I've just acquired a Fahrenheit 50f furnace and it's not behaving like the Harman, ditto! Here's the set-up I have; Iota 30A tranfer switch, TBS 600-12 puresinewave low frequency inverter, Cotek charger and two Trojan 6 volt batteries in series. The pellet stoves and a light is connected to the system. The TBS inverter has a Automatic Standby mode(ASB) which checks every second for a load to automatically turn on. Works well with the Harman stove which a slight dip in electrical supply doesn't stop it from continuing running. But with the Fahrenheit furnace and a slight dip in electrical supply, the furnace goes into a shut down mode. Not fun to come home to a cold house with the furnace down. There's a remote switch on the inverter and I tried hooking up a fail close(on) relay but the furnace still shuts down. I was thinking of adding a capacitor set-up to buy me 2-3 seconds of electrical power to soft shut the power but giving my inverter time to kick in before the power dips or stops. Can this be done? Or suggest something else? Thanks in advance
Sorry I missed this. You could try a few caps but before assuming it would work 100% on a slight power blip try wiring some capacitors directly to an extension cord on your normal AC (I'm assuming you're competent electrically with the above post - capacitors will hold a charge be careful) with an extension cord unplug and replug briefly to see if the boiler/stove board will stay awake long enough for a subtle line disturbance. I have some VFD's that will run for 10-15secs after a 480V 3ph disconnect is opened
Is there a size of capacitor to look into. I only need a 2-3 seconds duration. The added V's on the capacitors do any harm to the control board is another question. Is there a reducer for the voltage that could be added to soften the blast of V's?
Can't do that. capacitors cannot store AC, only DC. In fact, a capacitor hooked in parallel the way you describe will act like a direct short on AC. How much drama that will entail is unknown, but trust me it will not work and might be dangerous. Can a computer UPS work? I think they are very fast acting. Perhaps you can feed the UPS from the inverter, so that the UPS takes over immediately, but the inverter is a more long term solution to the power outage. No guarantee that the UPS and the inverter will play nice together, but if the inverter puts out a pure sin wave, I think it will work. Greg
*Most* consumer grade UPS units supply power to the computer from the battery and continuously recharge the battery. There is technically no reaction time because the computer is always running off the battery. This is good for computers because they have 0 tolerance for power interruptions, but hard on the batteries of the UPS (only good for a couple of years). I'm not sure if newer ones are different, but as of 3-4 years ago that's how most of them worked. This is probably not the case for higher end enterprise models though.
So it seems I might have to try a computer UPS and see if it performs to my needs, if not the computer will have a upgrade
Trying out a computer UPS is in the works. If it doesn't, it will be a computer upgrade and back to square one
Sounds like the voltage/amp dip is enough that it falls below the minimum operating parameter of the furnace system - not enough reserve for the blower motor/s inrush current at start up ( not always stated on the labels) but could be up to 3 times the listed draw. Worn or dry bearings will significantly increase the start up draw as well as the running draw. So that said you might have to increase your system capacity to reliably operate all loads. There are ups systems with line sensing circuits that if the line falls below x it switches to the internal supply system for x rated amount of time most of these- consumer rated ones- have a fairly short internal supply time.
The bearings were oiled when the furnace went through the teardown before putting it in service. It's a good point for making sure everything is up to snuff on efficiency. The exhaust motor replacement is next on my to do list this summer or sooner if winter decides to take a hike Still haven't got around to pick up a computer UPS
