I have a propane fired boiler that requires a pure sine wave energy signal. Very efficient unit but worthless when I lose power. It won't fire when the house is running on my portable generator. Question is, is there an AC to AC inverter for this purpose? I have only been able to find DC to AC units for this. I want to keep this simple for my family. They have enough issues pulling out the portable and plugging it into the house when I am not home.

 

You don't invert AC to AC. However, although expensive, you could possibly install a "power conditioner" in line. Do research on it first by googling it and seeing what is out there and if it will apply to your situation.

 

Another option is to use a decent quality 12 volt DC to 120 volt AC inverter.
I use a Zantrex on my sump pump that runs on 120 volts with normal power then switches to battery in a power failure.
These units are approved for permanent wiring and would work on your furnace.
Your generator could charge the inverter battery during an extended power failure.........

I got the 1000 watt model for $150.00 on sale.

 

If you follow Greg's thoughts you can install a battery charger to the 12 volt battery and connect that to your generator. This will keep you up and running for as long as the generator is running. Depending on your boilers load you may only need to run it every so often to charge the battery. You could even charge it with solar or wind power.

So the connection line would be:

Generator----> Battery charger----> 12 volt battery----> Inverter---->Boiler

Another option would be to buy a generator that puts out a pure sine wave. I believe Honda makes one but they are about $1000

 

A good off-the-shelf option would be to get a computer uninterruptible power supply (UPS) that has automatic voltage regulation (AVR) and pure sine wave output. It will take the relatively dirty power from the line or the generator and convert it to a very clean signal for the boiler. There are UPS models that can be hardwired into the boiler circuit.

 

Thank you for your input. I have to figure out what the initial wattage is for my boiler and go from there. I want to keep this as simple as possible and would like to avoid batteries.

 

You could power the inverter from a DC power supply with no battery if the DC power supply was large enough. It might even be cheaper then a battery charger (which is basically a DC power supply) and battery.

 

How is the generator connected to the boiler? When on generator power does absolutely nothing happen when there is a "call for heat" or does the boiler initially fire and then the fire goes out within a few seconds?