coal boiler with oil option

I am looking at getting the Harman VF3000 coal stoker boiler with the oil burner option. How does the oil option work exactly work? When coal is needed and it is not there does the oil start to work to supplement? Does anyone have this model and do you like it?

Usually the oil option is not very efficient at heating water. The design of a coal heat exchanger is different from a heat exchanger in an oil boiler.

The best way to have a backup boiler is to leave the existing boiler in place, and install the coal burner in parallel or series. With the proper wiring of the controls, when the coal boiler no longer keeps the water hot, the oil boiler will take over.

Greg L

I am building a house so I am looking for this to be my heating source.

With a little shopping and primary/secondary loop pumping - you will have less invested in two boilers and a FAR better arrangement for efficient operation and fault tolerance. With two appliances - you can always valve one out of the system for major service, and still stay warm. Plus you can under size the oil boiler a bit and gain efficiency in mild weather when you don't wish to fire up the solid fuel appliance. Consider adding a tank for thermal mass storage as long as you starting from scratch. That too can level out the load run time and decrease number of boiler cold starts, maybe add solar for summer domestic hot water production.

I think you'd be surprised how cheap oil boilers really cost. Check a plumbing supply house, they are cheap.

e.alleg wrote:I think you'd be surprised how cheap oil boilers really cost. Check a plumbing supply house, they are cheap.

your backup could even be with a takeless propane or oil hotwater heater.

while my vf has only been running for a little more than a month, i dont see it going out.

The VF3K is very reliable. Mine has only failed once in 4 years and that's because I forgot to put coal in the hopper.
If you are financing the home as most of us do, the bank will not accept just a VF3K as primary heat. Add the oil burner option and I think you'd be ok. You would only need it if you were going away during the winter. Otherwise the coal will do the job.