Using existing controls for add on coal boiler

Hi everyone new to forum and heating systems. After spending a fortune in oil this season time to do something. I would like to install either a Harman VF3000 coal boiler or a similiar Leisure Line. Both have dealers in my area. New Hampshire seacoast. I think i can handle the plumbing. I would just hook the coal and oil boilers in series. Don't really care about the heat loss with running the hot water through the idle boiler. I want to keep things as simple as possible. The problem i'm having is understanding how to control the system. Current boiler is a Energy Kinetics System 2000. Great system, but with oil prices going up still costing me a fortune. Set up is one circulater on supply and three zone valves. Zone 2 main house, zone 1 breezeway, zone 1 DHW. I guess my question is can i use the existing controls. Can I turn down the current aquastat so the oil burner never fires. Really don't understand this though because how do i control the coal boiler water temp without wiring the thermostats to it? Seems to me I would have to keep the coal boiler at a constant 180 degrees. Bought a couple of Holohans books, Pumping Away (yet to be delivered), but still can't really find anything on controls.
Energy Kinetics won't talk to me because i'm not a dealer and the dealer down the street from me blew me off. Could have had the install job. Please help, just trying to save money.

The VF3000 and I'm sure the Leasure Line also come with controls to regulate boiler water temperature. If you can handle the plumbing I think you are home free. I run a circulator 24/7 from coal boiler to the oil boiler. Just an on/off switch for control on that. You can either just turn down the oil boiler aquastat so it doesn't run unless your coal boiler temp drops drastically or do what I did and just disconnect a wire to the burner control so it cannot fire. All your zones will still operate as they do now from the oil boiler. The only difference is you are making the hot water for 2/3 less.

I'll take a shot at this, I think the EK control (the box with the lights on it) has a switch for the burner and a switch for the system, if you turn off the burner the rest of system still works. It's been a long time since I looked at one. Jump the tt on the coal boiler and use the high and low limit for coal boiler controls. Run the pump between boilers 24/7.The tt on the oil boiler will run everything else. But I could be wrong. Good luck

crazy4coal wrote:I'll take a shot at this, I think the EK control (the box with the lights on it) has a switch for the burner and a switch for the system, if you turn off the burner the rest of system still works. It's been a long time since I looked at one. Jump the tt on the coal boiler and use the high and low limit for coal boiler controls. Run the pump between boilers 24/7.The tt on the oil boiler will run everything else. But I could be wrong. Good luck

The answers so far pretty much answer it well. Its simple really.

Yeah from the people I talked with, it sounded that easy. My friend has a leisure line and loves it. Just wanted fo find out what other people thought. Really don't want to screw my heating system up. I'll keep doing my research. Thanks for the help.

I don't think you will screw up your heating system. Also, FYI, although my vf3000 has served me well, I'd lean toward the Leasure Line boiler. You can't beat the customer service.

OK guys hate to sound ignorant, but after sleeping on it. My friends Leisure Line is his only boiler, so when it comes to what I want to do I can't really see what he did. My next question is after reading the manual for the Harman I cant find anything about the two boilers talking to each other. How does the coal boiler know when to bring the water up to temp? When the existing thermostats call for heat? Or does it just cycle between the high and low temp settings all day. Also if I have a professional do the piping what should I expect to pay. The current system is only four years old so the existing piping is pretty clean (new), not a rats nest for lack of a better term. Single return and supply feeding the three zones. Steel pipe off the boiler into the copper headers, then back into steel pipe going to the radiators. Expansion tank mounted on supply under the burner. I have the room to put the coal boiler right next to the oil boiler. I do have the digital controller on the Energy Kinetics, maybe thats why I'm so confused. Not to good with computer stuff.

The boilers do not need to talk to each other. Think of it like this. The coal boiler has it's own aquastat that will keep the water temperature at a desired temperature range. Then you have a pump that sends the hot water from the coal boiler into the return of the oil boiler. This pump runs 24/7. The only control really is a shut off switch. The water flows through the oil boiler out the supply side of the oil boiler back to the return of the coal boiler. All you zones should work just as they do now with the same controls, thermostats, etc. The only difference is the water is being made hot by the coal instead of the oil burner.

You could disable the oil burner via a switch and just let the coal boiler maintain temperature...that is the easy way. If you want to save some coal, disable the oil burner and install a DPST relay to split the zone control end switch signal to the two boilers....that way the coal boiler can sleep at 140 degrees (for example) and only run up to the high limit when there is a heat call.

Rob R. wrote:You could disable the oil burner via a switch and just let the coal boiler maintain temperature...that is the easy way. If you want to save some coal, disable the oil burner and install a DPST relay to split the zone control end switch signal to the two boilers....that way the coal boiler can sleep at 140 degrees (for example) and only run up to the high limit when there is a heat call.

Ours already come with the triple aquastat so that is how it will function. Normal low is 160 or somewhere close and the high is 180 or somewhere close. The aquastat will always maintain the low setpoint regardless of call for heat or not. Then when the TT terminals are shorted the Boiler will maintain the 180* or high set point.
So what you can do is either set your high set point of your oil boiler at 140* and the low to 120* and the coal to 180* and 160* and run the TT terminals in parallel so you have auto back up. Or you can just leave the TT wires off on the oil boiler and just have the low setpoint be the setpoint temp of the oil. And the coal unit will be primary.

Flyer5 wrote:

Rob R. wrote:You could disable the oil burner via a switch and just let the coal boiler maintain temperature...that is the easy way. If you want to save some coal, disable the oil burner and install a DPST relay to split the zone control end switch signal to the two boilers....that way the coal boiler can sleep at 140 degrees (for example) and only run up to the high limit when there is a heat call.

Ours already come with the triple aquastat so that is how it will function. Normal low is 160 or somewhere close and the high is 180 or somewhere close. The aquastat will always maintain the low setpoint regardless of call for heat or not. Then when the TT terminals are shorted the Boiler will maintain the 180* or high set point.
So what you can do is either set your high set point of your oil boiler at 140* and the low to 120* and the coal to 180* and 160* and run the TT terminals in parallel so you have auto back up. Or you can just leave the TT wires off on the oil boiler and just have the low setpoint be the setpoint temp of the oil. And the coal unit will be primary.

Question. . Would coal boiler circular still run 24- 7

Not if you drive it off C1/C2 on the coal boiler triple aquastat.

Rob R. wrote:Not if you drive it off C1/C2 on the coal boiler triple aquastat.

Now this create more questions. So how would you get coal boiler to circulate when oil boiler temps drop? And if you remove tt from oil boiler aquastat like mention, how would oil boiler know there's a call for heat for its zone

OK guys right when I thought I could handle this I ran into a new problem. DUMP ZONE! The wires on the Harman look like their just straight 120 volt, that the controller turns on and off. I can't put 120 into a zone valve and I really don't want to pipe a seperate loop with circulater. I wish their was just a signal wire that i could piggy back on one of my valves. I read in another post this is a easy remedy, but just don't see how from reading the Harman manual (not very informative) and the wires available. Also the second circulater between the boilers do you just wire that so it plugs into a wall outlet or can I run it off the coal boiler. I would probably keep it on 24/7. Should I decide not to do this would the dealer be able to recommend installers. Thanks for the help.

In most cases, if your expansion tank is properly sized, you should never need a dump zone. In 10 years, I've never needed one. Yes the Harman dump zone control puts out 120 volt. Someone smarter than me can tell yoou if there is a relay and or transformer that can take this and turn it into your low voltage that you would need for your present system.

I see you are a new member. You didn't fill out your profile so for all we know you might live in Mongolia. IF you are closer to NEPA, I would seriously consider the Leasure Line boiler. The owners of that company are active participants on this forum, are both standup guys and provide a level of customer service that is superior by far to any other coal boiler company. That is no BS! Harman on the other hand will many times not even respond. That is also no BS!