Wood Boiler Operation Question

[Wood Pirate]

How will my oil boiler know not to kick on? Is this because my wood boiler will be heating the water inside the oil boiler? OR Is this through controls.

Im not sure how to word this.
Water doesnt need to constanty circulate between the wood and oil boilers correct? In other words, no matter what the actual water temperature is inside the oil boiler, the oil boiler will not kick on as long as the aquastat that is on the wood boiler recognizes that the wood boiler is heating water at or above the high limit setting of the oil boiler?

I'll tell you. I havent used this thing yet, but it sure was alot easier just throwing wood in by old woodstove

 

[Nofossil]

How will my oil boiler know not to kick on? Is this because my wood boiler will be heating the water inside the oil boiler? OR Is this through controls.

Im not sure how to word this.
Water doesnt need to constanty circulate between the wood and oil boilers correct? In other words, no matter what the actual water temperature is inside the oil boiler, the oil boiler will not kick on as long as the aquastat that is on the wood boiler recognizes that the wood boiler is heating water at or above the high limit setting of the oil boiler?

I'll tell you. I havent used this thing yet, but it sure was alot easier just throwing wood in by old woodstove

There's not enough information here to answer your question. Did you install the wood boiler yourself? In some cases, the wood boiler circulates hot water through the oil boiler. This is often done if there's a hot water coil in the oil boiler. That's not always enough to prevent the oil boiler from coming on, though. Often, the outlet temp of the wood boiler might be 170 degrees, and that might be low enough so the oil will come on at least momentarily.

Some folks use a separate thermostat for the wood boiler, and set the oil boiler thermostat a lot lower.

You can also have an aquastat on the wood boiler that disables the oil boiler whenever the wood boiler is hot.

Probably other ways I haven't thought of.

 

[Wood Pirate]

Thanks for the response. Yes I pipe it myself with some help from my old man. Its a New Yorker WC 90. According to the manufacturers directions there is not a way for water to circulate betwee both boilers unless one of the systems zone valves open. With that being said, I am assuming it will use the last method you mentioned which is the aquastat that disables the oil boiler if the wood is up to temp.

Thanks.

 

[ssupercoolss]

not to go completly of topic, but how long did it take to get your new yorker? like it?

 

[Wood Pirate]

not to go completly of topic, but how long did it take to get your new yorker? like it?

About 10 or 12 weeks. I wanted the harman but from what they told me it might not have shown up until next year.
I bought the New Yorker from a local plumbing supply. However, if you are interested in one I know there is a few guys on this site who distribute them and may have some that are on order.

 

[ssupercoolss]

i am very interested in one, because harman is giving me the shaft. i did look into the new yorker, but for some reason liked the harman better. do you know who might have one? i travel with cash. i gotta go and hit myself over the head with the hammer harman has supplied me.

 

[peakbagger]

My wood boiler circulates through my oil boiler and uses the oil boiler controls to curculate the heat, so this may not be applicable to your installation.

I installed a normally closed relay on the oil burner circuit that opens when a honeywell aquastat in the wood boiler jacket is in excess of 150 F. I also shut down the wood boiler circulator pump through the same aquastat, therefore when the wood boiler has run out of wood amd cooled down, the oil burner takes over.

 

[Wood Pirate]

i am very interested in one, because harman is giving me the shaft. i did look into the new yorker, but for some reason liked the harman better. do you know who might have one? i travel with cash. i gotta go and hit myself over the head with the hammer harman has supplied me.

Email "Supply Guy" He is a hearth.com member and had mentioned to me once before that he had a few WC90's on order. He is in Connecticut.

 

[russsmit]

It sounds like I have a similar set up...trying to work out the bugs. Here is my problem...if I turn down the set points on my oil boiler...and my wood boiler is circulating 160 degree water...then my DHW will end up being cold and the oil boiler will kick back on trying to heat the DHW.

How do I solve this issue? Install an electric Hot Water Heater?

My DHW and heat come off of the same boiler...and the domestic HW coil is very small so it doesn't have much capacity. HTe DHW comes on within a couple of minutes of turning on the hot water faucett...almost like an on demand set up.

I'd appreciate any tips or ideas on what you may have done to handle a similar situation.

 

[Nofossil]

It sounds like I have a similar set up...trying to work out the bugs. Here is my problem...if I turn down the set points on my oil boiler...and my wood boiler is circulating 160 degree water...then my DHW will end up being cold and the oil boiler will kick back on trying to heat the DHW.

How do I solve this issue? Install an electric Hot Water Heater?

My DHW and heat come off of the same boiler...and the domestic HW coil is very small so it doesn't have much capacity. HTe DHW comes on within a couple of minutes of turning on the hot water faucett...almost like an on demand set up.

I'd appreciate any tips or ideas on what you may have done to handle a similar situation.

IMHO, the simplest / cheapest solution is to install a simple electric hot water heater with a sidearm heat exchanger and a Honeywell AM-101 mixing valve (to prevent scalding).

 

[russsmit]

So connect the output of my DHW from the oil boiler into the Electric Hot Water Heater...I am thinking that I will get some preheating from the pass thru the oil boiler?

 

[Nofossil]

So connect the output of my DHW from the oil boiler into the Electric Hot Water Heater...I am thinking that I will get some preheating from the pass thru the oil boiler?

I'd be tempted to skip the in-boiler DHW coil altogether. Of course, I'd be looking at letting the oil boiler go cold, and there's some discussion about the idea that some oil boilers may not like to go cold....

Keeping 500 pounds of cast iron hot in order to keep a couple of gallons of water hot has never made sense to me, but I really don't know the risks if any in diabling your oil boiler's hot water capability.

 

[LeonMSPT]

Had an old steam system torn out and replaced with a 130K Burnham Boiler. In the basement/garage area, I had a unit heater installed for a dump zone. The wood boiler (wc90) is on its way, should be in shortly. The plumber installed the heating system with ten zones, 3500 sf apartment building, 3 units. One zone is a unit heater, another is an indirect hot water heater.

On the inlet and outlet of the new oil fired boiler, he put 2 "T's" and gate valves. Will be piped up with 1 and 1/4 steel thread pipe, with a circulator.

1. Lay a fire... normal, paper and kindling, some smaller diameter wood.
2. Light it and close the door.
3. Turn on the power switch to the wood boiler.

Fan starts, fire roars until it burns down to coals.

4. Turn the blower off, and add more wood.
5. Close the door and turn the blower back on.
6. When the water temperature in the wood boiler comes up to 160 degrees, the circulator kicks on, moving water between the oil boiler and the wood boiler.
7. Water temperature in wood boiler gets to "high limit", the fan shuts off.
8. Should water temperature in wood boiler get as high as 200 degrees, unit heater kicks on and dumps excess heat.
9. If water temperature gets back down to 160 degrees, the fan kicks back on.

As long as the water temperature in the wood boiler stays at or above 160 degrees, circulator continues to run.
Check valve prevents back flow in supply line between wood boiler and oil boiler.

Sounds like you've piped the wood boiler into one of the zones?

 

[LeonMSPT]

Most oil boilers with a tankless heater don't like being cold, then hot, then cold. The gasket eventually will leak, and need to be replaced. After a fashion, be snapping bolts off trying to change it, tighten it, stop the leaking.

When the plumber showed me the plans, it made a bunch of sense. Ran it by my father, retired from a lifetime of installing oil boilers, heating systems, and domestic plumbing, and a union pipefitter, he said, "Exactly!" Knew I had a keeper.

Working in Alaska for another week. Kind of anxious to get home and see my 17,000 dollar heating system, and see the wood/coal boiler piped up and burning.

Folks went by the house a couple weeks ago. My mother said my father almost fell over. "Must be a mile of copper tubing in here." Ten circulators, all lined up on the wall, with solenoids above, everything labelled. He told me the guy that did that system must walk around with a torpedo level in one hand most of the day. One of the best he'd ever seen and that included work he'd done.

Plumbing inspector was known to walk into a basement, take one look, and say, Leon Richard did this job? When the owner nodded or said yes, the inspector said, "We're done here.", and left.

Soon as the whole system is finished, I'll post some pictures.

 

[jebatty]

Should water temperature in wood boiler get as high as 200 degrees, unit heater kicks on and dumps excess heat.

JIC this didn't occur to you, possible boiler overheat can occur on high firing, just about up to high limit shutdown, and then power failure. The unit heater may not do much good as a dump zone in this case. Do you have a gravity zone of sufficient size that may be activated?

 

[LeonMSPT]

I've thought of that, and am considering a back up generator on the heating system. Alternatively I suppose I could hang some baseboard at shoulder level on the wall in the garage that would gravity feed. With the loop between the wood boiler and oil burner, don't think it would work to pipe the dump zone into the largest zone in the house.

Not sure how much "gravity feed" is going to occur through the system if the power goes out. A loop of radiator might be needed. Course, unless we have another ice storm like in 1997, we likely aren't going to be without power for more than an hour or so.

Thanks though, always thinking.