Caleffi design wiring controls

cutter

I am wanting to re-pipe my two boilers and I thought of using this Caleffi design. What I thought would work is have an aquastat (Honeywell L6006A 1145) on the wood boiler that would turn the pump on when the water in the boiler reached say 150 degrees. That pump would continue to run as long as the water in the wood boiler was 150 degrees or above. The wood boiler would have another aquastat in it so if the boiler reached say 200 degrees it would open a zone valve and turn on a pump on the load side of the Hydraulic separator until the temperature i the wood boiler dropped to 180 degrees.

The conventional boiler I am sort of puzzled about. I was thinking an aquastat on the supply side of the hydraulic separator would send power to the conventional boiler when water on the supply side was below say 160 degrees. The conventional boiler would fire and circulate water through the headers and when the boiler high limit was reached the conventional boilers would stop firing. Now a zone would call for heat and a pump on the load side would come on and take the hot water from the supply side of the headers, when the water temperature would drop below 160 degrees the zone pump would shut off. The conventional boiler will not fire because the water in that boiler is above the low limit.

I see two possible solutions, move the high and low limit boiler controls to the supply side of the manifold, or have the pump on the conventional boiler run all the time there is power to that boiler.

Am I not seeing something, or is there a better way?

njtommy

Is your wood burning boiler pressurized?

Why not just add a storage tank? You can get one with two aqua stat wells and if the tank drops below temp you can switch over to your secondary boiler.

hot_rod

Many of the wood boilers have a pump relay inside the control, sometimes a simple snap switch on top the boiler operates that.

And you are looking to active a high temperature dump for the wood boiler?

Also operate the back up boiler on temperature drop?

Another control option is one of the solar differential type controls, The i solar is one example.

Function one is differential, when the wood boiler is warmer than the load, it kicks on. Set the low limit to 140F, for a simple return protection feature.

Function 2 could be the setpoint to activate dump, 200- 185 for example.
Function 3 would fire back up on a differential also. if the loop downstream from the sep drops, it fires the backup boiler call, boiler pump wired from the boiler.

There are wiring schematics in Idronics 10 that are fairly typical, it may've more parts than yours, but logic is the same.

The I-solar BX has 4 outputs, 3 are triac for VS operation of the pumps if you want, all the sensors included , nice display, some basic data logging, etc.

Or you can build it with off the shelf relays, transformers, setpoint controls, etc.
If you do, go with digital setpoint controls like the Ranco, Dwyer, HW or Johnson Controls, more function and features compared to a simple cap. tube type aqua stat.

Idronics 14 has some good basic wiring help. It shows a wood boiler wiring with heat dump but it is for power outage dump with a normal open ZV


http://www.caleffi.com/sites/default/files/file/01273_us.pdf

cutter

njtommy said:

Is your wood burning boiler pressurized?



Why not just add a storage tank? You can get one with two aqua stat wells and if the tank drops below temp you can switch over to your secondary boiler.

Yes my boiler is pressurized. I want to plumb the two boilers together like what is in the picture. The picture is a wood pellet boiler mine is a Buderus wood or coal boiler.. I do not have room in my boiler room for a buffer tank. I would put in a tank if I had the room.

hot_rod

The key with wood fired is the return temperature. Below 140 and you get some nasty, and potentially dangerous creosote build up.

Protectiont can be done, poorly by banging the pump on and off. I like the mixing valve approach as it keeps flow across the HX consistent. It is the most cost effective, accurate way to protect them.

cutter

hot rod said:

The key with wood fired is the return temperature. Below 140 and you get some nasty, and potentially dangerous creosote build up.

Protectiont can be done, poorly by banging the pump on and off. I like the mixing valve approach as it keeps flow across the HX consistent. It is the most cost effective, accurate way to protect them.

Hot Rod, I am planning on plumbing the two boilers as in the picture posted from Caleffi journal #10 page 29. I was planning on using the thermobloc mixing and circulation pump on the wood boiler, and califfe's ThermoMix boiler protection valve on the oil boiler.

What I would like to know is what is Caleffi's idea or suggestion for wiring the two boilers that is in Caleffi's drawing in their trade journal. I posted my idea above, there has to be a better way. I am most likely not seeing something.

cutter

hot rod said:

Many of the wood boilers have a pump relay inside the control, sometimes a simple snap switch on top the boiler operates that.

And you are looking to active a high temperature dump for the wood boiler?

Also operate the back up boiler on temperature drop?

Another control option is one of the solar differential type controls, The i solar is one example.

Function one is differential, when the wood boiler is warmer than the load, it kicks on. Set the low limit to 140F, for a simple return protection feature.

Function 2 could be the setpoint to activate dump, 200- 185 for example.
Function 3 would fire back up on a differential also. if the loop downstream from the sep drops, it fires the backup boiler call, boiler pump wired from the boiler.

There are wiring schematics in Idronics 10 that are fairly typical, it may've more parts than yours, but logic is the same.

The I-solar BX has 4 outputs, 3 are triac for VS operation of the pumps if you want, all the sensors included , nice display, some basic data logging, etc.

Or you can build it with off the shelf relays, transformers, setpoint controls, etc.
If you do, go with digital setpoint controls like the Ranco, Dwyer, HW or Johnson Controls, more function and features compared to a simple cap. tube type aqua stat.

Idronics 14 has some good basic wiring help. It shows a wood boiler wiring with heat dump but it is for power outage dump with a normal open ZV


http://www.caleffi.com/sites/default/files/file/01273_us.pdf

Hot Rod, I did not see this post of yours before I replied to your second post . I have looked through both journals, 10 and 14. Journal 10 has nothing that I can see that would put me on track to wire what I want to build. Journal 14 talks about different controls. But does not show a wire diagram any where close that would apply to what I would like to build. From what I can see.

I am a welder, mechanical person. Electrics are not my strong point but I can follow directions.

hot_rod

Your idea for the wood boiler would work , there are Honeywell dual controls that could do the on/ off for the pump, and a high limit, Timmie may know the part number. Many of the US built wood boilers use those dual controls. I know the Royall brand out of MN uses them. They need to go into a well in the boiler or close to the boiler piping connection.

You will also need to run the pump(s) on the system side of the sep to dump any excess heat, from the wood fired, so that pump would need to enable on an overheat condition also.

The second boiler should only fire, and it's pump run on a heat call and low temperature condition. So enable the contacts on that from the relay box that controls the zone valves or pump(s), I'm not not sure how you are running the system side of the sep?.
That call could be locked out if a sensor in the wood boiler still has enough temperature.

What I was trying to show is how one control could do all that without you sourcing and wiring all the separate components. Unless you have some control wiring and control logic experience, it can be daunting task to make all this happen.

Another option is to have Kurt SWEI build you a PLC control. Those are custom built to each application and specific to your needs. The entire system controls from one box.

So it comes down to your comfort and expertise to wire it all up.

My suggestion for these fairly complicated control logics it to write it all down, what happens when, who has priority, can both run together, safety dump under what condition, etc.

Then draw a ladder diagram like we show in Idronics with the components you want to use. It is impossible for us to show a wiring schematic for every possible condition, they are all specific to what you need and want. Guys, or gals, with control wiring can tak any of the basic schematics we show and add the additional functions and interfaces.

If you need to find someone local to help, I found guys that do industrial or commercial electrical work and troubleshooting have better control building skills, or a good HVAC/ Refrigeration contractor.

Another suggestion with wood heat, start the fire slowly, they need to be fired to the load, it is a very interactive hobby without any buffer. No reason to depend on a dump to regulate the output of the boiler, the load may not always be able to keep up with a full fire on a mild day. Wood fired boilers do not start or stop on a dime, and long hot burns will give you the best bang for you wood. It could take an entire season to learn the personality of that system, be patient.

cutter

hot rod said:

Your idea for the wood boiler would work , there are Honeywell dual controls that could do the on/ off for the pump, and a high limit, Timmie may know the part number. Many of the US built wood boilers use those dual controls. I know the Royall brand out of MN uses them. They need to go into a well in the boiler or close to the boiler piping connection.

You will also need to run the pump(s) on the system side of the sep to dump any excess heat, from the wood fired, so that pump would need to enable on an overheat condition also.

The second boiler should only fire, and it's pump run on a heat call and low temperature condition. So enable the contacts on that from the relay box that controls the zone valves or pump(s), I'm not not sure how you are running the system side of the sep?.
That call could be locked out if a sensor in the wood boiler still has enough temperature.

What I was trying to show is how one control could do all that without you sourcing and wiring all the separate components. Unless you have some control wiring and control logic experience, it can be daunting task to make all this happen.

Another option is to have Kurt SWEI build you a PLC control. Those are custom built to each application and specific to your needs. The entire system controls from one box.

So it comes down to your comfort and expertise to wire it all up.

My suggestion for these fairly complicated control logics it to write it all down, what happens when, who has priority, can both run together, safety dump under what condition, etc.

Then draw a ladder diagram like we show in Idronics with the components you want to use. It is impossible for us to show a wiring schematic for every possible condition, they are all specific to what you need and want. Guys, or gals, with control wiring can tak any of the basic schematics we show and add the additional functions and interfaces.

If you need to find someone local to help, I found guys that do industrial or commercial electrical work and troubleshooting have better control building skills, or a good HVAC/ Refrigeration contractor.

Another suggestion with wood heat, start the fire slowly, they need to be fired to the load, it is a very interactive hobby without any buffer. No reason to depend on a dump to regulate the output of the boiler, the load may not always be able to keep up with a full fire on a mild day. Wood fired boilers do not start or stop on a dime, and long hot burns will give you the best bang for you wood. It could take an entire season to learn the personality of that system, be patient.

Hot Rod
I have a little wiring experience when it is done in the KISS method or style. My thought on wiring in the wood boiler would be pretty simple. Use a Honeywell L6006A 1145 aquastat in a 1/2 inch port on top of the wood boiler. 110 volts to the R terminal in the aquastat. Wire from the aquastat W terminal to the circulating pump. Set the aquastat at 140 degrees and at temperature rise to 140 degrees the circulating pump runs as long as the boiler water is kept above 140.

For an overheat condition occurrence another Honeywell L6006A 1145 aquastat could be put is the second 1/2 port on top of the boiler. That aquastat could be set at 190 or so with a 10 degree temperature drop to open the circuit. This aquastat could be wired to the largest zone in the house as a second thermostat for that zone. That is what I have used in the past as a dump method.

To run the circulating pump on the sub manifold my thought there was to Have another Honeywell L6006A aquastat put in the manifold on the supply side of the separator. On temperature rise to 140 or 150 degrees that aquastat would send 110 volts to a transformer that would send power to the thermostats. The aquastat also sends 110 volts to terminal 1 in a RA89A Honeywell relay. On a zone call for heat the 4 wire zone valves would send a signal (was told it shorts out the TT terminals) to the TT terminals on the RA89A relay which would send 110 volts from terminal 4 in the relay to the circulating pump.

To wire Taco zone pumps on the other 3 zones I would just need to go from the same aquastat as from above to a junction box and from there to each pump with 110. Wire in a thermostat to the thermostat or aquastat terminals. And I think they will work. I have never done Taco pumps before.

That is how I think or feel the wood boiler and the load side of the system could be wired. I understand what I wrote but if you need to be a mind reader to understand it, I can send a drawing.Sometimes when I say something it is clear to me but not to the person listening.

The conventional boiler is an oil fired Burnham VP 3W. It is an older boiler that has seen little use in its life. I bought it used from a guy that converted to an electric boiler. How long he used it I do not know. I have only used it 2 heating seasons since January of 1987. This boiler has a Type R8182E Honeywell Aquastat relay on it.

An L6006A aquastat could send 110 volts to the oil boiler when the manifold drops to a 140 degree or so temperature.
Another L6006A aquastat in the supply side of the manifold wired to open at 180 degrees could short out the TT terminals on the boiler aquastat and fire that boiler, and keep the supply side at 180 degrees. At 180 degrees the aquastat would open and the oil boiler circulating pump would shut off.

The only problem I see is the circulating pump will come on as soon as the boiler fires and move warm and cold water out and in the boiler. If the pump could be told not to come on until the boiler water temperature was at 140 degrees that would be I deal.
I am thinking or feel that the new boilers that require a boiler protection valve has or may have a boiler relay that does not turn on the pump until the boiler water temperature reaches 140 degrees. If they do and if that control could be put on my oil boiler this system would.

I can not build this system until I knowif it will work. So if you or anyone else can add suggestions or corrections or are willing to share your skills and experience I would appreciate it.

The picture is what I plan on building if this works. There will be a few temperature gauges installed that is not shown also the fill and expansion tank and a few changes in the design, But this is basically it.

cutter

Hot Rod, I forgot a couple of things. I have asked locally for help with this system and no one wanted to touch it unless they could do all of it from start to finish.

For the manifold I was planning on using black steel pipe with steel caps welded on the ends and reducing couplings welded to the other ends and holes drilled and weld lets welded on for supply and return zones and any other ports needed..

I have been firing with wood since 1987 except for 2 years so I do have a little experience in knowing how much or little wood to add to a fire. But misjudging in easy to do.

The electrical engineers at Caleffi I feel should be able to cone up with a couple of suggestions on how to wire up that conventional boiler. There can't be that many different ways to do this. and if there is give a couple of suggestions with schematics. With the KISS rule in mind. Keep it simple

SWEI

Something like http://www.matco-norca.com/filesDownload.cfm?dl=Boiler Header Manifolds.pdf would save a bit of time. There's a company called Earthlee several have here have used that will make custom versions in pretty much any config you can imagine.

cutter

SWEI, thanks for the suggestion, I would rather do it myself though. Welding is my expertise, Not hot water heating design or electrical design. That is why I was wanting a little help after this design was suggested on this site. . I think I have the electrical figured out, might be a little crude though.

cutter

Hot Rod, I think I have figured out the conventional boiler wiring. When the TT terminals are shorted out and the burner fires and the circulating pump comes on. The idea is to put another Honeywell L6006A aquastat in the boiler next to the boiler supply. The piping that comes out of that port I will not need anymore. the wiring from the boiler control that turns on the pump I will wire to the aquastat to close at 140 degrees, that will complete the circuit and the pump will turn on. It will open when the temperature is below 140 degrees and not let the pump run. Anyone see any flaws in my idea, or want to chime in?

Ironman

Here's a very simple method that I've used for years to connect wood boilers to conventional. I removed the plate heat exchanger from the diagram because your wood boiler is pressurised.

The ETC is an electronic temp control that you can get from Johnson (A419) Ranco (ETC 11000) or Tekmar.
Wire it to select either the wood or the conventional boiler. Set it to 160 - 170*. When the wood boiler reaches that temp, it takes over. When it drops about 15*, the conventional takes over.
You really need some buffer to make it work right. Could you fit an 80 gal tank in there? Most are 32" or less in diameter.

Ironman

Diagram

cutter

Ironman said:

Here's a very simple method that I've used for years to connect wood boilers to conventional. I removed the plate heat exchanger from the diagram because your wood boiler is pressurised.



The ETC is an electronic temp control that you can get from Johnson (A419) Ranco (ETC 11000) or Tekmar.

Wire it to select either the wood or the conventional boiler. Set it to 160 - 170*. When the wood boiler reaches that temp, it takes over. When it drops about 15*, the conventional takes over.

You really need some buffer to make it work right. Could you fit an 80 gal tank in there? Most are 32" or less in diameter.

Ironman, the two controls you mention looks like the electronic version of the Honeywell L6006A that I am currently using. The L6006A that switches the most I think might be getting worn out. It is set to switch at 140 but the first switch after a fire is built in the morning is at around 155. the next time it switches it will switch at 140 degrees and continue to switch at 140 until the system reaches 140 and above.
The electronic ones you suggested I would say is more precise in their switching. They either work or they don't. The Ranco or Johnson look like they would work in the over heat zone. And possibly two of them would work in the circuit to turn the oil boiler circulating pump on and off at the correct temperature.
As for room for a buffer tank, there is not any room. Thanks for telling me of the Ranco and Johnson controls.

A year ago I had a plumbing design similar to yours that I posted on here to see what members thought of it. One member suggested a different design, picture one. That is what I am trying to build if I can get the electrical figured out A couple of posts up to Hot Rod is the system plumbing design that I came up with. Picture two is what I currently have that is not working. the zone valves are shot. and rather than replace the zone valves I wanted to build another header to supply two more zones and also the unit heater that I never plumbed in years ago. The header is what is a couple of posts up to Hot Rod. That would be the supply side of this system and where the boilers supply's connect to the header.

Ironman

The electronic ones have double throw contacts (NO & NC), the L6006A may only be single throw, though it's availed in double throw. The point being that with double throw, the ETC would hold the wood boiler's pump off until it reached 160* and run the conventional below that. When it gets to 160*, then the wood boiler takes over and the conventional is held off.

If you have an oil fired boiler:
1. Take the Hot burner wire off of the L8148 aquastat and run it to the NC contact in the ETC.
2. Run a wire from the burner terminal where you just disconnected the one above to the "C" terminal on the ETC.
3. Run a wire from the "NO" terminal in the ETC to the hot (L1) on the circ.
4. Also run a neutral to the circ.
5. You'll need to use a LINE voltage ETC for this application and you'll also need to supply a hot and a neutral to its 120v terminals to feed the logic.

If you have a gas boiler:
1. Use a 24v ETC and follow the same steps as above, except there will be no line voltage to the ETC.
2. You'll need a relay to switch on 120v to the pump. Use its "NO" contacts.
3. The "NO" contacts of the ETC will connect to the coil or "TT" terminals of the pump relay.

Set the ETC to the COOLING mode and set it to 160*. This way, if the ETC bites the dust, your conventional boiler will still operate.

Ironman

How about your present water heater? It could be replaced with an indirect that would act as a buffer and supply your domestic. You would need a mixing valve to temper the domestic side, but it should fit right in where your present water heater is.

cutter

Ironman, I am guessing the thermostat or thermostats in your system are wired in to the conventional boiler control. The boilers in your drawing are piped in a series so if the wood boiler is fired that water goes through the conventional boiler and that boilers controls should be opening and closing zone valves and turning on pumps. The system that Caleffi suggests is piped in parallel. that is the system I have posted that I would like to install. With parallel piping the boiler not being needed or used would be cold unless it is fired. Those boilers supply water to the header and that water returns to the boiler unless a zone calls for heat.

I tried to explain an electrical system that I thought would work or could work in an earlier post to Hot Rod. I know a picture is worth a thousand words and what I was trying to explain maybe could not be understood. I can make a drawing if you are willing to look at it and if needed make suggestions.

The two ETC's you suggested I am guessing open and close on temperature rise and decline and do not need current to pass through to work. They just need current to make the logic part work??? So an ETC could be used to short out the TT terminals on a boiler control ???? What is the longevity or mortality rate of the ranco or johnson ETC ?

Below is Caleffi's idea of connecting a wood fired boiler and a conventional boiler.

COMBINING A WOOD -FIRED BOILER
WITH AN AUXILIARY BOILER
There are several ways to connect a wood-fired boiler
with an auxiliary boiler. The usual intent is for the
wood-fired boiler to handle the heating load until its
output decreases due to fuel depletion. At that point,
the conventional boiler turns on to supplement and
eventually take over for the wood-fired boiler.
One seemingly simple method is to connect the boilers
in series, as shown in Figure 6-11. Series piping requires
system water to flow through both boilers, even if one
of them is not operating. Air currents moving through
and around the unfired boiler can absorb heat from this
water and carry it up the Chimney. Piping the boilers in
series also increases the head loss against which the
circulator must operate. Although the head loss of most
wood-fired boilers as well as conventional boilers is
small, this is not the case for some current-generation
mod/con boilers. Series piping also precludes use of
proper boiler protection. Because of these limitations,
series piping is not recommended.
Some pellet-fired boilers can maintain reasonable control
over the rate of fuel combustion and may not require
buffer tanks. In such a case, the pellet-fired boiler and
an auxiliary boiler can be piped as shown in Figure 6-14.
The pellet-fired boiler is equipped with a ThermoBloc
protection/circulation unit. The "conventional" auxiliary
boiler (e.g., one not intended to operate with sustained
flue gas condensation) is equipped with a thermostatic
boiler protection valve. The boilers are piped in parallel
to a common set of headers that connect to a hydraulic
separator. The latter device isolates the boiler circulators
from any circulators on the load side of the system.
It also provides high-efficiency air separation and dirt
separation for the system. A detailed discussion of
hydraulic separators is given in idronics #1 .
Each boiler is equipped with a check valve that prevents
reverse flow of heated water through an inactive boiler.
The check valve on the pellet-fired boiler should only
be a "swing check" valve with very low forward opening
resistance. This, in combination with the internal check
mechanism in the ThermoBloc mixing device, allows for
thermosyphon flow through the pellet-fired boiler during
a power failure.

Ironman

One ETC is all that's needed. It switches the output from the boilers aquastat to choose either the burner or the circ pump on the wood boiler. You don't do anything with "TT" on the aquastat.
I purposely leave both boilers in the circuit when the wood boiler gets hot to provide more mass and a better burn. The longer the burn time, the cleaner and more efficient it is. I don't think you're realizing how important mass (buffer) is with a wood boiler, especially a natural draft one. That's why you should also look at the possibility of the indirect tank.

P.S.
For safety, a second aquastat should be used to provide a dump zone should the wood boiler overheat. Set it to 210*. It could be wired in parallel with conventional boilers pump output to bring the system circ on.

cutter

Ironman, The indirect water heater you suggest looks like it only supply's domestic hot water. I am not sure I have enough wood to heat my domestic water and heat the house. I have an indoor supply of about nine cords of 4'x4'x8' wood. some of the wood is good, some may be a little junky and some may be low BtU stuff. A year or two ago i had a cold winter and at the end of heating season I only had 1/2 of a cord left. With a milder winter I can have three cords or a little more left at end of winter. So I am sort of on the fence about a indirect water heater.

As far as the dump zone goes I do have a dump zone wired in to the system that is no longer working. I do plan on wiring another into this new system. Currently I do not need one because the pump runs continuous if the boiler is above 140 degrees . the entire house just's gets a little hotter then.

I do have an oil boiler but do not have the control you suggest. The one I have is a Honeywell R8182E, I assume they both work in the same manner though. Would you be willing to explain to me how this control works. I can tell you how I though or think this control works, But boiler controls is not in my skill set. When the boiler is turned on the gun fires if the water temperature in the boiler is below the low limit, and continues to fire until the high limit is satisfied. The circulating pump will only run if a zone calls for heat. The thermostat is wired with 24 volts going through it when the zone wants heat. the 24 volts go to the zone valve and opens the zone valve, the zone valve then creates a short that is sent to the TT terminals in the R8182E relay, which in turn, turns on the circulating pump. When the zone is satisfied the thermostat closes, then the zone valve closes, and the TT terminals are no longer shorted out and the pump stops. If you are willing tell me if I made a mistake and what really happens. Thanks

Ironman

Does your boiler have a tankless coil that's heating your domestic?
Some pics would really help.

cutter

Ironman, The oil Boiler is a Burnham VP 3W and does not have a tankless coil. The coal or wood boiler is a Buderus . The pictures posted shows how little room I have in the mechanical room or boiler room. One picture looks west and shows the electric water heater which has enough room between it and the wood boiler to service the water softener. The other picture looks east and shows the oil boiler fairly close to the chimney. The other picture just shows the frontal view of the oil boiler that currently does not have the circulating pump wired up. That boiler has not been fired in the last 10 years. In the previous 20 years it has only been fired two years, except for an occasional two weeks here and there. The oil boiler has always had hot water in it though all those years. Before I bought it I think it was only used for a few years. There are a couple of pictures in above posts of what I was wanting to build.
I have added two zones to the house with a little addition so the current piping arrangement will not work. I would also like to modernize the system and put in things that I did not know I needed 30 years ago.

hot_rod

Your first drawing of the separator will work fine.

I don't like series boilers as you don't want the oil fired boiler heating the off cycle wood boiler. A %, maybe a large % of that oil fired energy goes up the flue of the wood boiler.

Unless there is a tankless coil involved, I prefer parallel as you show.

It's rare to find a piping schematic of a wood boiler without some sort of buffer, but the wiring logic is the same.

The control logic really depends on how you want to operate the system.

If you plan on keeping the wood boiler hot and fired, then the thermostats just call on the zone pumps. The wood boiler does not have means to start itself, so YOU become the start call for heat

The oil fired could be brought on via a control like Bob mentioned, when the wood boiler drops below say 140F, the control energized TT on the oil boiler. That fires the oil boiler, drops power to the wood boiler pump, so it's an either or logic, only one boiler at at a time is pumping into the sep.

If you have all low mass heat emitters, no buffer tank, the wood boiler return protection is not as critical, but it still keeps the boiler running hot and less chance for creasote.

Idronics 16 does give you an excellent overview on how controls work, interface, and are wired. It shows and explains how a DT "double throw" relay works and how a control with a C, N.O. and N.C. "normally open and normally closed" contacts work.



http://www.caleffi.com/sites/default/files/coll_attach_file/idronics_16_na_0.pdf

Be sure to use those flue cleaning brushes often with that wood burner. I believe it is a non-gasification type and depending on the wood you burn, and how hot you run it, the flue needs constant attention.
Dry, hard wood, long hot burns are best for cordwood burner, that will take some learning and attention especially without a buffer tank.

Wood burning is a very interactive hobby.

Ironman

Your boiler's aquastat (L8182E) has the burner's primary control incorperated in it. That means that you CAN'T break the burner wire through the ETC. You would have to break one of the "TT" wires using a relay controlled by the ETC or L6006. The relay could select the wood boiler pump from a second set of contacts on it. In other words, you would need a double pole, double throw relay. "TT" would go through the "C" and "NC contacts on one pole and the wood boiler pump would wire through the " C" and "NO" contacts on the OTHER pole.
Hotrod is of course correct that you'll burn some more wood if you keep the oil boiler in series with the wood.

cutter

Ironman, If I understand your idea correctly I would have a relay on the wood boiler double pole, double throw. If power was on to the heating system. Meaning the oil boiler had 110 volts to it at all times, and wood boiler was not lit off the oil boiler TT terminals would be shorted out and the oil boiler would fire and circulate hot water through the manifold. when the manifold gets hot, 180 degrees, the high limit shuts off the burner and the circulating pump continues to run circulating the hot water through the manifold. Even if no zone is calling for heat. And when the wood boiler gets up to temperature the wood boiler pump receives 110 volts and comes on and circulates water through the manifold. And the oil boiler TT terminals are no longer shorted out and the oil boiler circulating pump shuts down until someone forgets to stoke the wood boiler. But the Oil boiler stays hot because it has 110 volts to it at all times and the high and low limit shuts the gun off and on???????????

Bob, the post of mine above the posted pictures one of my boiler room I explained how I think my oil boiler controls work. If I do have that right would you tell me. And if not would you tell me what really happens. I am not a controls person, I have picked up bits and pieces here and there and put them together, that is why I think the control works the way I explained. And why I think your idea works like I explained. Thanks Bob