Soft coal boiler help...

bbell94

Hellp all, I am new to this forum and looking for some expertise on my soft coal boiler. It is a very well made boiler that the PO of my house made in 1993. He made it very similar to a "Heather" boiler if any of you know what that is. As of right now, I have 3 honeywell strap on type snap switches mounted on the supply pipe coming out of the top of my boiler. 2 of the snap switches are for my dump zones and the other 1 controls my draft door. The problem I have sometimes is the water in the boiler itself will get significantly hotter than the water in that supply pipe coming out of the boiler. So essentially, on a warm day when the thermostats in the house aren't calling for heat, the water at the snap switches might be 160° but the water in the boiler might be 220° because the circulator pumps arent pulling water up to the snap switches. This happened to me yesterday when I was at work and at some point my pop off blew. So my question is, is there an immersion aquastat I can thread directly into the extra bung on the boiler and wire it up to run both my dump zones and my draft door?

Steamhead

Sure- any standard Honeywell aquastat should work. If you need more switch contacts, wire it to operate a suitable relay. Just get the proper well to go in that hole.

EBEBRATT-Ed

@bbell94

Depending on what you want it to do, dump zones I would think would close the contacts on a temperature rise to start the zone circulators.

The draft damper I would think you would close the damper on a temp rise. You may have to use som e relays to do all that with one control as @Steamhead mentioned

bbell94

Each zone of the house has it's own honeywell switching relay RA832A. You can kinda them in the background of the 1st picture. I'm not real familiar with wiring up aquastats. Which one would you guys recommend?

leonz

Are you burning Western Sub Bituminous Coal or Lignite? If so from which mine?? The reason I ask is you have fine powder ash like the Sub Bituminous Coal in Montana and Wyoming makes.

Is the pressure gauge on your boiler a Marsh Instruments triple gauge?

This is important!!
Are both boilers sharing the same chimney???


1. Do you have a manometer like the Dwyer Mark II manometer?
2. IS there barometric damper in the coal boiler flue pipe going to the chimney?
a. is it mounted in a horizontal flue pipe?
b. If it is mounted in the horizontal flue pipe the door weight must mounted in the left slot and pushed all the way to the left and locked.
c. if it is mounted in a vertical flue pipe the damper door weight should be mounted in the right slot and pushed all the way to the right and locked.

How often do you clean the flue pipes of fly ash??
Do you have a Tee anywhere in the flue pipes to allow you to collect the flyash as it drops out and
then allow you you to remove a plug or cap and let it drop into a bucket to collect it??

With my personal experience with wood and coal burning for 33 years in a hand fed and my current stoker I can recommend The Honeywell L8124L triple aquastat to do the job of controlling the damper door motor too.

You can set the low limit to 140 Degrees Fahrenheit and the high limit to 160 Degrees Fahrenheit.
I had plenty of heat and hot water for our needs in the 33 years I used the hand fed wood and coal boiler.

ONE BIG question; Is the combustion blower set up with a solenoid powered door to shut off the inlet air when the boiler reaches temperature? If it does not have a solenoid powered magnetic door to shut off the air inlet you need a combustion blower with a solenoid powered shutter door.

If the combustion blower is not sealed off the air on the boiler room will continue to enter the firebox through the blower.

I need to see more pictures of the boiler and the combustion blower.

If you have a barometric damper in your flue pipe I would like to see a good picture of it.

=================================================================


You need to make sure you order the conductive paste for the immersion well to increase the sensing ability of the bulb.

You will need three R845 relays for the three zones to mate with the L8124L and a reducing bushing reduced to 3/4" for the tapping in the side of the boiler. You will need pipe dope and teflon tape to seal the reducing bushing. DO NOT USE teflon tape or pipe dope on the immersion well as it will affect the immersion wells ability to sense the water temperature and transmit the heat to the probe and then to L8124L Triple aquastat.

My old hand fed used a single aquastat for the single dump zone set at 190 Degrees Fahrenheit. You just need to pick one of the zones for the single dump zone for that circulator. My coal stoker boiler uses a single aquastat for the control of the dump zone.

If you are not familiar with electrical work concerning boilers its better that you hire an electrician to do the work for you.

Do not let anyone tell you that the L8124L is no longer available, they are still made and sold.
You may have to go to www.supplyhouse.com OR www.Mcmastercarr.com or a large local plumbing supply house if you have one nearby.

DO not buy a digital triple aquastat for this boiler!!!!! You need a mechanical triple aquastat to tolerate the heat from the boiler shell.

bbell94

leonz said:

Are you burning Western Sub Bituminous Coal or Lignite? If so from which mine?? The reason I ask is you have fine powder ash like the Sub Bituminous Coal in Montana and Wyoming makes. Is the pressure gauge on your boiler a Marsh Instruments triple gauge? This is important!! Are both boilers sharing the same chimney??? 1. Do you have a manometer like the Dwyer Mark II manometer? 2. IS there barometric damper in the coal boiler flue pipe going to the chimney? a. is it mounted in a horizontal flue pipe? b. If it is mounted in the horizontal flue pipe the door weight must mounted in the left slot and pushed all the way to the left and locked. c. if it is mounted in a vertical flue pipe the damper door weight should be mounted in the right slot and pushed all the way to the right and locked. How often do you clean the flue pipes of fly ash?? Do you have a Tee anywhere in the flue pipes to allow you to collect the flyash as it drops out and then allow you you to remove a plug or cap and let it drop into a bucket to collect it?? With my personal experience with wood and coal burning for 33 years in a hand fed and my current stoker I can recommend The Honeywell L8124L triple aquastat to do the job of controlling the damper door motor too. You can set the low limit to 140 Degrees Fahrenheit and the high limit to 160 Degrees Fahrenheit. I had plenty of heat and hot water for our needs in the 33 years I used the hand fed wood and coal boiler. ONE BIG question; Is the combustion blower set up with a solenoid powered door to shut off the inlet air when the boiler reaches temperature? If it does not have a solenoid powered magnetic door to shut off the air inlet you need a combustion blower with a solenoid powered shutter door. If the combustion blower is not sealed off the air on the boiler room will continue to enter the firebox through the blower. I need to see more pictures of the boiler and the combustion blower. If you have a barometric damper in your flue pipe I would like to see a good picture of it. ================================================================= You need to make sure you order the conductive paste for the immersion well to increase the sensing ability of the bulb. You will need three R845 relays for the three zones to mate with the L8124L and a reducing bushing reduced to 3/4" for the tapping in the side of the boiler. You will need pipe dope and teflon tape to seal the reducing bushing. DO NOT USE teflon tape or pipe dope on the immersion well as it will affect the immersion wells ability to sense the water temperature and transmit the heat to the probe and then to L8124L Triple aquastat. My old hand fed used a single aquastat for the single dump zone set at 190 Degrees Fahrenheit. You just need to pick one of the zones for the single dump zone for that circulator. My coal stoker boiler uses a single aquastat for the control of the dump zone. If you are not familiar with electrical work concerning boilers its better that you hire an electrician to do the work for you. Do not let anyone tell you that the L8124L is no longer available, they are still made and sold. You may have to go to www.supplyhouse.com OR www.Mcmastercarr.com or a large local plumbing supply house if you have one nearby. DO not buy a digital triple aquastat for this boiler!!!!! You need a mechanical triple aquastat to tolerate the heat from the boiler shell.

I am from central PA. I am burning bituminous coal out of our local strip mines. We call it "C" coal.

Yes it's a marsh triple gauge. 

Yes, both the oil boiler and coal boiler share the same flue.

No manometer.

Yes the coal boiler has a baro on the horizontal flue pipe and it's set correctly.

I have a cleanout in the bottom of the flue and I clean all the ash out every fall before I fire.

I would just like to know which aquastat I need to control both my dump zones and my blower. I like to have my dump zones set at 200° and I have my blower so it kicks on at 140° and kicks off at about 170°.

Robert_25

I am not sure how your system is piped, but if you can circulate water between the two boilers continuously that would correct your problem.

You can also add an aquastat well to the port pictured.

leonz

As robert_25 stated you can create a balanced temperature zone between both boilers using a second circulator powered to run continuously like I had on my old hand fed and oil boiler that were side by side.

Your dump zone operates independently of the triple aquastat to protect the heating system in the event of an over fire to prevent a boil out by turning on the circulator to dump heat in a zone and turn it of when the boiler is cooled down.

An L8124L should be fine for what you need to do to control the boiler properly BUT If the combustion fans air inlet is not closed when the blower is turned off it will continue to let combustion air into the fire box.

Part of the problem is that you have two barometric dampers and you should only have one since you have the same flue for both heating appliances.

The boilers are not up to current NPC code as they cannot share the same flue and you should plan on having a draft inducer installed in the oil burner flue pipe to keep the oil burner flue separate.

EdTheHeaterMan

This is the Well Adaptor that you can use to install any aquastat in the plugged tapping you pictured.

https://www.supplyhouse.com/OMI-121371B-OMI-3-4-Aquastat-Well?gclid=Cj0KCQiA-OeBBhDiARIsADyBcE7izv9eDAuRZZ60VUxLjZnwQYWtHMXahVzJwOtPBwXiCTe9P-KWu38aAvBdEALw_wcB

Any of the aquastats that the others have posted will fit on that "Well Adaptor". It is available in 1/2" pipe thread and 3/4" pipe thread sizes. There are also short and long versions depending on the thickness of the boiler covering/Jacket and insulation that needs to be penetrated.

EdTheHeaterMan

Your existing controls are probably L6006C1018 or something similar
The exact same control that will fit in the "Well Adaptor" is L6006A1012


https://www.supplyhouse.com/Resideo-L6006A1012-High-or-Low-Limit-Circulator-Aquastat-100-240-DegreeF-range-5-30-DegreeF-Adj-Differential

You can also get two aquastats in one box and insert it into the one tapping well adaptor.



https://www.supplyhouse.com/Resideo-L4081B1047-High-Limit-Circulator-Aquastat-10-DegreeF-High-Limit-10-DegreeF-to-25-DegreeF-Low-Limit-Adj-Differential

This will do the job or two L6006C strap-on controls you currently have.

I hope this info helps!

Yours truly,
Mr.Ed

bbell94

EdTheHeaterMan said:

Your existing controls are probably L6006C1018 or something similar The exact same control that will fit in the "Well Adaptor" is L6006A1012 https://www.supplyhouse.com/Resideo-L6006A1012-High-or-Low-Limit-Circulator-Aquastat-100-240-DegreeF-range-5-30-DegreeF-Adj-Differential You can also get two aquastats in one box and insert it into the one tapping well adaptor. https://www.supplyhouse.com/Resideo-L4081B1047-High-Limit-Circulator-Aquastat-10-DegreeF-High-Limit-10-DegreeF-to-25-DegreeF-Low-Limit-Adj-Differential This will do the job or two L6006C strap-on controls you currently have. I hope this info helps! Yours truly, Mr.Ed

Thanks alot Mr. Ed I think that double aquastat will do what I need it to do.