My first boiler

[JohnForrest]

Hello everyone,

Trying to get off to a good start here. A neighbor gave me an old boiler (Steel King model 4800 b(h)).

I guess you would call it just a basic wood boiler, Its a 1983 year with a Triple Aquastat relay, a small blower on the back.

I have a water to air exchanger installed in my furnace , a simple PEX loop circulating the boiler water to the exchanger, a clear y strainer, and a stand pipe inside the house going up 8 feet above the loop piping.

I played around with it for a few days just to see what I wanted to do to set up the controls.

Then I discovered this site so...

Can anyone point me to some good info for a good basic design, vocabulary usefull information type spot.

I don't want to ask a bunch of questions till I know the basics.


To test what I've got, I have my furnace fan running all the time, the circulation pump running all the time. On a 20 degree day, without the blower on the back of the wood box running, half loaded with wood, it heats the water to around 100 degrees, the air coming out of the duct work is 80-82 degrees. That all gets the house a little too warm. Running that way for 8 hours it went to 75 inside the house, and I've got creosote dripping from the chimney.

So I figure I need to use the inducer blower to burn the wood hotter, keep my water warmer and control the furnace fan so I don't get the house so hot.


My worry is the 180 degree heat range written on the PEX, the 150 degree limit on my clear plastic y strainer, getting my furnace plenum to hot. It only takes 10-15 minutes to get the water from 100 to 140 turning on the fan in the back of the boiler fire box.

Thanks for looking at this and any help you might have.

Best regards,

John Forrest

 

[E Yoder]

You'll love it once the controls are right.
Normally a boiler should run around 180 F. You won't hurt the Pex or plenum at that temp.
Is this unit pressurized or an open to the atmosphere system? By standpipe I would guess you mean open?
With starting and stopping the air handler with a thermostat you should be able to control the house within 1 degree.
I don't know about that boiler in particular but in general natural drafting will cause creosote. But it needs to shut down pretty tight if you cycle it. Solenoid or damper actuator with forced draft.


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[JohnForrest]

Yes Its an outdoor wood boiler, unpressurized. When I wrote plenum I should of said my AC A coil, Agenst advice from some and taking advice from others, I installed my hot water transfer coil above my furnace between the furnace and the ac A coil. The A coil's got a bunch of plastic in it and a few people warned me I would have trouble but it was the only way to get it to fit without lowering the basement floor.

 

[E Yoder]

It'll be fine. We've done it numerous times. Just don't attempt to heat with both coils at the same time. Freon can't cool off.

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[JohnForrest]

So some corrections and additions, Not sure if this unit was intended as a pressurized boiler. It does have a pressure gauge that goes way up there but I don't intend to use a pressure system so not sure that it matters.

What I am looking for is a simple control system utilizing what I done so far and the controls already on the boiler. I would like to keep the temp a little on the lower side if possible. Also wondering if I add a big storage tank in the basement could I just let the firebox run empty to stop all the smoldering and and creosote problems. Have my furnace blower kick on when asked to, have the firebox blower kick on when needed. Is there a site that has a detailed schematic for this type of thing?

 

[E Yoder]

The simple way to do it would be to jumper the TT terminals on your aquastat. Connect your pump wiring to the C terminals. This will make the pump run all the time when water temp is above the low limit to prevent stratification and boiling. The aquastat will always run on the hi limit in this configuration. The low limit will shut the pump off if the water temp drops below the low limit set point. I would set the hi limit at 160 and low at 140 to start. Differential could be set at 10. The low limit setting will help keep you from condensing and making creosote and also help you get past that point quickly before removing heat via the pump and air handler. Cycle your air handler blower with a stat. The boiler and air handler don't need to communicate to get good heat. If you want to incorporate storage there are guys on here that have more experience than me.

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[Fred61]

If You're overheating your house with 80 degree air in 20 degree weather you have a pretty low heat load. You will probably always have creosote problems unless you add storage and batch burn. All the controls in the world will not stop the inevitable.

 

[JohnForrest]

Thanks E and Fred,

I like the super simple approach. The house is only 28x36 story and a half. I joined the tiny house movement in 1993. Ive been thinking about storage and running my burns in batches as I need them to cut back on creosote with this old burner.

My main goal is just to make the controls reliable, kind of fail safe, simple.

When I first started up the circulation loop I had an air lock somewhere and while I was down in the barn looking for tools and fittings my kid decided to help me by plugging in the firebox blower that she saw was laying there unplugged. So I at least know the boiler can handle 270 degree water in the jacket.

 

[Fred61]

270 degree water AKA steam!

 

[E Yoder]

That sounds a bit dangerous, or at least really steamy! Normally the draft fan (and damper if present) should be connected to the B terminals on your aquastat, not plugged into the wall. This allows the aquastat to shut it down on the hi limit setting. There should be some sort of a damper to prevent natural drafting or it will continue to heat up unless your load of wood is consumed.

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[Fred61]

If a wood boiler decides to go rouge and over fire there is not a damper in the world or electronic device that will stop it. That's why all these guys that install these things make an overheat dump part of the installation.

 

[leon]

Hello everyone,

Trying to get off to a good start here. A neighbor gave me an old boiler (Steel King model 4800 b(h)).

I guess you would call it just a basic wood boiler, Its a 1983 year with a Triple Aquastat relay, a small blower on the back.

I have a water to air exchanger installed in my furnace , a simple PEX loop circulating the boiler water to the exchanger, a clear y strainer, and a stand pipe inside the house going up 8 feet above the loop piping.

I played around with it for a few days just to see what I wanted to do to set up the controls.

Then I discovered this site so...

Can anyone point me to some good info for a good basic design, vocabulary usefull information type spot.

I don't want to ask a bunch of questions till I know the basics.


To test what I've got, I have my furnace fan running all the time, the circulation pump running all the time. On a 20 degree day, without the blower on the back of the wood box running, half loaded with wood, it heats the water to around 100 degrees, the air coming out of the duct work is 80-82 degrees. That all gets the house a little too warm. Running that way for 8 hours it went to 75 inside the house, and I've got creosote dripping from the chimney.

So I figure I need to use the inducer blower to burn the wood hotter, keep my water warmer and control the furnace fan so I don't get the house so hot.


My worry is the 180 degree heat range written on the PEX, the 150 degree limit on my clear plastic y strainer, getting my furnace plenum to hot. It only takes 10-15 minutes to get the water from 100 to 140 turning on the fan in the back of the boiler fire box.

Thanks for looking at this and any help you might have.

Best regards,

John Forrest

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


Please order 2 books written by Dan Holohan from Amazon or www.dansbooks.com

Dans writes from the standpoint fo being a plumbers helper, and a tech rep that also did troubleshooting on Long Island.

The first paper back is "Pumping Away" which help both the beginner and the season plumber understand the whats and wherefores of hot water heating.

The second book is "Classic Hydronics" which discusses hot water and steam heating history and the plumbing and parts used for heating systems.

Invest in the two books above and you can avoid a huge set of problems and you will have a heating system that works and works well with low temperatures.


After you read those books you will know plenty about plumbing and heating.

You can also improve your burn by filling your boiler half full of firebrick and the fire brick will hold the heat from the fire and shedd it back into the firebox slowly and you will have much less creosote to worry about as the fire bricks will let you burn hot small fires. to maintain a low water temperature that the boiler can manage and maintain.


Please do this !!

Please diagram your system as I am trying to understand what you are doing with a stand pipe for your hot water.

If you lower your water temperature your system will respond faster.

Now you can set your triple aquastat at 160 high and 130 low with a 10 degree differential and you will have plenty of hot water.
If your worried about your Pex line replace it with a high temperature high pressure braided wire washing machine hose if you are ok with soldering boiler drains into your system.

I would replace your strainer with a brass one as soon as possible and purchase a low volume single speed circulator of 12 GPM or less.

Eventually you can install a larger B+G steel storage tank in the basement as a tempering tank and use it as storage at the same time.
feeding cooler water to the circulator that moves water to your air plenum.

 

[E Yoder]

Dan Holahan is a great writer. Very informative and a hoot to read.

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[JohnForrest]

The books are exactly what I was looking for. Learning about this stuff is half the fun.
I had an interesting conversation about the extra drag created by the water coil I added inside my plenum. A tinner friend pointed out I had already added a high efficiency filter and an A coil. He suggested checking the temperature differential between return air and heated air. there's a spec on the furnace itself what that differential should be. He also suggested changing my thermostatostat setting to electric heat so there's no delay turning the fan on if the furnace should start up when my boiler system cools off as emergency heat. not sure what to really think about that.

 

[JohnForrest]

Leon,

Thanks for your info,

My stand pipe is just a t in the loop. My loop travels in and out level with the rafters in my basement. I put a t in that loop and a pipe comes up into my main floor about 6' tall. I've got a two gallon tank open at the top and its open to atmosphere. I thought that would catch air and keep the system full of water and I could see the water level change easily from the main floor. It seems to be working ok.

 

[E Yoder]

We usually aim to do no less than 80 sq. in. of coil per ton of cooling. That's with a standard 3 row water coil.
I'd watch for frost on your AC coil this summer, that's where you'll notice airflow problems first.
Also use a looser filter?
You're right, the temp rise while running the gas would tell you the airflow if you crunch some #'s, haven't seen it be a problem though. AC is much more critical.

 

[E Yoder]

You'll want to be pumping away from your standpipe as it is the reference point as to whether the circulator uses positive or negative pressure to move the water. Pushing water will protect from cavitation issues and get air out easier.
Should work fine as any unpressurized boiler would be the same thing. Ideally it would be off the top of the boiler so if it boils the steam doesn't have to push out through the lines.

 

[JohnForrest]

I have my standpipe between my coil and the circulation pump. From the pump water goes to the boiler, back into the house, through y strainer and into coil.

I have a relief valve on the boiler itself and I replaced it with a pressure/temp relief. Didn't want pressure to blow water out the top of my stand pipe only if there was a problem, it's in the house and quite a ways from the boiler. It worked really well when I overheated that first day.

I don't have any kind of damper or emergency damper yet. When we accidently left the fan on too long the fire slowed down as soon as we shut off but I want to get something added to be sure.

 

[E Yoder]

Just curious, how much water does the boiler hold? I hadn't heard of that brand before.
Sounds like your standpipe is in the right place in the loop. With a plate exchanger in the loop you could preheat all the water going into the water heater. That's how mine is done. Pump>plate exchanger>coil> boiler. Endless hot water.

 

[JohnForrest]

I'm not sure what it holds, we filled it with a hose at the bottom of the boiler intake to get out the air and watched the tank at the top of the standpipe. Ill guess it holds around 5 gallons. I plan to do just what you do with the water heater and add a big holding tank. Just kind of hooked up a temp loop to get the old boiler tested first and be sure it works for a while before I did to much to it.

That unit must not of been too popular, I cant find anything about it online or see anyone using it.

I ordered the books mentioned earlier, so I'll study up on designs a little. I appreciate all the help from everyone.

 

[E Yoder]

Yeah, that low of volume will be tricky to control. Some extra storage will really help. And a really tight automatic damper.
Enjoy!

 

[JohnForrest]

For all my fellow fire bug friends, here's a fun idea for next bonfire. Moai statue like Easter Island variety, cut out of 18" x 4' Pine log. drill hole down center and from eyes. nose, mouth. Their hard to light and get going but they are fun as they burn inside out.