Wood boiler remote piping design

Gary Hoyt

I've read "Pumping Away". I'll be connecting a closed system wood boiler located 80 feet from the house, to the house hot water baseboard system. The wood boiler holds 1000 gallons and the expansion tank is 2' x 6'.

Any books, references or ideas you can recommend on connecting a remote closed system boiler to a system and how to connect and keep the "pumping Away" concept intact, would be most appreciated. My two biggest questions at the moment are:

1. Best location for this large expansion tank (I have limited space in the house).

2. any special considerations for the water coming in from the wood boiler (the 3 - 4 gallons of water in the 80' of supply piping) will be relatively cold (below 130 degrees) when it first gets to the house. Any condensation concerns in the houses' oil boiler?

Al Letellier_9

wood boiler

Gary, I am quite surprised that you don't have that information from the boiler manufacturer. Did you say 1000 gallons in the boiler??? Wow. How big is your house? This is a job for a professional heating contractor. If the boiler builder or their rep can't help you out, maybe you've got the wrong boiler for the job.

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Jed_2

WOW!

What do you mean by a "closed system wood boiler"? Your home's system is closed, and, IS the wood boiler really a wood furnace, i.e., atmospheric outdoor wood furnace? 1,000 gal. of water content is a good bit of thermal mass. Is it pressurised? Yoweeeee! Some have HX's. I guess if you need that expansion tank, it's pressurised. Constant circulation and a Primary/Secondary arrangement will keep the SWT where you need it to be, and cycle the heat demand to the secondary (system) circs. Expansion tank location? You're on your own, but it better be in the wood boiler loop.

Jed

ALH_4

Wood

1) The wood boiler should not be circulating through the oil boiler.

2) You will need a method of switching the oil boiler off when the wood boiler is working, and vise-sersa such as a Tekmar 150. The 150 will have to sense when the wood boiler is above your desired minimum, and turn on the wood boiler circulator and turn off the oil boiler circ. You do not want any possible situation where the oil boiler is heating the water in the wood boiler.

3) If you have outdoor reset, a new primary loop will likely need to be established to receive heat from either appliance.

4) Locate the expansion tank near the suction side of the wood boiler circulation pump.

Hopefully this makes sense. I have seen some really bad wood boiler piping diagrams. You have undoubtedly spent quite a bit on the boiler. It is wise to invest a few more in the appropriate controls that will maximize your ROI.

What brand of wood boiler is this? Can you post a link?

-Andrew

Dave Belisle

wood boiler

I Always pipe a wood boiler like a extra zone of heat .
I use an aquastat with normally open , normally closed contacts

When the wood boiler comes up to temperature the circulator between the to boilers starts and it cuts the power to the oil burner. When the wood burns out and the wood boiler cools the circulator between the two boilers stops and the oil burner power is restored.

Be careful what the outdoor wood boiler manufactures call a closed or pressurized system. I have one to install that has a hard rubber with a rod sticking out of it , setting in a pipe on the top of the boiler !!

They are calling these units pressurized boilers !
I call it a rubber ball setting on top of a pipe .

I don't know what bothers me more . the fact there blowing sunshine up peoples butts, or that I didn't think of it first.

Either way I'm not impressed....

I might use a heat exchanger between my hydronic system and wood boiler if it holds that much water. That is a lot of expansion and a lot of Oxygen.

Dave in NH

Jed_2

Andrew

He didn't say anything about an oil boiler. Hence my concern about the piping and system connecton and thermal mass, and esp tank location. More info needed.

Jed

ALH_4

Oil

#2 in the original post mentions an oil boiler.

-Andrew

Jed_2

Yup, missed it

Gotta be a wood furnace. Get a Professional solid fuel Pro!

Not the seller, they don't usually know what they're talking about.

Jed

Gary Hoyt

wood boiler remote location design

Thanks to all for your input. I'm a plumbing pilgrim trying to do this job myself .... yikes. The boiler is a pressured system made by Switzer's Custom Woodburning System, Inc. in Dundee, N.Y. (607-243-8689). I see no web link. If there is one, I'll send it later.

I wasn't impressed w/ outdoor units I investigated until I saw this unit. It's a "real" boiler, designed to burn the smoke. Fire and completely burn a load of wood. Little to no Creoste and little ash. I've checked with current owners. They are impressed. Heat up the 1000 gallons (my model size .... I have 3000 sq ft to heat) and extract heat as needed. Check the water temp on occasion and start another fire when needed (you don't let unburned wood smolder in the fire box which causes creosote problems). Oil fired unit in house to kick in when you are away from the house for more than a day. I could simplify the set-up if I bought the oil gun that goes with the Switzer, but don't want to heat the 1000 gallons w/ oil (!?) I'm off the subject ....

I don't want the wood unit to freeze when i'm not around for a few days. I've initially designed in a circulator to kick in when the wood boiler temp gets low. I'm concerned though about thermal shock when that reatively low water temp reaches the oil unit in the house. I'd prefer not to have a circulator running all the time between the house and wood shed.

Anymore thoughts/advice would be appreciated.

Woodman

1000 gallons?

So does the boiler hold 1000 gallons, or are you using a 1000 gallon storage tank? The tank method is used by many mfg's usually with coils installed for the boiler water and a separate coil for the load both being "closed", with pri/sec setup. The tank water (1000 gallons) remains unpressurized to eliminate the need for a huge expansion tank. With this you can put glycol in the wood boiler loop for much less expense.

Leo

Wouldn't it be easier

Wouldn't it be easier to invest all this money into the primary system (oil boiler). A new boiler with high tech controls and indirect water heater would be a great investment and save fuel without the hassles of wood. Not to mention communities and states are looking into regulating outside wood boilers..

Leo

hot_rod

not much info

sounds a bit like a gasification boiler. But I have never seen one of that capacity. Be hard to build an efficient fire box around 1000 gallons?

Sounds a little like the high volumne Garn boilers?

Regardless, if the boiler "sees" that 1000 gallons be sure to size the expansion tank correctly. My gasification boiler is connected to a 500 gallon buffer tank and required around a 50 gallon expansion tank. Have a B&G or Wessel rep size the expansion tank.

I'd primary secondary the whole package. Never flow through an un fired boiler, either the oil or wood fired. With P/S you can build a very control friendly system.

3 way zone valves would be another option.

hot rod

Woodman

yes

Well said hot rod. Does sound like a gasification unit, "burns smoke"... What gasification boiler do you have hot rod? I've been looking at the HS Tarm, wondering if anyone has had good or bad experience running them...

hot_rod

The Tarm is

a fine unit with a very good track record. The www.wwodheat.com website of the Nichols show some nice installs. Also their pellet boiler line.

Most gasification units are Euro born. I have an EKO Vimar in my shop. I'm told they build the Viessmann gasification units, according to a factory spy

PK Pyro is another I have used, rumors tell me Buderus may have bought that company??

Atmos is another brand that I have installed.

A buffer tank is a must in my opinion.

Aqua-Therm is importing the Verner line www.verner.cz. I have their small corn/ pellet boiler in my shop waiting for an install. Very nice well enginnered product. A very smart microprocessor monitors exhaust emissions and temperature to keep it burning at peak efficienct. Also a phone dial up feature.

I saw a stainless condensing pellet boiler (prototype) at the recent ISH show. I think! Built in the USof A

hot rod

Woodman

Thanks

Thanks Hot Rod, a buffer/storage tank will definately be included. Hmm, condensing pellet boiler, maybe I should wait a little while...