I guessed this to be a simple thing, but what is the correct way to hook the outdoor wood furnace to a regular pressurized boiler? I am assuming that the OWB is hooked to a plate heat exchanger and the boiler gets its BTU's that way. But I told my friend who is going this route that I really didn't know. How do you use a pressurized system with an OWB?
OWB to Existing inside boiler
- Thread starter abohac
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ktm250rider
ArboristSite Operative
Yup, plate heat exchanger. Well, unless your my neighbor. He just hooked his up inline. We'll see how it works this winter.
tanker
ArboristSite Operative
going on year 4 with mine plumb'ed in direct to the Welles-Mc-Clain boiler in the basement and could'nt be happier with it and can have the house boiler up and operating in about 5 minutes if I so desire by shutting two valves off and opening one turning it back into a pressurised system again or I could let it fite up and heat the house and keep the water in the c.b. hot also.
HUSKYMAN
Addicted to ArboristSite
Its very easy, just put the plate exchanger inline with the home plumbing for the registers. Then when your thermostat turns on the pump for the in house boiler, it pushes the water through the exchanger and heats the house. You never even notice a difference in the way the home is heated.
I have the pilot shut right off on my Weil-McClain boiler, but as said above I can have it running within two minutes if I need it to.
I have the pilot shut right off on my Weil-McClain boiler, but as said above I can have it running within two minutes if I need it to.
Scootermsp
ArboristSite Guru
Plate exchager
It is very important that the exchanger is hooked up so each side is COUNTERFLOW. That means the OWB hot is on the opposite end of the exchanger as the incoming boiler water.
It is very important that the exchanger is hooked up so each side is COUNTERFLOW. That means the OWB hot is on the opposite end of the exchanger as the incoming boiler water.
Yep I knew that (counter flow) but hooking it up to a plate exchanger is what I didn't know.
So really the only pump he needs is his circulation pump on the back of his stove to keep OWB boiler moving through his plate exchanger right? The inside boiler has its own circulation system, correct? He has an old farm house that has old windows and a poor insulation system. I told him go as big as he could. I am assuming he needs another exchanger for his potable water. Can his exiting water from the first exchanger go right into the potable exchanger and then back to the stove?
So really you are just using the inside boiler as a water transportation system. No longer pressurized. Doing it that way don't you always have hot water circulating around the house? Doesn't that get to warm sometimes?
itn
ArboristSite Operative
i've had mine plumbed direct for 5 years and haven't had any problems. wells -mclain inside boiler also. i've got mine hooked in with a control valve. all i do is turn the thermostat on and when my house boiler thermostat calls for heat, my house boiler pump kicks on, which also opens the control valve and i have hot water from my central boiler pumping thru my pipes. when the house boiler pump shuts off the control valve closes and it goes back to bypass.
Scootermsp
ArboristSite Guru
If you use a plate exchanger you also need a circulator pump for the loop between the exchanger and your weil-mclain boiler. It also needs to PUSH the water through, NOT pull. So make sure it's on the inlet side of the exchanger.
tanker
ArboristSite Operative
I just use the boiler for transfer,works just like using plate exchanger,the pump on the outside boiler circulates through the boiler in the basement 24/7,when one of my zone valves calls for heat,the circulating pump on the house boiler kicks in and moves it to wherever needed in the house.Also,they recomend going through the heat exchanger( in my case a sidearm instead of a plate exchanger) before going to your furnace/boiler. My c.b. dealer recomends the sidearm and direct hookup if you have any trouble at all with hard water.I know of a couple of people that have plugged the plate type with calcium deposits. Works great,have a 140deg aquastat on the house boiler to kick in as backup,will keep some heat transfer to the c.b. if wood fire goes down(you know ,in case of emegency if you can't get home or find someone to put wood in)
Thanks to all you guys. I've got it now. I think both way would work. Seems like if you have the existing infrastructure (inside boiler) your job is pretty much done. I do think anyone with an OWB needs to heat their potable water though (I think hot water is my greatest savings).
Scootermsp
ArboristSite Guru
Don't forget the pool
In the spring I will be hooking up the 20x40 inground pool into another exchanger (Marine Grade SS about $900). Heck why not it's right there and I can sell my propane heater for $500 to offset the cost.
In the spring I will be hooking up the 20x40 inground pool into another exchanger (Marine Grade SS about $900). Heck why not it's right there and I can sell my propane heater for $500 to offset the cost.
I'm at a crossroad !!!
It is time to make a choice to use or not to use a heat plate? I don't want to beat a dead horse:deadhorse: But, is it truly a preference to use a plate. I need some cold hard facts to the pros and cons. If using a plate and the fire goes out, the water will still circulate keeping the water from freezing, right? The boiler is set to 140 F and will maintain the house and the OWB just as it would if it was a direct hook up. Will you burn more wood with the OWB's circulator on 24/7 ? Seams that it will always be pulling heat out of the tank, thus more firing up of the OWB. Does it matter what size heat plate you use?
I figure if you going to buy a 30 plate for $340.00 you might as well go to a 50 plate at $500.00. Will you save in the long run with a better heat transfer? Who is the authority on this, or should I just flip a QUARTER ?
LT...
It is time to make a choice to use or not to use a heat plate? I don't want to beat a dead horse:deadhorse: But, is it truly a preference to use a plate. I need some cold hard facts to the pros and cons. If using a plate and the fire goes out, the water will still circulate keeping the water from freezing, right? The boiler is set to 140 F and will maintain the house and the OWB just as it would if it was a direct hook up. Will you burn more wood with the OWB's circulator on 24/7 ? Seams that it will always be pulling heat out of the tank, thus more firing up of the OWB. Does it matter what size heat plate you use?
I figure if you going to buy a 30 plate for $340.00 you might as well go to a 50 plate at $500.00. Will you save in the long run with a better heat transfer? Who is the authority on this, or should I just flip a QUARTER ?
LT...
Jkebxjunke
*Politically Incorrect*
if I am not mistaken .. the transfer plate should be rated close to your boiler size --btu rating shouldn't it? it would make sense if it was. too small of one and you wont get enough heat from your owb to heat your house.
I told him to go one bigger than his dealer recommended.
ngzcaz
ArboristSite Operative
Info I've gotten is to oversize rather than undersize. But dont buy a 500,000 btu unit if your house boiler is 100,000 btu ( unless you plan on adding an addition )
Scootermsp
ArboristSite Guru
BTU's????
How many BTU's will a standard 30 plate water-to-water heat exchanger be rated for ? Thank You in advance.
How many BTU's will a standard 30 plate water-to-water heat exchanger be rated for ? Thank You in advance.
ngzcaz
ArboristSite Operative
Dont know offhand but if you go on ebay and check flat plate heat exchangers
or similar sites the info should be there. I'll end up with a 30 as well even with a smaller home.
or similar sites the info should be there. I'll end up with a 30 as well even with a smaller home.
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