OUTDOOR WOOD BOILER-------OT

WE had a small indoor wood boiler in our garage for 25 years. At night we would close the damper and the fire would go all night. It got a hole rusted in the water jacket. We installed a bigger out door wood boiler that the draft on the door is opened and closed with a magnet hooked up to electric power. The old boiler was manual open and close..

During the night when we would like to have the draft closed--it is open due to the fire getting lower and it calls for more draft. It is 80F right now here in Michigan--in the house,.

We like the fire to hold overnight, which it does with no problem, but it just puts out tooo much heat.

What do I need to do????? I have been burning wood for over 55 years....THANKS

too much no common sense modern yuppibul-shyt idiots designing .. you mite consider a timer that cuts out the magnet,. set it for 4 am to open and your house will be warm for breakfast.

Why is the house allowed to be heated to 80?. My furnace fan is controlled by a thermostat. And the water temp is a constant 150-180 degrees depending on how cold it is out and needed to heat the house.

More directly the draft door could be controlled by a timer, or indoor thermostat, wired to override the water temp control.

That is my question---80F---we have hot water heat floor registers NO FANS. THE OUT DOOR BOILER SENDS hot water to a heat exchanger. The out door wood boiler is not a pressure system. The house system is a pressure system. These two systems are linked by a HEAT EXCHANGER...Both systems have their own PUMP and the pumps are set to run all the time. If the pressure side pump is not working the system builds too much heat and also too much pressure..

We have three hot water systems and none of them have both pumps running full time. Your system is setup wrong.

The circulation pump from the stove (outside circuit) should run anytime the water is above your set temperature. IRC ours are set at 180 degrees for this. This is the outside loop. Then the house or inside circuit should be setup to be controlled by a thermostat in the living area. This should run that pump ONLY when the house needs heat.

Your current system is trying to regulate the water temperature for the entire system by controlling the fire/draft. That systems is doomed to fail because of the different demands on the draft. You have to have a minimum draft just to maintain the fire. So in your case I would bet that your "new" outside stove is larger than your old inside one was. So even with a low fire it is generating more BTUs than you need for the house right now. So you need to stop putting the BTUs in the house. This is why you need to control the house pump separately.

With the outside circuit circulating the water it is unlikely to overheat the water. Also you can make the minimum draft lower. Most stoves are adjustable. If not make the opening smaller and see how it works. If it is a program running the blower every so often then your will need to see if you can change it to longer intervals.

Your "new" system needs to be controlled differently than your old one because your new system can generate more BTUs then your old one. Manually controlling the old system worked because it did not have much extra capacity. Your new system does so you need to have a better control then you had.

Mine work like this. The outside circulation pump runs whenever the water temperature is above 180 degrees. The forced draft runs when ever the water temperature is under 220 degrees. (mine are pressurized systems. If yours is not then your temperatures are just lower so you do not boil off the water) The house circuit only runs when the house thermostat demands heat. The draft fan does not run when the water is up to temperature. The draft fan housing has a small hole/slot in it to allow a minimum draft to keep some fire in the stove. It does not take much.

I would bet that your minimum draft is way too much. This can also be a program issue on the newer stoves. Mine just use a mechanical control. Some of the new stoves run the draft blower every so often just to keep the fire going. You need to run yours less.

I still think just controlling the house circuit with a thermostat would be all you need to do.

P.S. If your get your setup to really regulate the draft to a much low rate at "idle" then be careful when you open the door to add wood. If the stove is smoldering and you open the door an give it a big breath of oxygen you can get a big BOOM. On my first stove you could get the door open very fast and it would flash burn if you where not careful. The next one we had had a complex handle latch that took time to open. This way it would slowly fire up. The newer ones we have run the fan for a while before you can get the door open.

Then you need to be set so the burner pump is running full time. This keeps the plumbing from freezing and the temp in the boiler more even. The house pumps should be controlled by a thermostat like my furnace fan.

Onefarmer has it right. The pump is designed to run all the time on the furnace. Then the one in the house needs to run on a thermostat. But why have the pressurized circuit in the house. Just let the water circulate with the pump from the furnace then use a zone valve to divert it to a bypass when the house reaches temp desired. That is how dad has his and is works fine his is baseboard heat with an outside wood furnace.

Might help to know what brand you have . My dad has a Hardy that has forced air blower on the stove and the pumps only run when heat is called for. I have a central Boiler that just has a damper on the stove and the pump runs all the time. I burn year around to heat my water and have a diversion valve for the summer. For house heating I have 2 air handlers in the house and an old radiator in the basement. The forced air handler are on a stat and the cast radiator has a manual bypass valve.

You might want to go to heatinghelp.com and go to "the wall" and boiler experts from all over the country are willing to help you...

Turn your water temp down, On mine we keep the house 73 to 74 and the pump runs all the time. You will get some heat from the water when the furnace blower is off but nut much. When it gets colder outside turn your temp up to around 160 to 170. Right now mine is at 145 and I load it every 2 days. If you shut your pump off depends on furnace location you may lose the prime in it causing you to get air in the line

You need to maintain a minimum core temp of 140F in any boiler to prevent corrosion and premature rust outs. New boiler mfgs know that and put controls on them to maintain that temp as a minimum. You will void your warranty if you alter that feature.
(Former dealer and installer of several brands)
Loren

When my dad used to heat our house with an indoor wood stove, the first few years, burning the plentiful oak we had, we were often roasted out of the house in the Fall & Spring even with the stove dialed back to the max.

We solved the house overheating issue by burning lower BTU Poplar wood during the milder parts of the year. Fire kept burning, but because of the lower BTU in the wood, produced less heat.

No, it doesn't. The indoor loop can't get any hotter than the outdoor loop, and if you have a proper expansion tank on the indoor loop, you won't have issues with pressure. Turn your water temperature down on the outdoor loop, paying attention to what Loren says about making sure you don't turn it down too far, and that will help, and then cycle your indoor pump on a call for heat from the space, and that will help some more.

Bear in mind that your new boiler is probably rated at around 300,000 BTU, which is about three times bigger than most residences need. The manufacturer has its sequence engineered to maintain a fire continuously, so even at a smolder, your system is adding heat to the outdoor loop. In this kind of weather, that may indeed boil your "boiler," since it's open to atmosphere and water boils at 212 degrees at atmospheric pressure. If that happens, you're going to need a bypass in the house to keep from overheating the indoor loop. I know that many folks on this board are satisfied users of outdoor boilers, but I think they should be outlawed. The best of them is about 20% efficient, and the amount and toxicity of the pollution coming out the stack is literally breathtaking. If you have a nearby neighbor downwind, you're not doing him any favors.

Thank you fellas for the great information..The inside boiler is an oil fired boiler used for a backup and it is a pressure system. The heated water from the outside wood boiler is transferred to the indoor boiler via a heat exchanger. If the pump on the inside oil boiler is not running it builds up too much heat and pressure and the pop off valve goes off.
We like the backup oil fired boiler for when we are away for a few days--we take many trips to the hospital at UofM for my lady. I really really appreciate that you folks took so much time to help us......add more info. if needed......

Theoretically, your indoor boiler shouldn't be lifting the relief valve if it's being kept at 180 degrees, unless your expansion tank is too small, or gone bad I would check that.
If that's ok, you could look at putting a bypass valve on the primary loop side of your heat exchanger. You could set it up such that the primary loop bypasses the exchanger until your secondary loop calls for heat
Pete

Unless the fire goes out when your magnet has it shut off, of course. Then you'll have a cold house and a frozen boiler. How do you spell the cuss words that you'll be saying then?

This is the only guy here who knows what he's talking about. Follow his recommendations. The problem is most residential boilers are half-a** installed and "will work" under the right conditions. You need to get a professional involved both to get the system working properly but safely also.

That explains why when I adjust the temp on my readout it will not let me set it below 140. It just stops at 140 not that I would ever want to go that low

MORE INFO. The thermostat on the outdoor wood boiler is set at 185F-----Thinking that is too high from info. gathered here from y0u good folk......going to dial that down some....