OWB ? House too warm

[Coldfront]

My daughter just moved into a a totally remodeled 3 bedroom 1 full bath house with full basement about 1000 sq. ft including basement. House has a brand new Wood Master 3300 owb hooked up in basement to a new natural gas forced air furnace. I fired up the owb for the first time yesterday set at 170 degree water temp normal setting. Wood thermostat set at 72 in house. She said the house got up to 87 degrees inside house last night she had to open windows. Outside temp last night was down to 15f for the low. The furnace blower was not coming on but still too much heat. Is there no way to control how hot the inside house temp gets other than opening windows. Maybe the Wood Master 3300 is overkill for a well insulated house? W. M. 3300 is rated for 2,000 sq. ft. / her house is 1,000 sq. ft. I am afraid to see how warm it gets inside the house when it is 40 degrees outside.

 

[Marshy]

Sounds like it's over sized for sure and you have a learning curve on how to use it. My guess is your going to have to load the firebox for the weather conditions. Also things to consider are maybe the firebox has an air leak and it can't dampen the fire low enough or maybe you need to make sure all the controls are working properly.

 

[Coldfront]

The thermostat on the owb seemed to maintain a steady water temp of 170, the shut down temp is set at 120 for if the fire runs out of wood. It seems to me they should have some type of hot water bypass so that so much hot water is not always going through the heat exchanger in furnace when it is not needed, engineers can't come up with something like this?

 

[Marshy]

The thermostat on the owb seemed to maintain a steady water temp of 170, the shut down temp is set at 120 for if the fire runs out of wood. It seems to me they should have some type of hot water bypass so that so much hot water is not always going through the heat exchanger in furnace when it is not needed, engineers can't come up with something like this?

It's up to the installer that designed the heat loops and built it to do it properly. Being so oversized it should have a load reject loop like out to the garage. Or put less wood in the stove.

 

[Coldfront]

I thought about loading less wood, but that would kind of defeat the purpose of a owb and 12 hour burn time.

 

[olympyk_999]

maybe rig up a thermostat to open and close windows to control temp, or see if the neighbor wans some heat
1000 sf seems way small for a owb to heat properly...

 

[jlromine76]

Wonder if the water that is continuously circulating is warming up the place as well. I have warm spots on my floor where the water lines run through the crawlspace which is kind of nice on the hardwood floors. Maybe have the pump shut off when the forced air furnace isn't calling for heat to keep the hot water out in the boiler instead of always warming up the heat exchanger. Seems like it may also be an issue with her thermostat possibly inside the house and the temp is set wrong or it might be bad. I had one die on me and it was kicking on and off all the time so I had to replace it.

 

[Marshy]

Wonder if the water that is continuously circulating is warming up the place as well. I have warm spots on my floor where the water lines run through the crawlspace which is kind of nice on the hardwood floors. Maybe have the pump shut off when the forced air furnace isn't calling for heat to keep the hot water out in the boiler instead of always warming up the heat exchanger. Seems like it may also be an issue with her thermostat possibly inside the house and the temp is set wrong or it might be bad. I had one die on me and it was kicking on and off all the time so I had to replace it.

The main problem with your suggestion is that a fire is still burning and therefore still adding heat to the boiler water. If you turn the pump off the boiler would eventually overheat if the consumption is less that the heat added by the fire. If he had a heat reject loop then it would work perfectly like you suggest and could program the reject loop to kick on if the boiler water temp reached 180F or something.

 

[Need2Saw]

turn the water temp of the boiler down from 170, make sure the normal thermostat is not "fan on".

 

[cantoo]

I would guess you're not doing something right.
My OWB thermostat is set at 170 with draft blower cut in at 150, doesn't matter what the house size is the water will be maintained at 150 to 170. If I have no heat (exchanger) turned on in the house then the draft blower would not come on until the temperature dropped to 150, such as the summer, blower doesn't come on for several days sometimes. OWB is only controlled by the aquastat set temp.
If the house is only 1000 sq ft it just means the draft blower just won't come on near that often, fire will "idle" longer. If the thermostat was set at 72 and the house went to 87, then there is something wrong with the thermostat. Fan should have shut off at 72. Might get hot as heck at the exchanger but the rest of the house should stay the same temp as thermostat is set.

 

[NSMaple1]

The boiler is oversized for the house. But it still shouldn't heat like that, there is something wrong with the install or the controls & operation.

 

[Oxford]

I will bet the donut against the hole that this is piped so that there is constant flow from the boiler through the heat exchanger in the furnace plenum. If so, and in relatively mild weather with a tight house, then that constant heat source is going to warm the air stream and cause air movement by convection, causing the house to overheat without the thermostat ever calling. There's nothing mechanically or operationally wrong with any of it, except that it's too big for the home and has about the same relative engineering sophistication as a pointed stick.

 

[tawilson]

The thermostat on the owb seemed to maintain a steady water temp of 170, the shut down temp is set at 120 for if the fire runs out of wood. It seems to me they should have some type of hot water bypass so that so much hot water is not always going through the heat exchanger in furnace when it is not needed, engineers can't come up with something like this?

They do make control valves that do this and it probably would solve the issue.

 

[lindnova]

They do make control valves that do this and it probably would solve the issue.View attachment 471877

Yep. Sounds like heat is rising and heating the house without the furnace fan coming on. You likely will need to get a control valve. It can be wired low voltage to turn on with the propane furnace fan. Also make sure the furnace fan is wired to come on without the propane firing at the same time.

Mine has no valve and we notice too much heating if it is warm outside during the day (above 60°). Not much of a problem for us.

 

[Need2Saw]

They do make control valves that do this and it probably would solve the issue.View attachment 471877

if you install that valve and actuator, you will deadhead the pump. The correct way is to pipe in and install a 3-way valve.

 

[jgoodhart]

The pump to the house has to be running all the time and the thermostat controls the fan. Need to wire so the relay in that back of the stove can control the pump and a 2nd relay for the furnace fan.

 

[cantoo]

Oxford, to fix this would you suggest hooking the pump up to the thermostat so the pump on runs when there is a call for heat? My son has that problem in his house ( I heat 2 houses with my OWB) the room that the furnace in is gets really hot just from the water flowing. He just shuts the pump off when it's warmer out.

 

[hupte]

Oxford, to fix this would you suggest hooking the pump up to the thermostat so the pump on runs when there is a call for heat? My son has that problem in his house ( I heat 2 houses with my OWB) the room that the furnace in is gets really hot just from the water flowing. He just shuts the pump off when it's warmer out.

I also shut the pump off when its warm out. usually above 68*F before I shut my pump off. or the OP could set up a bypass valve so the hot water wont flow thru the HX when its warm out.

 

[hupte]

My daughter just moved into a a totally remodeled 3 bedroom 1 full bath house with full basement about 1000 sq. ft including basement. House has a brand new Wood Master 3300 owb hooked up in basement to a new natural gas forced air furnace. I fired up the owb for the first time yesterday set at 170 degree water temp normal setting. Wood thermostat set at 72 in house. She said the house got up to 87 degrees inside house last night she had to open windows. Outside temp last night was down to 15f for the low. The furnace blower was not coming on but still too much heat. Is there no way to control how hot the inside house temp gets other than opening windows. Maybe the Wood Master 3300 is overkill for a well insulated house? W. M. 3300 is rated for 2,000 sq. ft. / her house is 1,000 sq. ft. I am afraid to see how warm it gets inside the house when it is 40 degrees outside.

what does she heat besides the house? like shop, domestic hot water, anything, etc?

 

[Del_]

It seems a damper in the hot air duct work than could be easily overcome by the force of the hot air furnace fan would stop the unwanted over heating. If this damper could be locked in the open position during really cold weather to allow convective air flow it would be nice. If the boiler is heating DHW then cutting off the boiler to house heating water loop is going to kill DHW, too. Not good.