Pump Question

[magnumhntr]

Just curious as to what difference pump speed/volume has on an OWB fire times/wood usage? My woodmaster 4400 came with a taco011. The heat loss through 105' (65' of underground and 40' boxed in and insulated along the garage wall) to my sidearm is 5 degrees. The temp setting I have are 155-175, and it fires about every 2 hours. I load the stove about half full twice a day with seasoned softwood that was given too me about 4 years ago. I do use less wood when burning my good seasoned wood, but I need to use up the "junk" first as I have about 5 more cords of it. Anyway, my question is would a smaller pump like a taco007 be more efficient as it would move the water slower, in theory putting less cold water back into the 112 gallons around the firebox, and needing less cycles to keep the water temp up. I know the OWB are not efficient in design, but am looking for ways to maybe maximize any efficiencies that can be gained.

Hope this made sense.

Thanks!

Chris

 

[KsWoodsMan]

A smaller pump will move less heat, in the form of hot water, from the firebox/boiler to your home. So I guess it will save wood, at the expence of a possibly colder house.

 

[projectsho89]

Actually, the correct answer as to which pump size is "best" is - "It depends"

Move water too fast and there isn't enough time in the exchanger for transference to effectively take place. If you move it too slow, you'll drop the temperature of the return water too low and you'll be unable to produce heat efficiently.

A typical design value of 20F temperature differential is often used in systems, you'll probably have to play with it to see what's most efficient.

Steve

 

[KsWoodsMan]

I'd rather have the return water and the house warmer by using a pump a bit to big than to have a cold house and cold return water knowing the water in the boiler was toasty warm out there.

The idea is to transfer the heat from the boiler to the house effectively. Not to cool the water before returning it to the boiler. Slowing the pump will get less heat from the exchanger because of less flow.

magnumhntr - To conserve more wood in the boiler try arranging the wood so it burns differently, crossways instead of longways in the burner chamber.

 

[mtfallsmikey]

If return temps are too low..condensation could form in the boiler...bad news. my return temp is within 5 deg., loop is 90' one way, but did mine with primary/secondary piping, not running the hot water thru the HX's constantly. My firing intervals run around 2 hrs. in mild weather, 20-25 min. in cold windy conditions.