New here and trying to better my system. Hardy KB 125 5- 6 cords per season. Southern Indiana

[Operator125]

Hello everyone, I am a new member but not to wood burning. I Have a Hardy KB 125 outdoor wood burner with 95' 1 inch thermopex.
I installed the system in Oct of 14. I made the mistake of the Junk 1" pex bubble wrap and just dug it up and replaced it with the thermopex. The bubble work good until water breached the tile early last January and I went from burning a cord every three weeks to a cord a week. I am using a
Taco 2400 20 at the unit and in the house of a grundfos 3 speed pushing a 18x22 coil and a 40 plate DHW exchanger.
The problem I think i have is to small of lines going to the coil and the plate exchanger. Total of 280' 5/8 pex al pex to and from the exchangers.
I just install 9 thermowells before and after plate exchanger, H coil, underground lines, and exiting the water heater.
I am ordering 1" pex to replace the 5/8 pex al pex to get more gpm and lower my delta T.
My house is 2000 sf 9' ceilings with 15' ceilings in the living room and a bedroom with 13' ceilings and a full half finished basement.
I will start burning the week of Thanksgiving until about mid April using around 6 cord with the old plumbing. I am hoping I can eliminate some wood usage by changing over to the 1' thermopex and the 1' pex from the 5/8 pex al pex.
Any advice or criticism would be appreciated.

 

[Woodman1]

Your not going to save any wood by changing the indoor pex. At best you might save a little electricity from lower head pressure.

 

[maple1]

Not really much to input from here, except that at 5-6 cords per year, it sounds like you're doing pretty good now. Don't think I would expect much of a savings over that, now that you have all your heat getting into the house from the underground change. I might make it work better and the circs use less juice, maybe, although not picturing how the 280' of 5/8 fits into your system.

 

[Operator125]

The 70' is to the h coil and plate exchanger from the basement wall where the thermopex comes in. Two hot and two returns x 4 = 280'. I was thinking if I could raise my gallons per minute throughthe H coil that it wouldn't cool the water down as fast which would be less wood consumption?

 

[Operator125]

This is at the wall where it splits from 1" pex to 5/8 through the manifolds.

 

[Woodman1]

I understand your thought process, however it won't help your wood consumption. Think of it like this. If your truck has 1/4" gas lines, changing them to 1/2" won't help the mileage. The only reason you would upsize your lines is if the house won't heat to the temperature you want. You can push more btu's through a larger line which would also require more fuel/wood.

 

[Operator125]

When you put it that way it kinda makes sence.
I'm gonna delay the 1" pex for now and moniter my temps after I fire up in a couple of weeks. Iv been reading this site for a couple of years now and learning so much. I figured 6 cords was a bit much considering where I live. Thanks for your input.

 

[maple1]

I am thinking you should just need one pipe loop inside - in series through the two exchangers? If you get to making changes.

I think from all I have read about people posting their wood consumption with an OWB, that I don't think I have read of anyone using less than 6 cords annually. My memory isn't what it used to be, but really, I think I would be pretty satisfied with that. Not saying it couldn't be better, and without knowing your climate & heat load.

 

[E Yoder]

I would agree, pipe in parallel (domestic water first) with larger piping would allow use of smaller pumps, not drop wood consumption.

 

[Operator125]

When I install the 1" pex to replace the 5/8 Pex al pex and run to the plate exchanger then through the h coil will there be any need to keep the second pump? Or should I move it over to the return side to help push water back to the boiler? You can see from the pic the second pump is on the hot side. If I moved it I wouldn't need the manifolds anymore either.

 

[49chevyman]

Have you though about adding storage?

 

[Operator125]

I'v tossed the idea around. I guess it would depend on how much less I would burn. My burn season is from around the week of Thanksgiving to April 1st ( 20 weeks). Cold winter I use about 6 cord, mild to average winter around 5 - 5.5.
I'v been on many wood forums reading about other guys setups and I'm starting to think I don't have it so terrible as far a wood consumption. I think its reading about how detailed some of these guys get with their equipment makes me want to take the next step and see how efficient I can get and prove it to myself by understanding the numbers. If a storage tank would save me a cord or more I would consider it.

 

[E Yoder]

Shouldn't need the 2nd pump at all.

 

[Operator125]

I was thinking the same thing. Couple of weeks from now I will strip the 5/8, pull the 2nd pump and run the 1".
Only problem left is my coil reduces down to 3/4, will that restrict flow going from 1" through the coil?

 

[E Yoder]

Might a little, but ¾ copper is about the same as the ID of a 1" pex fitting.

 

[Operator125]

I really appreciate everyone's help. Thank you.
The temps are gonna take a dive this Sunday in southern Indiana so I'm gonna fire up Saturday. This year I'll be able to accurately measure water temps so I'll post some details of my system and run some more info by some of you experts.
Hopefully everything will be within ideal range.