Outdoor Wood Furnace Info
All-Purpose OWF Discussions => General Outdoor Furnace Discussion => Topic started by: terpjr on March 06, 2017, 07:17:31 PM
-
Hey guys,
Have had a Woodmaster 4400 for 9 years now...
It is used to heat a 3000 square foot house - old farmhouse, newly (But traditionally) insulated (meaning no blown-in etc..). Furnace is 75' from basement. So, 150' loop.
I burn 15+ Cord of hardwood (of varying degrees of seasoning) in the Oct-May heating season. Upstate NY but not way upstate - Albany area. There is a fair amount of wind, also heats domestic hot water.
In reading here, I feel as though I am using too much wood. We do keep the house fairly warm all winter long.
So, how do I assess my system -
Woodmaster 4400, pumped by Taco 011 to plate exchanger, circulated to furnace and distribution manifold by an 007 or 005 pump (furnace is oil furnace, sits unplugged), circulated through the house by taco 007's.
I have an infrared gun style thermometer.
What is the best way to get temp readings on PEX?
What is an ideal drop in temp from leaving OWD to entering OWB when calling for heat? When not?
How much temp should I expect to lose before it gets to exchanger?
How much should I lose in exchanger?
Is there a way to turn up or turn down the 011 pump?
What about stack temp? How do I measure that? What is ideal?
I know there are a lot of questions that are answered on the site...but sometimes I feel like I am not quite understanding stuff..
-
Also,
How often do people clean ashes from their furnace?
-
In a non-grated unit like a 4400 I would think you'd want to leave 3-6" of ash bed all the time. Whenever it gets higher shovel some out.
Temp reading on the surface of the Pex will read low. Shoot a piece of electrical tape on the pipe. You can check temp differences at different locations but not an accurate reading of actual water temp. For that you'd need a dry well in a tee.
-
You also need to take into consideration that the older conventional boilers only had efficiency ratings of 30-40% while the new gasifiers are in the neighborhood of 70-80%.
The older ones only 3-4 pieces of wood out of 10 actually reach your house, gasifiers 7-8 pieces out of 10 actually make it to your house.
My old homemade conventional (direct knock off of a Central Boiler) had stack temps around 700 degrees or better if it was really cooking, the G series is usually under 300 degrees.
-
Besides stack temp, if it is smoking that is unburned wood going up the chimney that a gasser would be converting to heat.
-
If you see stack temps over 750 degrees (from a local dealer) then your stove is blowing heat out the chimney, try dampening the air flow. Secondly I don't like to see return temps back to the stove more than 25 degrees difference. If this is the case you need more flow. My stove the water temp reaches its first stop at the water heater with a temp of 178 and then hits the furnace. When it leaves the heat exchanger the water temp is 165 (furnace fan on) when it gets back to the stove its roughly 163 or so. If I turn my pump speed to medium I see return temps of 154 to 156. I believe this can help the stove out so it does not have the temp shock. It can take a lot of energy to overcome this and having more flow the heat won't get pulled from as much water in one place rather than over a larger amount of water. Sorry I'm not technically correct with all my wording like some here are but I'm sure you can understand.
Another thing you may want to check is the water temperature leaving the stove and the water temperature arriving at the house. You want to make sure that you are not losing any heat in your underground lines. This can drastically reduce the efficiency of your stove more than anything else I believe. That would be the first thing I would check second I would check flow and third I would check air flow into the burn chamber
-
Ok...
I took my infrared thermometer and a few pieces of elec tape and I got readings that were all over the map.
I understand that it will not be my actual water temp...
But I was getting my return line warmer than my send line...my temps in the basement 30 degrees lower than my temps at the furnace (both send and return)...
I get the feeling that I am not getting accurate numbers...any tips?
Also...how in the world do I measure stack temp?
-
Ok...
I took my infrared thermometer and a few pieces of elec tape and I got readings that were all over the map.
I understand that it will not be my actual water temp...
But I was getting my return line warmer than my send line...my temps in the basement 30 degrees lower than my temps at the furnace (both send and return)...
I get the feeling that I am not getting accurate numbers...any tips?
Also...how in the world do I measure stack temp?
I’m not a huge fan of infrared guns, I have an instant read pyrometer I use on lines, place the tip on the line and hold for a few seconds, the line has to be all the same kind to get any real readings, taking readings of pex, black pipe and copper will guarantee readings all over the place. If us a IR gun wrap the line with black tape and hold the gun right on the line to avoid getting any peripheral readings.
Usually a candy thermometer won’t read high enough on the old boilers for stack temp, again a pyrometer comes in handy.
-
Hey guys,
Have had a Woodmaster 4400 for 9 years now...
It is used to heat a 3000 square foot house - old farmhouse, newly (But traditionally) insulated (meaning no blown-in etc..). Furnace is 75' from basement. So, 150' loop.
I burn 15+ Cord of hardwood (of varying degrees of seasoning) in the Oct-May heating season. Upstate NY but not way upstate - Albany area. There is a fair amount of wind, also heats domestic hot water.
In reading here, I feel as though I am using too much wood. We do keep the house fairly warm all winter long.
So, how do I assess my system -
Woodmaster 4400, pumped by Taco 011 to plate exchanger, circulated to furnace and distribution manifold by an 007 or 005 pump (furnace is oil furnace, sits unplugged), circulated through the house by taco 007's.
I have an infrared gun style thermometer.
What is the best way to get temp readings on PEX?
What is an ideal drop in temp from leaving OWD to entering OWB when calling for heat? When not?
How much temp should I expect to lose before it gets to exchanger?
How much should I lose in exchanger?
Is there a way to turn up or turn down the 011 pump?
What about stack temp? How do I measure that? What is ideal?
I know there are a lot of questions that are answered on the site...but sometimes I feel like I am not quite understanding stuff..
I got same stove, heating 1/2 of what u are.
I have a shorter run, but not much.
I use 1/2 the wood u do. [6 bush cords]
Most of the heat from these stoves goes up the chimney.[as Martin says]
In my opinion your not doing too bad on the wood consumption for 8 months use.
If I did not have free wood, I would not bother with the whole exercise.
-
If you want to talk wood consumption and efficiency,,my neighbour has it all figured out.
He's got a little airtight cast iron wood stove in the basement.
He hooks up a bunch of redneck piping and a fan on the back of the airtight,to get the heat upstairs.
He heats the basement and upstairs of the 2 bedroom 1100 square foot house with less than 3 bush cords of wood.
No he can't heat the dhw ,,,and he's got the fire inside the building,,, but 3 cords a year ,,,,and it's cold here.
That's redneck efficiency
-
Thank you for the explanation.
Held my IR thermometer against the pex,
Ended up a 13 degree difference between stove exit and return. I feel like this was pretty good.
A mild night...I'm going to keep checking, see what I average.
Thanks for the help.
-
Hey guys,
Have had a Woodmaster 4400 for 9 years now...
It is used to heat a 3000 square foot house - old farmhouse, newly (But traditionally) insulated (meaning no blown-in etc..). Furnace is 75' from basement. So, 150' loop.
I burn 15+ Cord of hardwood (of varying degrees of seasoning) in the Oct-May heating season. Upstate NY but not way upstate - Albany area. There is a fair amount of wind, also heats domestic hot water.
In reading here, I feel as though I am using too much wood. We do keep the house fairly warm all winter long.
So, how do I assess my system -
Woodmaster 4400, pumped by Taco 011 to plate exchanger, circulated to furnace and distribution manifold by an 007 or 005 pump (furnace is oil furnace, sits unplugged), circulated through the house by taco 007's.
I have an infrared gun style thermometer.
What is the best way to get temp readings on PEX?
What is an ideal drop in temp from leaving OWD to entering OWB when calling for heat? When not?
How much temp should I expect to lose before it gets to exchanger?
How much should I lose in exchanger?
Is there a way to turn up or turn down the 011 pump?
What about stack temp? How do I measure that? What is ideal?
I know there are a lot of questions that are answered on the site...but sometimes I feel like I am not quite understanding stuff..
I got same stove, heating 1/2 of what u are.
I have a shorter run, but not much.
I use 1/2 the wood u do. [6 bush cords]
Most of the heat from these stoves goes up the chimney.[as Martin says]
In my opinion your not doing too bad on the wood consumption for 8 months use.
If I did not have free wood, I would not bother with the whole exercise.
I agree with this statement. I've been doing this for 10 seasons now. I'm heating over 3000 sq ft and dhw. As much as I love my boiler there is no way to make it effecient. I've tried everything, more air/less air, large diff/small diff. heat reclaimer in the chimney, rounds/splits. I checked it once at a cold start by weighing a small amount of well seasoned wood and seeing how much the temp of the water rose with no zones calling for heat. It was low 30% tops. That was burning full out with no idling. If you figure idling losses during a normal day it would put it somewhere in the mid to upper twenties(ouch). Don't get me wrong, I love the simplicity, and safety of the boiler but I use a lot of wood, at least 12-15 cord. I watch most of the heat going out the stack. There is no smoke if there was only a way to transfer the heat better. Oh well, it paid for itself 7 years ago and I have a lot of wood.
-
You'd be amazed if you tried a downdrafter. My wood consumption dropped dramatically. And the new ones are very easy to use. No brushing tubes, etc.
-
Did I happen to read water temp is 30 degrees cooler at the house than the stove? If this is so, then we have found your problem!
-
Problem is going up the stack by design.
-
You'd be amazed if you tried a downdrafter. My wood consumption dropped dramatically. And the new ones are very easy to use. No brushing tubes, etc.
:post:
-
Lol...my 30 degree temp problem was due to inaccuracy in my thermometer.
It was reading 30 degrees lower in the basement than it was at the furnace...send AND return (lol).
-
Hello terpjr
You have a really good question there. I'm not a fan of infra red thermometer either. They Work good on engine exhausts to check individual cylinder output temps. And eng temps. Yes the temp wells are very good and that is what I put on all my furnaces.
It is important to make sure your heat exchanger is set up to counter flow the water ⏫⏬ !!
Assessing efficiency. Can be done but it needs to be broken down into compartments,
The btu requirements for the house or heat load. (Will change with temperature of course).
Btu loss to the house. (Underground pipe type and size. )
The efficiency of the heating unit. I like MLappins analysis on wood consumption.
if the house is comfortable and warm all winter. And the boiler is at 180deg F are you comfortable with cutting and handling all the wood that is not going to your house.
I am in the Albany area often and would stop in to look at your system.
Or you could stop up and have a look at the G-200 in action. I'm just above Saratoga.
I have to go to freehold NY to do a heat exchanger set up. That was done wrong. So I will be going by that area. You can call me. Or pm me.
-
Lol...my 30 degree temp problem was due to inaccuracy in my thermometer.
It was reading 30 degrees lower in the basement than it was at the furnace...send AND return (lol).
Excuse me for reading that wrong. Even after you explain it here, still sounds wrong!
If u take temps at the stove and in the basement they are the same if you use the same infrared temp gun... is that what I should be understanding?
My temp gun is within 2 degrees of my inline thermometer.