Greenwood 100 experience

[Neophyte]

Bought Greenwood 100 in August from local agent and hired installer. Installation is indoors, linked to oil-fired boiler, for hot-water baseboard heating house of about 4000 sq ft. First-time experience with a wood boiler.
Installation proved lengthy, at about 70% of the price of the boiler. Duration of installation was due inter alia to the flow valve provided by GW not being the same as the one specified in the installation guide. Other issues involved the electrical interface with the oil-fired boiler.
After two or three successful trial runs lasting a day or two, a longer run was begun. It ended abruptly on the fifth day when the 1” pex hot water output tubing burst, which then produced overheating because hot water was not reaching the heat dissipation fan circuit. The output pipe was copper for the first 4 feet, then 1" pex, and the burst was 3 feet from the start of the pex (i.e. about 7 ft from the boiler). Simple repair, replacing pex with copper pipe. In hindsight, the aquastat controlling the fan operation may have been set too high; a lower setting might have eased the heat/pressure buildup and precluded the pipe burst.

My thoughts are (i) acquiring and using a GW hydronic wood boiler is not for the faint-hearted; (ii) GW could do better in guidance and training for the installation process; (iii) pex tubing should NOT be used near the hotwater output; (iv) a draft inducer may be useful but does not appear essential; (v) wood consumption projected for a month would be about two full cords; (vi) feeding wood to the boiler every 3-4 hours is about the norm for the inexperienced, though after 6-8 hours it is still possible to get a good burn again, and one needs to take account of such factors as wood quality and quantity loaded, external temperature, programmes set on thermostats...
I would welcome comments and suggestions from those with more experience!

 

[henfruit]

jimbo he is from your state. you explain!

 

[91220da]

Neophyte,
Too bad about the burst. No offense but it sounds like a user, installer issue. Have been running a gw 100 since Oct.28 non stop with no problems. Pexalpex is rated for 230 degrees for a period of 4 hours. What kind of temps and or pressure were you pushing? Hopefully you are set up with expansion and pressure relief safe gaurds. I am easily getting 8 -10 hour burn from mine but I am only heating 2100 sq. ft. I agree that Greenwood could provide more indepth and clearer instructions for the instal but I installed mine myself with the help of a very knowledgeable HVAC tech. friend. Have only used 2 cords since start date and my pex starts about 2 feet behind the boiler coming off of black iron. I am not sure if you are using programable thermostats or not but through my research I found that they are not recomended for use with the greenwood. The up and down temp cycles kill the efficiency and heating potential of the greenwood. It is best to get the refractory up to the 1200 degree range and then keep it there. Best way to check the refrac temp is with an I.R. thermometer. Good luck with the future use. I did go through a learning curve with mine but feel it is totaly worth while now that it performs as well as it does.

 

[Neophyte]

Thanks 91220da, that's helpful, and I am grateful.
I'm sure you are right about the burst, as regards possible cause and responsibility. And so far, the GW 100 delivers heat and I am not dissatisfied with it at all, just curious about getting its management right!
Your wood consumption rate sounds, for your square footage, comparable to what I project for mine.
Indeed I am using programmable thermostats, and was not aware that they are not recommended!
Again, the manufacturer's information and guidance could be better - or perhaps I missed
something...
Am I correct in understanding that you recommend I set my three zone thermostats at a steady temperature? With no changes for day and night? Nor for significant changes in outside temperature? In other words, do you adjust your thermostats at all, and if so when?
The refractory temp and infrared thermometer are quite new ideas for me: I see there are all kinds on the market - any type/brand your recommend, or price range? How actually does one check the refractory temperature with one?

 

[91220da]

Glad you like the furnace. I have our two house thermostats set at 66 degrees and honestly, the thermometers around the house usually read 68-69-70. I attribute this to the internal temp of the oil furnace always holding around 160 or 170 degrees. When the house calls for heat and the zone valves open, you have instant temp at the baseboards compared to the oil gun fireing and the lag or delay for the water to heat. I do not or have not touched the thermostats since Nov.1 One thing I did do about 5 hours into the first fireing was to turn the thermostats way down (40 -50 degrees) so the house zone circulator did not run then I turned the greenwood aquastat way up (190- 200) and supervised the burn carefully. This helped to bring the greenwood loop up to 190-195 and heat the refractory. once it was all up to temp. I readjusted the greenwood aquastat to about 180 and set the house thermostats at the 66 and all has been well. I do have greenwoods heat retention kit which I would recomend. That prevents the greenwood from fireing over 200 and closes the damper when the return water drops to 140. Helps to keep the heat in the fire box instead of drafting out the chimeney. I can check on the brand of IR thermometer I think it is a Master temp or something like that. I bought it from my Snap On tool dealer but I believe it is an import brand anyway. I paid $55 for it and have seen similar units for 50 to 100 through Northern tool company. It is point, shoot, and read the temp. Be sure to check, some of them only go to 750 or 800 degrees. I think mine only actually reads to 1150 but it will display "OVER TEMP" when above that. It is fun to check all kinds of things like the difference in temp between your window caseing and the wall of your house. Helped me to find spots where the cold air was rushing in around our well line in the basement. There are some good posts on here about not loading the fire box before it is time. You will use more wood than neccessary but again you are heating 4000+ ft. I follow the rules and don't relode the firebox until my supply water temp drops to 160 or lower. The coals and burning embers will maintain heat for quite awhile if the refractory is heated fully. Hope any of this is worth your time. Burn On!
Rich

 

[trailhound68]

Neo, Tell me you did not install it in your house. Anyway, let us in on more details about your installation when you start having problems or issues. What kind of wood supply do you have? Do you split it? Etc.

 

[Neophyte]

Again thanks to 91220da for good tips - they certainly make it easier to get a longer burn and to time the reload. The heat retention package sounds interesting!

Yes, trailhound68, I do have it indoors, in a fairly large basement, with 3-4 cords wood supply adjacent. The alternative would have meant probable difficulties and costs digging a trench for the pipes, new chimney issues there, and unconscionable operational treks to garage to check and reload, so I am not at all unhappy with its basement location, and do not have significant smoke or other problems (pipe burst excepted!). My wood supply this season is what I had and what seasoned wood I could get in the Fall; it is clear that I shall be better off next season with much less split wood and more round logs.

 

[trailhound68]

Good for you, Neo. I wish mine could be in the basement, the heat gain from the unit is awesome, but the smoke.
Are you on a masonry chimney or what? Have you burned any big rounds yet.

 

[Neophyte]

Trailhound, I've burned a few big rounds and noticed how much longer they last, so I keep the few that I have for the overnight hours.
Next season I'll have to find a good supply of unsplit rounds.
The chimney is about 25 feet, and has a metal liner.
Smoke is noticeable in the basement when I forget to check first whether the damper is open... but otherwise OK.
Yes, the heat from the unit keeps the basement warmer too.

 

[trailhound68]

What I do when I want to load and the damper is closed is to simply turn the aquastat up. Don't forget to put it back of course.

 

[ISeeDeadBTUs]

Sorry, at a client's office, so this will be short . . .

1) Tell me you didn't put the GW inside
2)Look at the thermometer. Now is NOT a good time to be trying to figure out how to run your hydronic!
3) If you are loading every 3-4 hours, something is wrong. What are you using for "wood"?

Jimbo