Experience with over heating of green wood boilers

[FishHawk 210CC]

I am looking at a new gasification boiler and one that was quoted to me was a greenwood. When reviewing the quote it had a $2100 option for a battery back up. Rep told me that they are required (heat dump) per code. He said conventional heat dumps ( high capacity registers with gravity flow) at a 10% boiler rating are not enough and they are seeing a lot of the boilers hooked up that way popping safety valves due to inability to dissipate excess heat.

Looking for some thoughts/experience on the issue

The other thing that concerns me is the extremely small water mass in the boiler (~6 gallons). System was quoted with no additional storage

 

[2.beans]

find an inverter charger and hook it up to your largest zone for a dump zone. i bought two on ebay for 150 each .one died the other still works good. the ebay seller wont stand behind his warranty, so find from someone honest. cheap solution

 

[antknee2]

I use a Tripp.Lite 1000va UPS system to power a separate low power circulator pump that continuously circulates between the seton HX an the Super Stor buffer tank HX. The UPS instantly kicks in when power is out , only lasts 45 minutes . Would be great to have a much higher output UPS .

http://www.costco.com/Browse/Product.aspx?Prodid=11234507&whse=BC&topnav;=&browse;=&lang=en-US

 

[webbie]

FYI, I don't think the GW is considered a "gasification" boiler, then again most others are not true gasifiers either.

I see they are starting to call it a gasifier, but do keep in mind that it differs greatly from the Hill, Jetstream and European designs.

We could stretch and call EVERY efficient wood burning stove a gasifier, because they burn a quantity of the smoke. But so does a bonfire. Anyway, I like the term downdraft better, with the GW probably being a high mass downdraft or something like that.

 

[sixroses]

When I bought my GW100 21/2 years ago, they didn't have a pop off on the system. I have had more than a couple of boil overs, always intersting to see that much water on the floor... I am investing in a battery back-up and inverter set up in the next couple of weeks. Power outages have been the biggest problem I have had with the boiler. The rest of the troubles stem from a meat cutter trying to be a plumber :lol: My system gets better with each upgrade to plumbing I make.
Steve
Just got done priceing battery inverter charger set up. 500.00 will get me going.

 

[SnowTraveler]

I have to think that with a battery system costing as much as $2100 to keep a loop active, wouldn't some want to consider
a standby generator (Generac, Kohler, etc) instead? This way you can run other loads in your home too. I just bought a 12 KW Kohler, propane, with ATS for $3k.

 

[antos_ketcham]

I have a GW 100 and have experienced one boiler over.

The only damage fortunately was a broken sight glass on the expansion tank (which I replaced with a hose clamp and piece of high temp flexible tubing - GW wanted 40 bucks to replace sight glass!) and my nerves. It was fairly strssful listening to the furnace bubble and rock and clang and watch the contents of the expansion tank belch out onto the floor. Good thing my unit is outdoors.

What was amazing was that I knew the bad weather was coming and I didn't add any wood to the unit since that morning. So it had been 14 or 15 hours since it was loaded when the power went down and it still got up to 240 and boiled over. Glad it wasn't fully loaded when that happened.

All that said, I had planned from the get go to get a standby LP generator to back up the system. We get frequent and sometimes long power outages up here in the hills.

I went with a 13kw Generac LP standby generator.

I have been quite happy with my GW 100. It smokes a lot less than my Central Boiler did and burns less wood.

Everything seems to be working great now.

Good luck.

Pete

 

[Grover59]

I think a man could easily build a battery backup with maybe one or two deep cycle batteries and an inverter. You would want the thing to turn on and take over automatically, and this is where it may get a little tricky. I am sure with the right type of relays and stuff it can be done a lot cheaper then what they have for a price. The UPS idea is a good one, just it may not last that long, but it will kick in automatically. Not sure why they want so much money for their backup system seems a little pricy to me. We don’t have that many power outages here where I am at but we did the other night, I have a gravity feed loop that I can open to dump the heat, it would be automatic however I have not completed the job.

Steve

 

[FishHawk 210CC]

The $2100 price seems pretty high especailly considering a generator option would be similarly priced. The vendor is Energyworks out of Liberty, Maine (soon to be changed to revisionenergy). I thought the boiler price was fairly high as well at $10,200 (just boiler).

I am leaning towards the woodgun as it appears to be a better boiler at a lower cost. I like the low exit flue gas temp and the high velocity heat exchanger on the unit. Still undecided on stainless vs. boiler plate.

 

[tigermaple]

You can get a battery back-up for two hundred bucks, I know cause I sell them. You can make your own also for less with a marine battery. Well worth the investment with a GW. I believe GW' is a true gasification furnace. It surely reaches very high temps and produces little smoke when run correctly.

 

[antos_ketcham]

Agreed on the GW being a clean burner when used properly. The key is burning well seasoned large rounds and using storage. I am missing the storage but am working on the wife to let me get a tank.

Pete

 

[DKerley]

Take a look at this link to see my setup. https://www.hearth.com/talk/threads/16331/

I have two dump zones, the first is set at 190 degrees and dumps the heat out to my shop should the greenwood get too hot, the other, is a baseboard loop that is above my greenwood which opens when the power goes out. The battery and inverter keep the circulation pump and damper on the Greenwood running. Additionally, I have the house wired for a generator back-up (still shopping for a used generator) so that I can keep it all together at 40 below. The automatic switching to the battery is required to prevent the GW from getting too hot, it doesn't take very long for the heat to build up inside the unit.

Speaking of heat retention, I have had my boiler shutdown ie no fire for 6 hours while cleaning, If I shut off the circulation pump and did not open the dump zone, the boiler temp would still rocket up. It takes time for the first 150 deg. but then she quickly rises. This says a lot of very positive things about the refractory's ability to store heat.

Cheers,

 

[Grover59]

You can get a battery back-up for two hundred bucks, I know cause I sell them. You can make your own also for less with a marine battery. Well worth the investment with a GW. I believe GW' is a true gasification furnace. It surely reaches very high temps and produces little smoke when run correctly.

What does your backup unit consist of ? It sounds pretty reasonalble even at 200 bucks.

Steve

 

[sparke]

http://i126.photobucket.com/albums/p83/sparkie68/IMG_0001.jpg