Outdoor Wood Furnace Info

All-Purpose OWF Discussions => General Outdoor Furnace Discussion => Topic started by: BigAlsc on December 25, 2013, 10:23:52 AM

Title: ncb 175 clunking sound
Post by: BigAlsc on December 25, 2013, 10:23:52 AM

Merry Christmas everyone. Yesterday I noticed the stack that comes down into the burn chamber had a 2.5" hole burned through it about 1" from the bottom. Realized the bottom so called grate was slid toward the door and the gap in the back was causing the forced draft to get that area really hot. Slid the grate all the way back and now it flames a lot at the door and what sounds like really large boiling bubbles in the tank. Also had some boil over after that but still water in yhr overflow pipe. A lot of hard thumping noises that never had before. Would this just be water boiling for some reason? Aquastat set at 185 with a diff of 8.

Title: Re: ncb 175 clunking sound
Post by: hondaracer2oo4 on December 25, 2013, 11:22:42 AM

All of what your describing sounds like boiling water. Are you running coal by any chance?

Title: Re: ncb 175 clunking sound
Post by: BigAlsc on December 25, 2013, 11:56:54 AM

No, just wood and it was less than 1/2 full of wood/coals. Checked aquastat it was at 190 so I turned it down a little.

Title: Re: ncb 175 clunking sound
Post by: RSI on December 25, 2013, 12:40:19 PM

Is it the newer model with the water jacket around the chimney?

Do you have any idea how long it has been slid forward? If it has been a long time, a lot of the air might have been going straight up the chimney. If that was happening it would have needed the air opened way up to get enough for a normal burn. I would start by adjusting the air and see if it stops the noise.

Title: Re: ncb 175 clunking sound
Post by: BigAlsc on December 25, 2013, 01:34:22 PM

Not sure how long it's been slid forward but I did notice it burning towards the back a lot for a couple of days now. Its a 2008 and yes the waterjacket is around the chimney pipe.  I racked the coals around to try and make sure the other slots aren't plugged up so it will burn more even. It just doesn't make sense that the boiling sound seems to be up front near the door even though there was a lot of open chamber to be absorbing the heat.

Title: Re: ncb 175 clunking sound
Post by: rick n kristi on December 29, 2013, 06:44:55 AM

My 325G does the same thing (boiling sound near the front door) when it's trying hard to recover from a big call for heat.

Title: Re: ncb 175 clunking sound
Post by: MD20/20 on December 29, 2013, 08:31:09 AM

My 325G does it as well.

Title: Re: ncb 175 clunking sound
Post by: Scott7m on December 29, 2013, 08:46:18 AM

Ive heard it before too

Title: Re: ncb 175 clunking sound
Post by: BigAlsc on December 29, 2013, 11:09:15 AM

I'm not sure what changed but it stopped doing it now. Pushed the grate all the way back and added a piece of angle to the front gap and getting more air/ burn in the middle slots.

Title: Re: ncb 175 clunking sound
Post by: victor6deep on December 29, 2013, 01:22:43 PM

If my circ pump is on low it will thump if not I don't get a water boil thump.