|
Post by woodrascal on May 30, 2018 7:47:19 GMT -8
When I built my 5" Batch Box combined Masonry/Water heater last December I incorporated a cast iron access door near the base of the brick bell. The purpose of the door was to allow access to the original brick chimney that I use for the BB exhaust, for inspection and sweeping. I also made provision to light a 'priming' fire at the base of the stack to start the draw in the system (if needed) after not using the BB for some time. Well, today is cold and wet in North Wales (UK) and I duly fired up the BB for the first time for several weeks to humour my Daughter who is revising for exams and is feeling the cold... Disaster!! I forgot to light a priming fire and the BB smoked the room out! I tried to light a priming fire (with the BB firebox still well alight) but the downward gasses and smoke put the newspaper out... Once doors and windows were open to clear the smoke and the fire in the BB was down to coals, I was able to light a priming fire and the BB is now working perfectly The moral of this story is - 1/ If using an old masonry chimney for your BB exhaust in cold, damp climates, it would be well worth building an inspection door into the bell near the base of the stack, so that you can light a priming fire to establish a draw if needed. 2/ If in doubt, light a priming fire...! Don't risk smoking the house out.
|
|
|
Post by Vortex on May 30, 2018 8:44:40 GMT -8
Why didn't you just build a bypass from the top of the brick bell into the chimney for priming?
|
|
|
Post by pinhead on May 30, 2018 12:20:51 GMT -8
A bell bypass would have been a much more effective way to get the gas moving the right direction. Even if the BB had started smoking-back, the bypass would quickly get it moving in the right direction.
|
|
|
Post by woodrascal on May 31, 2018 3:13:53 GMT -8
Thanks for the comments.
A bell bypass would have been nice but the chimney is made from huge pieces of stone that are almost impossible to cut and remove. To pierce an opening for a bypass there would have made the project unworkable.
The existing chimney had an opening for an open fire at its base so the most sensible option was to use this and build in an access door (which I had in stock) at the base of my brick bell. The added bonus of this door is that I can sweep and monitor the condition of the chimney - which would not be possible with an internal bell bypass.
|
|
|
Post by pinhead on Jun 4, 2018 9:48:53 GMT -8
Thanks for the comments. A bell bypass would have been nice but the chimney is made from huge pieces of stone that are almost impossible to cut and remove. To pierce an opening for a bypass there would have made the project unworkable. It likely wouldn't have been necessary to add another chimney entry; all that is required for a bypass to work is the gasses have to bypass the heat exchanger. Whether this is done by directly feeding into a higher portion of the chimney, or flowing through an internal path to the chimney is immaterial as long as heat isn't lost on the way.
|
|