ᐅ Freestanding stove, room air-independent (sealed combustion system)
Created on: 2 Dec 2011 13:56
T
Tatze
Hello stove experts and experienced users,
We are scheduled to start with the foundation slab next week.
A question has come back to our minds that we considered some time ago and now need to clarify before we begin. We want to prepare everything during construction for the later installation of a wood stove. Since we are also installing a ventilation system, the stove must be room-air independent, meaning it should draw fresh air directly from outside rather than from the indoor air.
As far as we know, there are two solutions for this. One option is to install a pipe directly within the foundation slab that connects the stove to the outside. This is the solution for which we need to decide now how to address the “fresh air” question. The second option would be to install a chimney flue with two ducts—one for exhaust air and one for fresh air.
We have already heard some negative comments about both options. For instance, the chimney sweep told us that a pipe in the foundation slab might create a cold spot. On the other hand, some people pointed out that a two-duct chimney might cause problems if, under certain weather conditions, the exhaust air is drawn back inside through the fresh air openings. My father-in-law also suggested (although he is not familiar with the system) that there could be issues with fresh air supply through the chimney itself, as it seems unclear to him why fresh air should “sink” down into the stove. He thinks that might cause difficulties when lighting the fire. Additionally, the supply and exhaust pipe connecting the chimney and stove would have a 90-degree bend sideways in our layout.
To cut a long story short... have you had experience with either system (both positive and negative)? Can you also provide some information about costs? Does the 90-degree bend cause any problems?
Thanks in advance for your responses.
Best regards,
Tatze
We are scheduled to start with the foundation slab next week.
A question has come back to our minds that we considered some time ago and now need to clarify before we begin. We want to prepare everything during construction for the later installation of a wood stove. Since we are also installing a ventilation system, the stove must be room-air independent, meaning it should draw fresh air directly from outside rather than from the indoor air.
As far as we know, there are two solutions for this. One option is to install a pipe directly within the foundation slab that connects the stove to the outside. This is the solution for which we need to decide now how to address the “fresh air” question. The second option would be to install a chimney flue with two ducts—one for exhaust air and one for fresh air.
We have already heard some negative comments about both options. For instance, the chimney sweep told us that a pipe in the foundation slab might create a cold spot. On the other hand, some people pointed out that a two-duct chimney might cause problems if, under certain weather conditions, the exhaust air is drawn back inside through the fresh air openings. My father-in-law also suggested (although he is not familiar with the system) that there could be issues with fresh air supply through the chimney itself, as it seems unclear to him why fresh air should “sink” down into the stove. He thinks that might cause difficulties when lighting the fire. Additionally, the supply and exhaust pipe connecting the chimney and stove would have a 90-degree bend sideways in our layout.
To cut a long story short... have you had experience with either system (both positive and negative)? Can you also provide some information about costs? Does the 90-degree bend cause any problems?
Thanks in advance for your responses.
Best regards,
Tatze
T
toxicmolotof17 Nov 2016 11:15The underground drain pipe is not UV-resistant and is not suitable for stove air supply because it is not fireproof. The first issue will eventually damage the pipe, and the second could (or should) concern the local chimney inspector.
Two other things you should also consider.
The problem with the 90° elbow is that condensate can collect in the trap. This is also not ideal.
Two other things you should also consider.
The problem with the 90° elbow is that condensate can collect in the trap. This is also not ideal.
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Knallkörper17 Nov 2016 14:12I would buy a stove with water injection.
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garfunkel17 Nov 2016 16:45The comment should be in a different thread
toxicmolotow schrieb:
The KG pipe is not UV-resistant and is not suitable as stove air supply duct because it is not fireproof. The former will eventually damage the pipe, and the latter might (or should) raise concerns with the local chimney inspector.... that’s a good tip! What do you recommend? If you know this in advance, you can have the right pipe/material installed.
T
toxicmolotof17 Nov 2016 21:30There are officially approved metal supply pipes that also have DIBt certification. This way, you are on the absolutely safe side. Stove installers and possibly plumbers can help with this.
If you want something improvised... PVC pipes (HT pipes) are at least UV-resistant, but they are not fireproof. We solved the last section through the wall with PVC pipes (HT pipes), and the rest was done by the plumbing company using a metal pipe.
If you want something improvised... PVC pipes (HT pipes) are at least UV-resistant, but they are not fireproof. We solved the last section through the wall with PVC pipes (HT pipes), and the rest was done by the plumbing company using a metal pipe.