Heating incoming outside air

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.

iceguy4

Minister of Fire
Nov 16, 2011
1,039
Upstate, NY
What are your thoughts? Is it worth the hassle? anyone uning the selkirk system?
Thanks in advance for your time
 
I'm assuming you mean heating the air going to your stove? Are you having problems with icing of your OAK on the inside? There was a post a couple weeks ago by someone with that issue. Was that you?
 
I'm assuming you mean heating the air going to your stove? Are you having problems with icing of your OAK on the inside? There was a post a couple weeks ago by someone with that issue. Was that you?
No. but I did rig a set up like the selkerk system. I have no way to measure its
effectiveness...
 
My new setup is pulling air from inside the chimney. So it should temper my intake air. That was really my best option anyway for my insert
 
I have wondered the same thing. I have been checking my stove with IR gun all season. During the recent cold snap we had I disconnected the OAK.
The outside air was in the single digits. I check the stove in 4 locations (4 corners at the door). Without the OAK inhaling the frigid air the stove
temp went up at each corner as did the temp on the vent pipe. Preheating the combustion air must be good thing. I have also heard on here
many explainations of what temperature combustion occurs at and that the incoming air temp does not matter. However I think its fair to say that all the air
pulled through your stove is not exclusively used for combustion.
 
I have wondered the same thing. I have been checking my stove with IR gun all season. During the recent cold snap we had I disconnected the OAK.
The outside air was in the single digits. I check the stove in 4 locations (4 corners at the door). Without the OAK inhaling the frigid air the stove
temp went up at each corner as did the temp on the vent pipe. Preheating the combustion air must be good thing. I have also heard on here
many explainations of what temperature combustion occurs at and that the incoming air temp does not matter. However I think its fair to say that all the air
pulled through your stove is not exclusively used for combustion.

My knowlage of oil burners and their set up has taught me air for the most part is 21% O2 (necessary for combustion) and 79% N (completely useless for combustion but needs to be heated just the same)
 
anyone using the selkirk system?

I have it installed on my Castile insert and my PB105 boiler. It works very well on the Castile. It leaves a little to be desired on the PB105. On the boiler, the vent cap and the last 3 feet of venting that are located above my roof, get a creosote build-up in them. The boiler will idle for quite a while sometimes and I think that the amount of fresh air that is drawn in, cools down the interior pipe too much causing the creosote formation. It takes a quite a bit of work in the spring to clean up this buildup.

Is there anything a person can burn in a pellet boiler during the season to help this build-up of creosote?
 
My knowlage of oil burners and their set up has taught me air for the most part is 21% O2 (necessary for combustion) and 79% N (completely useless for combustion but needs to be heated just the same)

Hello

Did you OAK up your boiler? You must do that too, if you do your pellet stove!
See my boiler pics with Carlin Air Boot!
https://www.hearth.com/talk/threads...-or-becket-burner-air-boot.52869/#post-664807

The Boiler OAK is next to the Central Vac. Heck the Vacuum is Also vented outside! No sense getting all that dust that the filters do no catch blowing all over the place! ! ! !
 
Hello

Did you OAK up your boiler? You must do that too, if you do your pellet stove!
See my boiler pics with Carlin Air Boot!
https://www.hearth.com/talk/threads...-or-becket-burner-air-boot.52869/#post-664807

The Boiler OAK is next to the Central Vac. Heck the Vacuum is Also vented outside! No sense getting all that dust that the filters do no catch blowing all over the place! ! ! !

I would agree with you Don...if my oil boiler came on...it dosent...as for my central vacuum...never thought of that. Now thats gonna be tricky. Heading to shop right now...if I take hair dryer hose...rig it to ...I'll figure something out...pic's to follow
 
I would agree with you Don...if my oil boiler came on...it dosent...as for my central vacuum...never thought of that. Now thats gonna be tricky. Heading to shop right now...if I take hair dryer hose...rig it to ...I'll figure something out...pic's to follow

Hey, that is an idea! The negative pressure in the bathroom created by the exhaust fan in the ceiling could very well be offset with an OAK on the hair dryer!

Using a hair dryer may be a great idea to warm up that OAK air!! Good idea!

How about this HotPod? Should do the trick!
http://www.heatersplus.com/hotpod.html

  • Do you turn up your thermostat in the morning for the whole house…just to have a warm bathroom?
  • When you leave home for vacation during the winter months, do you worry about “what if” the furnace fails?
  • Do you want to keep the baby’s room at a warmer temperature, and the rest of the house cooler?
  • Now you can have a warm bathroom, a back-up system for the furnace and a consistently warm baby’s room.
 
Preheating combustion air in automobiles and commercial power plants are common practices today. This increases the efficiency of fuel consumption and a reduction in pollution. The disadvantages is that in automobiles you no longer have the densest air possible to generate maximum horsepower. However with the advancements in technology does that really matter? Unless you are racing or need this extra power with a reduction of fuel efficiency, no it does not. Any residential high-efficiency boiler/ furnaces, combustion air is irrelevant because most of the heat is extracted for heating your home. This Is why some systems have PVC piping. But if you use a lesser efficient appliance, preheating combustion air will increase efficiency.

Pellet stoves and boilers still require stainless steel piping because the output temperature of the exhaust is still hot enough to melt PVC. Therefore using the exhaust from the pellet appliance to preheat combustion air will reduce fuel consumption. Because you are increasing the temperature of the cold air, less energy is used to bring it up to combustion temperatures. Now some people may claim that the pellet stove works better, without preheating the air. However this is not true, though the flame may perform better, it is actually not burning at maximum efficiency. Again this is because it takes more BTUs to rise the combustion air to combustion temperatures, therefore consumption of wood pellets is actually increased.

If you are having problems with condensation and icing it would be advisable to insulate your piping with appropriate fiberglass insulation that has an outer foil wrap. This will help with keeping the moisture from making contact with the venting. Now some systems may condense more often than others on several reasons. First is the length of the venting may be too short therefore not giving the air enough time to heat. Second it could be that no matter how much length of venting there is to heat the combustion air, the outside combustion air could be very cold. However the air still being preheated. Third, some pellet appliances can be more efficient than others therefore it could be a more common problem with the more efficient stoves. With a lesser amount of BTUs leaving through the vent, there is less to preheat the air. Last it also could depend on what setting you using and having a combination of the above.

There is no advantage in pulling room air for you heating appliance. Again you are losing efficiency using more energy to make up the difference lost in preheating the combustion air. As a matter of fact this could be unhealthy with airtight homes as it produces a negative pressure. Therefore the combustion air should be drawn from the outside. One other thing there is a difference between actually preheating air and a system like the one above to compensate for negative air pressure in the home. Preheating combustion air requires something like what Selkirk's direct temp sells where combustion air is directed around the exhaust vent as a single unit.
 
Using anything but natural convection to preheat the air wouldn't be worth it IMHO. Why pay extra using electric heating elements that cost $$$ to use?
 
  • Like
Reactions: StihlHead
Using anything but natural convection to preheat the air would be worth it IMHO. Why pay extra using electric heating elements that cost $$$ to use?
In a retention flame oil burner, It is actually has to do with the fuel being too cold, what you get is called Puff back. The igniter is not hot enough to instantly lite the fuel therefore there is a delayed action before it does. Makes a loud bang and scares the crap out of yah. For any heating appliance there is no advantage in using an external preheating source for combustion air. Unless it is difficult for the fuel to light. When I had the oil burner myself it was cheaper to use an additive, nozzle line preheater, and number two home heating oil instead of the more expensive kerosene or mobile home blend.
 
Pellet stoves and boilers still require stainless steel piping because the output temperature of the exhaust is still hot enough to melt PVC. Therefore using the exhaust from the pellet appliance to preheat combustion air will reduce fuel consumption. Because you are increasing the temperature of the cold air, less energy is used to bring it up to combustion temperatures. Now some people may claim that the pellet stove works better, without preheating the air. However this is not true, though the flame may perform better, it is actually not burning at maximum efficiency. Again this is because it takes more BTUs to rise the combustion air to combustion temperatures, therefore consumption of wood pellets is actually increased..

Could you provide a reference for that statement?.
 
Could you provide a reference for that statement?.

content___media_external_images_media_36_zpsa397af4e.jpg
 
I still won't pay to heat my incoming air. I would possibly use a multi-pass heat exchanger or something. No way I'd bother using electric heating elements.

Sounds like using the selkirk system might be worth the extra cash.
 
If you think about it, the up-front cost of the "air heater" coupled with the expense of the electricity.....If you need more heat, why not just spend a little extra on your pellets and buy great pellets? Penny wise and dollar foolish?
 
How did we get to paying to pre-heat the outside with electricity...was it my comment
.if I take hair dryer hose...rig it to
That was a joke about rigging my central vacuum with an OAK ...I'm so cheap I can hardly pay attention
 
  • Like
Reactions: DexterDay
The Selkirk system would he somewhat beneficial. But a Very long run, especially external/outisde, will cause to much cooling of the exhaust gases and will cause, well, you know what to build up (Not Good :()

When I replace the Quad (I know, I know, I did that last year) this year, I plan to use Selkirk DT. A simple 4ft vert inside, to 3 ft horizontal.

But i wouldn't pay to heat the air. I'm doing it for the added convienence, and mainly for the looks. It looks just like 6" stove pipe :)
 
  • Like
Reactions: mepellet
Guess I should go blow down my pellet stove...
 
I have it installed on my Castile insert and my PB105 boiler. It works very well on the Castile. It leaves a little to be desired on the PB105. On the boiler, the vent cap and the last 3 feet of venting that are located above my roof, get a creosote build-up in them. The boiler will idle for quite a while sometimes and I think that the amount of fresh air that is drawn in, cools down the interior pipe too much causing the creosote formation. It takes a quite a bit of work in the spring to clean up this buildup.

Is there anything a person can burn in a pellet boiler during the season to help this build-up of creosote?

Well, you can try this:
https://www.hearth.com/talk/threads/took-one-for-the-team-csl-pellet-stove-cleaner.101029/

However, from the Q&A on the CSL website: "Q) Can CSL be used in a pellet stove fireplace insert?
A) NO!! you cannot use the CSL in a pellet stove. Pellet stoves are intended to produce very few smokes. However, it requires regular visual inspections."

I assume that was written before they came out with the CSL pellets.
 
Well, you can try this:
https://www.hearth.com/talk/threads/took-one-for-the-team-csl-pellet-stove-cleaner.101029/

However, from the Q&A on the CSL website: "Q) Can CSL be used in a pellet stove fireplace insert?
A) NO!! you cannot use the CSL in a pellet stove. Pellet stoves are intended to produce very few smokes. However, it requires regular visual inspections."

I assume that was written before they came out with the CSL pellets.


I have it installed on my Castile insert and my PB105 boiler. It works very well on the Castile. It leaves a little to be desired on the PB105. On the boiler, the vent cap and the last 3 feet of venting that are located above my roof, get a creosote build-up in them. The boiler will idle for quite a while sometimes and I think that the amount of fresh air that is drawn in, cools down the interior pipe too much causing the creosote formation. It takes a quite a bit of work in the spring to clean up this buildup.

Is there anything a person can burn in a pellet boiler during the season to help this build-up of creosote?

It sounds like you need to once in a while run it on high some how for an hour or so . You could add a dump circuit like some boilers have since they do not have an igniter. They just keep running all the time. This is to keep the house from getting to hot. The other option is to install some kind of mechanical or electrical bypass on the combustion circuit to keep the vent gas warm enough. But somehow you should not be generating creosote at all, even on low temperatures.
 
Status
Not open for further replies.