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Newbie chimney questions
bri86
Member Posts: 11
Hi all,
The home I purchased recently has a chimney that's in poor condition above the roof line. It's being used to exhaust the gas boiler (recent model LoganoUS/CA GC 144II) and Rheem gas water heater for the house. We're gotten quotes for tuck pointing that range from $ to $. I don't know the condition of the pipes within the chimney.
I'm wondering if it makes sense to use a "power vent" (Tjernlund HS1) to side vent the exhaust instead of going through the chimney? It's appealing to me to be able to seal the roof, and to avoid possible chimney expenses in the future. I have one quote to install a power vent (that would handle both the boiler and water heater) for about $. Here are some questions I have:
a) how reliable are Tjernlund power venters?
b) If there is an electrical outage, that's problematic for a power venter, right?
c) How much more worrisome is it to have the exhaust gasses being exhausted near ground level (as opposed to chimney height)?
d) Does $ to install a power venter seem reasonable?
e) Could I install a separate chimney running alongside the house to 1) avoid using the current chimney and 2) avoid a power venter?
f) Rheem, the company that produced my water heater, said that side venting is not possible. Is it common for companies to claim that side venting is not possible when it actually is possible? Note: HVAC guys who installed the boiler claim it's no problem, and I don't know who do believe.
g) besides tuck pointing, how much maintenance should I expect for this chimney?
All your advice is much appreciated.
The home I purchased recently has a chimney that's in poor condition above the roof line. It's being used to exhaust the gas boiler (recent model LoganoUS/CA GC 144II) and Rheem gas water heater for the house. We're gotten quotes for tuck pointing that range from $ to $. I don't know the condition of the pipes within the chimney.
I'm wondering if it makes sense to use a "power vent" (Tjernlund HS1) to side vent the exhaust instead of going through the chimney? It's appealing to me to be able to seal the roof, and to avoid possible chimney expenses in the future. I have one quote to install a power vent (that would handle both the boiler and water heater) for about $. Here are some questions I have:
a) how reliable are Tjernlund power venters?
b) If there is an electrical outage, that's problematic for a power venter, right?
c) How much more worrisome is it to have the exhaust gasses being exhausted near ground level (as opposed to chimney height)?
d) Does $ to install a power venter seem reasonable?
e) Could I install a separate chimney running alongside the house to 1) avoid using the current chimney and 2) avoid a power venter?
f) Rheem, the company that produced my water heater, said that side venting is not possible. Is it common for companies to claim that side venting is not possible when it actually is possible? Note: HVAC guys who installed the boiler claim it's no problem, and I don't know who do believe.
g) besides tuck pointing, how much maintenance should I expect for this chimney?
All your advice is much appreciated.
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Comments
First, sounds very expensive just to point the chimney, unless it requires a lot of set-up-scaffolding, etc.
Just pointing the chimney doesn't tell anyone about the condition of the entire chimney. Only a Level II inspection by a certified chimney company can tell you that.
The easiest/best solution, depending on entire chimney integrity would be to have the chimney repaired above the roof line, drop a stainless steel liner down there properly sized to handle both appliances.
If you have a basic atmospheric gas water heater, it can't be direct vented. If a manufacturer had a product that could be direct vented, they would definitely let you know. Don't listen to any putz who wants to violate code because they "do it all the time". Manufacturer trumps all and if you drop dead from CO poisoning, that guy will be nowhere to be found.
Both can be power vented, and the price is probably right, depending on what's involved in making the holes, hooking it up, the additional controls, etc.
But I really would only power vent both of them as an absolute last resort.
Sorry, I didn't mean to imply that the HVAC folks said it could be direct vented. They said that it could be power vented.
I don't think that the scaffolding would be especially difficult. The roof is relatively steep though (roughly 12/12). Chimney is roughly 4' or 5' tall above the roof line.
If you rebuild the chimney then maintain it, keep the cap and mortar in good shape, the future repairs should be minor. Getting in to a condition where it needs to be rebuilt results from neglect or improper repair.
This would be a fair amount of work. It seems like there is an energy efficiency benefit in closing up the chimney.
How crazy is this "new chimney" idea - if it's even possible?
Ugly? Absolutely.
You can vent thru the roof. Take the chimney down below the roof line, patch roof, run liner/piping with proper thru the roof termination.
Power venting = maintaining and repairing over the life of the boiler.
My experience with mechanical venting is they last about 5 years before the motor fails or the unit rusts away. I use stainless steel models for both oil and gas venting and in my area, they still corrode away. The longest-lasting one I had installed before repair or replacement was necessary was 8 years. We are surrounded by saltwater (on 3 sides) within 2 miles of every location in my county. You may get better performance if you are away from the coast.
Retired HVAC Contractor from So. Jersey Shore.
Cleaned & services first oil heating system at age 16
Specialized in Oil Heat and Hydronics where the competition did Gas Warm Air
If you make an expensive repair and the same problem happens, What will you check next?
Do y'all have opinions on chimney b-vents? I'm considering installing that just below the roofline. What are the pros/cons of that vs a traditional chimney?
Do you have access in the attic to the chimney ?
On one job I have had the bricks removed from above the roof and below the roof down to about a foot above the ceiling.
Then from the attic able to connect and lower long lengths of B vent down to the basement. There is a great support/fire stop for B vent that would hold the vent up.
Then build upward thru the peak as per code for height.
The roof hole will have to decreased in size, singles and the final flashing would secure the vent vertically.
No mason needed. Just carpenter/roofer and HVAC vent installer.
This limited the time on a steep roof. Easier to assemble the B vent in the attic.
It sounds like you're talking b-vent all the way to the basement, which is not what I was imagining. I was imagining having it start in the attic (ie the existing would connect to the b-vent there). But perhaps that's either impossible or unwise?
If it's simple, can anyone share how high the b-vent must rise above the roof line per code? If it's complicated and/or depends on local authorities, I totally understand and will do that homework.
if you open it and clean it out then with a mirror do you see blue sky straight up the inside?
If you want B vent it needs to be continuous B vent from the basement to the roof cap. There is probably not any pipe inside your brick chimney. The mirror inspection would tell you that.
An old school rule of thumb was that chimney had to be 24" above anything within 10' radius. That explains why your brick chimney sticks up 5'. Local current codes would dictate that height.
Is there a good corner/closet or wall location that you could get a straight shot from the basement up thru near to the peak of the roof. It could be boxed in and then finished to match the decor.
Then you would have minimum steel pipe showing.
Or take the brick down to almost the attic floor, drop B vent pipe to the basement opening. Then offset with elbows in the attic to get near the peak.
We took an old chimney down. Full 2 story with steep roof line.
On the roof the bricks were dropped down inside the chimney and a helper pulled them out of the clean out a couple at a time.
Coordination and communication between each end to avoid smashed hands.
In your case then the old hole in the roof would allow straight length to be lowered into the basement
The old form I have is from 2006 and poorly written.....confusion.
There must be something out there that gives clearer info.
You still have to go by local codes though.
Or you could penetrate the roof at the peak and have 24” of pipe exposed.
Or one foot below the peak and have 36” of pipe.
A chase looks kinda' like a closet or elevator enclosure when framed in. However, it can also be made of masonry, pipes, ducting- almost anything that has a flame spread rating of 500 or less and is fully enclosed. It's a conduit for a mechanical system.
You can take a masonry chimney's flue, install a listed venting system in it such as B-vent and the brick flue becomes a chase- a housing. It's like eating lettuce- nothing to it.
HTH
https://www.hartandcooley.com/assets/files/o4/150952-typebgasvent-130116.pdf
Retired HVAC Contractor from So. Jersey Shore.
Cleaned & services first oil heating system at age 16
Specialized in Oil Heat and Hydronics where the competition did Gas Warm Air
If you make an expensive repair and the same problem happens, What will you check next?
The expense and grief of the supports would be more than offsetting with 45 degree elbows in the attic.....then you need only the 3' or less pipe showing.
IMO, the 10-12' pipe is necessary only if you are within 10 of the slope of the roof.....such as your brick chimney is now.
Yesterday I learned that there's a flexible b-vent (previously I thought it was always rigid). Furthermore, many companies make kits. For example, Menards has this "Amerivent® 5" x 35' B-Vent Flexible Chimney Re-Liner Kit".
Could something like this work? Does anyone have experience with these sorts of kits? I would need rigid b-vent above the roofline, so I'm not sure if this flexible version could be connected directly to a rigid version in my attic. All thoughts very appreciated!
If you repaired your bricks structurally above the roof then the liner would be an option. As the picture shows there is a plate to cover the chimney and then a B vent type cap for the top.
This system is such that it needs to be continuous from basement to roof cap, just like solid B vent.
Solid B vent is a double walled assembly that has aluminum for the inside pipe, this conducts heat well and induces a draft up the pipe. Then the outside pipe is galvanized steel for strength and weather resistance. There is a 1/4" air gap between the pipes that keeps the outer pipe from getting too hot. It still needs 1" clearance from combustibles. Once you start with the B vent in the basement it needs to be continuous thru the roof.
The flex liner relies upon the brick chimney for the fire resistance to protect the structure.
If you go to a box store and look at B vent of any brand you can see the construction.