need advice, feed PVC down chimney flue
Looking for advice on how to relocate condensing boiler intake and exhaust piping up the chimney of our old house.
Here’s the situation. 45 y.o. boiler was replaced a couple of years ago with Weil-McLain Ultra and an indirect fired water heater. Chimney flue was bricked up in the basement and boiler was fed and vented via 2x 4†PVC out a nearby window well. Problem is the big white uglies poke up along the driveway at the front of the house, near the front door. It’s the first thing you see coming up the driveway and it’s unsightly, a fact my wife reminds me of fairly regularly. Distance from nearby windows and doors is far enough to be within safety specs according to the boiler venting instructions, but not by much.
I’d like to re-route the venting back up the chimney flue. The flue is a straight shot 12â€x12†and I’ve verified that 2x 4†PVC will fit in, along with the 90 degree elbows at the base (I unbricked the opening in the basement and used a couple of 2’ sections). The problem is that the distance from the flue opening in the basement to top of chimney is about 35-40 feet, and the PVC will have to be fed in from the top, gluing sequential 10 foot sections together as it is lowered down the flue while being supported by a sling. There is access to the top of the chimney by climbing up a roof valley, which can be accessed from a window that opens onto the flat roof of a sunroom below, but I don’t feel comfortable climbing around on the roof and I certainly don’t have any safety equipment to prevent a fall, which is a distinct possibility if I’m up there trying to hold on to the chimney with one hand and wrangling 10 feet of 4†schedule 40 with the other.
So here’s my question. The difficult part of the install is to get the 40 feet of 4†PVC fed down the chimney flue. How can I do this? Is this a job for a roofer, chimney sweep, mason, plumber, or just a couple of handymen? Should I just try to rent a HiLift for half a day (I have no way of transporting it – do they deliver? Is this economical?) Once the PVCs are in place I can hire a heating company to make the short connection to the nearby boiler in the basement. Any suggestions? Thanks.
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I did that for a temporary plumbing vent, fed the PVC down in sections, clamped it, glued on a coupling and another section and kept going. This was about 40' as well of pipe.
I made a clamp out of a 2x6" (I was only feed 2" pipe, so you'd have to upsize obv.) by cutting a 2 1/2" hole in it, then cutting one side out of the hole, so that I could slip the clamp around the pipe. Then I just used a couple of shims on either side of the pipe to wedge it in place while I glued up the next section. Might be more difficult with 4" pipe, but my biggest problem was having 10' of 2" pipe waving around in the wind, 4" should be far stiffer.
Dunno about who to hire, but it is easily doable.
Z
You could paint the PVC--not sure if that would help if it is so obvious.
Thought about painting, cladding with copper (upscale look), and building various hutches, screens, dog houses to hide it. In the end, though, it won't fit in with the rest of the house and will still be belching steam/exhaust near the doorway. Even though Sch. 40 PVC is not that cheap anymore, I still figured I could run it up the flue for about $150-220 in materials, which is probably within a factor of 2 of the cost of building an attractive hutch, assuming the hutch I built was actually attractive.
Make a plan to deal with all the condensation that will be inside that pipe. Sizable I'd suspect.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
"If Brains was lard, you couldn't grease much of a pan"Jed Clampitt
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I see a few potential prob. with your idea:
1: How are you going to permanently support the PVC; 40ft. can be quite heavy
2: When you glue it up any weight before the glue sets may break the joint apart
3: Like other post said you need to address the condensate; I do have an answer for that, add tees to bottom of the line and install boiler drains. Sorry I'm not more help
"If all else fails, read the directions"
The furnace itself is equipped to handle the condensate.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Good thing it ain't me doing it. I don't even HAVE central heat..LOLSpheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
"If Brains was lard, you couldn't grease much of a pan"Jed Clampitt
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1: How are you going to permanently support the PVC; 40ft. can be quite heavyThe entrance to the flue in the basement is about 5 feet up in the brick chimney stack and is apparently solid below the flue entrance. I was planning that the 90 deg. elbows at the bottom would rest on this masonry base.2: When you glue it up any weight before the glue sets may break the joint apartAbsolutely right. That's why I was planning to support the pvc with a rope or sling fastened to the bottom of the stack, and then lowering it down as sections of pipe are added. This way there is no upward force on the joints.3: Like other post said you need to address the condensate; I do have an answer for that, add tees to bottom of the line and install boiler drains. Sorry I'm not more helpCurrently what condensate that is produced goes out a drain at the bottom of the boiler. However, that's for a current vent pipe of about 15 feet. Extending to 40+ feet will result in more condensate running back down the pipe. However, the boiler specs say that the vent pipe can be as long as 100 feet, so my plan still seems to be within acceptable limits. Thanks for the suggestions.
"3: Like other post said you need to address the condensate; I do have an answer for that, add tees to bottom of the line and install boiler drains. Sorry I'm not more help"
Well, that may be AN answer, but it ain't the RIGHT answer! LOL.
As someone else said, the furnace itself will handle the condensation. The pipe should be sloped so any condensation runs to the boiler's condensate drain which, if installed properly, drains to a pump and/or a drain.
As for support for the pipe, it's not likely that you'll *need* it, since the pipe will be vertical, but if you want it, you can fill the cavity with a mixture of vermiculite and portland cement (aka "ChimMix" -- one pre-mixed brand) and pour a cap around the pipes at the top.
As for who can do this, pretty much anybody who ain't afeared of heights. But you may want to check with your local heating contractors -- they do this all the time (or hire it out), and will know how to make sure the job's done correctly.
That said, as another poster pointed out, if you want to DIY, it's pretty easy to build a small platform in the "V" behind the chimney and work from there comfortably. Especially if you cut the pipe down to 5 footers. Oh yeah, and if you're lowering the pipe down on a rope sling, don't forget to plan how you're gonna get the rope off the pipe and out of the chimney.Mike HennessyPittsburgh, PAEverything fits, until you put glue on it.
I've heard of running tractor radiator hose down the chimney, for condensing furnace flues.
But keep in mind that whatever you do has to be within the furnace manufacturer's specs.
1. Do you have a combustion air intake also? If so, read the instructions. They probably require that the intake and exhaust be close together. That is important to prevent back pressure in the wrong place. (In fact, read the instructions about exhaust installation in any case.)
2. The instructions will tell you how long a run you can have. It depends on the size of your pipe. Follow those recommendations (translation: "requirements") exactly.
3. The instructions will give you guidance on how to slant the piping. Be sure to follow it carefully. That is what controls the condensation and potential freezups.
4. PVC pipe does NOT like to be unsupported for long lengths. Obviously vertical runs are less problemmatic than horizontal, but still........
1. Do you have a combustion air intake also? If so, read the instructions. They probably require that the intake and exhaust be close together. That is important to prevent back pressure in the wrong place. (In fact, read the instructions about exhaust installation in any case.)Yes, I will have to make 2 runs, one for the intake and one for the exhaust, and I realize that they have to terminate at approximately the same vertical in order to balance the air pressure.2. The instructions will tell you how long a run you can have. It depends on the size of your pipe. Follow those recommendations (translation: "requirements") exactly.Yup. 100 feet max, minus corrections for elbows. My planned 40+ feet of running length plus 2x90 deg, 2x 45 deg bends is within these specs.3. The instructions will give you guidance on how to slant the piping. Be sure to follow it carefully. That is what controls the condensation and potential freezups.Good point. Thanks.4. PVC pipe does NOT like to be unsupported for long lengths. Obviously vertical runs are less problemmatic than horizontal, but still........I was hoping that the vertical run would rest on the base of the flue opening, thus supporting the bulk of the weight. Thanks for the suggestions.Any insight into who to hire or how to actually get up there to feed the pvc down the chimney, anyone? Assuming I didn't die in the process, my wife would probably kill me when I came down if I tried to wrangle the pvc in myself!
I have used a manlift for similar jobs on the chimney. They are fantastic in ease of use, and my local dealer will deliver to the house if I needed that. Jusst measure carefully so that you know the height and reach that you need: one that is 2 feet short is a real annoyance!
Also, cutting the pipe to 5-foot lengths makes it a WHOLE lot easier to wave around over your head and get inserted into the coupling!
Bob
You know, it doesn't HAVE to be PVC. Your manual will tell you the acceptable materials. Perhaps there is something lighter (albeit certainly more expensive!).That said, the suggestion made above about cutting the PVC in half is really good. Be sure to use primer on all your joints.Finally, if I correctly interpreted your idea, you were going to support the BOTTOM of the stack with some sort of sling, and lower THAT using a rope. Check how heavy the stack will be, and if it is not too heavy to manage, it might be a pretty good idea. Be sure to put the ell on first and have the base support ready.Also, pipe has some sort of marker, usually the name, on one side. Keep that marker aligned with the bend opening, and you will have the unit pointing in the right direction when you reach the bottom.Finally, you might want to see if you can put some sort of cap on the top to keep out critters and snow.
Be aware that some high-efficiency appliance require that the intake and exhaust be in the same "pressure zone" which I believe would require both your intake and exhaust be run up the chimney
IF the manufacturer specs say that
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The suggestion has already been made that you cut pipe into 5-foot lengths for easier handling.
I'd suggest that you make a standing platform. A pair of 2x4's on edge and long enough to extend from the flat roof to the chimney. Build a platform attached at the point where the chimney is and angled to make it horizontal.
If the pitch is pretty steep, you could extend your "tracks" above the chimney on both sides and screw a short 2x across them so the chimney acts as a dead man.
Or get a chicken ladder and let the chickens do it.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
Sounds like you've got everything covered as regards compliance with the manufacturer's instructions and support of the PVC, condensate drainage, etc.
The remaining problem is that you'd really prefer to have someone else do the lowering of PVC from the rooftop.
Heating contractors do this all the time. It's very common to use a masonry chimney as a chase for PVC, and it's also common to have the length that you do to reach from the basement to the 2nd story roof.
Not only boilers, but also condensing (high-efficiency) furnaces use the same 2-pipe system for intake/exhaust. My point is that heating contractors are in the business of dealing situations just like yours.
Make sure anybody you hire can prove they have current liability insurance and workman's comp. in case of a fall.
They should also finish the top with a shoe box type lid of galvanized sheet metal that will have 2 holes sized for the PVC. This will not only keep the weather out, but will help reduce condensation by retaining warmth in the chimney. (Not that condenstion is a no-no--your boiler is designed to condense water vapor from the flue gases; that's a result of the high efficiency.)
Thanks everyone for considering my problem and offering suggestions. Cutting the pipe into 5' sections seems like a good idea - couplers are pretty cheap and gluing pvc is well within my skill set.I did call one heating contractor for a quote - he came back with $1700 for the job, which I thought was excessive considering it's probably a one day job for 2 guys. I will look into renting a man lift - it looks like an electric scissor lift would make it up high enough - but I'm not sure about the cost. Probably less than $1700 though! I'll also contact some other heating contractors. My guess is that the first company just didn't want the job.
$1700 sounds way high to me, too. I'm no heating contractor, but the ones I know would do this for under $500. (Labor only.)
Wish you were my neighbor--I'd do it for $300 and a six-pack. (But not Bud Lite--the cheapest I could go would be Sam Adams Pale Ale.)
Presumably the beer would be delivered *after* you came down from the roof. I was looking for a price that was about 2-3x the cost of the materials.