Chimney top rebuild, Liner/Insert install, Data logging

HomeinPA · Feb 15, 2019

KPru said:
Well, the one side is for our natural gas furnace, so definitely wanted to leave that one. But the other side is for an open fireplace that has wood very near the opening. I capped that one off for a little better insulation, as opposed to taking it down which seems like a bit more of an undertaking.

If you're venting a natural gas appliance I'd look in to running a stainless liner down that one soon. Otherwise all that beautiful masonry work could get ruined over time from the condensation inside the flue.

Dmitry · Mar 29, 2019

KPru said:
Liner/Insert install

Remove damper and increase opening size

damper came out pretty easy, couple of cotter pins and a screw was all holding mine in. Rotated it to get it out

used an angle grinder to increase the size of the opening pretty generously so I'd know we could position the liner wherever it needs to go

also the opening at the top of the smoke chamber needed to be opened up slightly, as the liner passes through at maybe a 15 degree angle

both of these were through pretty thick steel, and being in a tough area to work, took a bit of time

View attachment 233253

Insert liner

purchased (1) 6" heavy flex 304L stainless liner: 25 foot length, .018" thick = $518: Woodland direct

purchased (1) 6" 24 gauge stainless flat top plate: 13"x18" = $45: Rockford Chimney Supply

purchased (1) 6" 24 gauge stainless flex top plate: 13"x18" = $45+$13 shipping: Fireside Chimney Supply

purchased (2) 2" thick rockwool mat (Roxul - 1200F capability): 24"x48" = $24: Amazon

tied rope around coiled flex liner and lifted onto roof

heavy flex was very easy to straighten out on roof with one person

fed the "down" end (crimped, "up" end was labeled) down the center flue

twisted it a couple times when it would hang up on a clay flue tile lip

need a second person to help guide it through the damper plate opening

has a good 1-2" of "accordion" stretch to it, so initially positioned it about an inch high

then pulled it back up around 4 feet, to slide an upside down Fireside top plate

I had cut out the corners and bent up the sides to make an insulation "bottom plate"

added slits to make the side finger seals flexible

also bent the tops of the sides in, so they wouldn't catch if I needed to pull it up

tightened the hose clamp to secure this "bottom plate", then slide the liner back down the 4 feet

next I cut 4 foot lengths of rockwool to a width a little shorter than the flue width

had a 2nd person hold up the liner while doing this

slid these down the gap between the flex liner and flue, resting on top of the "bottom plate"

packed these in to insulate the top of the liner and the flue cavity

then secured the Rockford top plate

this had to be trimmed to size, otherwise I might have gone with their premium version which is sloped

also I had some 18 gauge (.050" thick) 304 stainless sheet that I cut to match the top plate profile along with a 6.5" hole. I placed this underneath the top plate for extra rigidity with this support

lesson learned: In terms of meeting code, an insulated liner could help satisfy the clearance to combustible requirement if your chimney does not meet the minimum 2” (for interior chimney, 1” for exterior chimney). In terms of performance, insulated liners should improve draft, make it quicker to start fires cold and reduce heat escaping through masonry…especially on an exterior chimney. With the inside width of my clay flue being 6.5", a round insulated liner would have been difficult to impossible to slide down (without going the oval route). The 4 feet of rockwool insulation at the top might be overkill, but I'd have to imagine it will do something in keeping a better draft.

lesson learned: was very happy with the heavy flex liner: not too heavy to lift up, easy to straighten out, easy to feed from just the top without a pull cone/rope from the bottom, feels very thick/durable...suspect it will last for more fires/cleanings than a .006" thick easy flex liner (went with 304 stainless as it will just be for wood fires...vs more expensive 316 needed for some other fuels)

lesson learned: Rockford flat top plate for the same price as the Fireside flex top plate, but no shipping, appeared stiffer. Took out the calipers, checked around 5 or so different spots, and the Rockford plate measured .024"-.025", the Fireside plate was .021"-.022". Both maybe within spec for 24 gauge, but for this batch at least, enough to feel the difference.

View attachment 233254

Install block off plate

purchased (2) 18"x24" sheet of 24-gauge 304 stainless steel = $14 / each: Ebay

purchased (1) 24" Malco folding tool = $28: Amazon

purchased (1) 16oz can of Rutland 1200F stove paint = $27: Amazon

purchased (1) 7/8" x 8 foot Quadrafire stove door ceramic rope gasket = $22: Amazon

purchased (4) 3oz tubes of LavaLock high temp RTV silicone (500F continuous, 650F max) = $9 / tube: Amazon

purchased (2) 1" thick ceramic fiber insulation blankets (2300F capability): 24" wide x 8 feet long = $30 / blanket: Amazon

purchased (1) 75-pack of Tapcon 3/16" x 1-3/4" phillips flat head concrete anchors = $14: Home Depot

Main plate construction

cut piece of cardboard to match size of opening (above lintel, below damper opening)

used this as template for cutting 24 gauge sheet metal, notching corners, accounting for eventual bend height/radius

used 24" folding tool to bend up sides to less than 90 degrees (lets sides flex to match opening size)

oversized slot cut with aviation snips tracing semi-circle with 1.5" clearance side-to-side and 0.5" clearance fwd-to-back

main plate made in two pieces to create large overlapping area for sandwiching a sliding plate

painted with 3-4 coats of 1200F stove paint on each side, and cured in my grill. Probably not necessary, but thought was to possibly further protect the steel, maybe reduce top side radiation, nice aesthetics for something that will never be seen.

Sliding plate construction (unpainted)

sliding plate with smaller 1/4-3/8" clearance hole

7/8" rope gasket sized to still seal even if liner is not centered in hole

coiled rope gasket around liner 3 times, secured safety wire about both free ends, and then twisted it together to keep it tight around the liner

2 pieces of safety wire hooked around rope gasket to pull down and ensure seal after connecting insert

Assembly into fireplace

first wrapped around 2 feet of ceramic insulation around the bottom section of the liner above where the block off plate will go. Secured in place with safety wire.

stuffed area above damper opening with ceramic fiber insulation blankets

stacked 3 piece block off plate into place with flexing sidewalls holding it in place

match drilled (4) 1/4" holes through both main plates at both ends of overlapping section on both sides (drill access just to both sides of liner)

used hammer drill with 5/32" masonry bit to drill hole ~2" deep into brick

screwed in (4) 3/16"x1-3/4" Tapcons at these locations. Just 4 connections in these overlapping sections kept things pretty stiff. Thought was to allow wide direction a little more thermal growth freedom via flex of the bent side walls and not clamp down on the side walls there with anchors.

lastly, all seams between metal and masonry were caulked with high temp RTV silicone

useful link for making blockoff plates with examples: https://www.hearth.com/talk/wiki/why-damper-seal-is-needed-block-off-plate-install/

additional similar example not included above: https://www.hearth.com/talk/threads/sealing-block-off-plate-question.168661/#post-2264457

View attachment 233255 View attachment 233256

Prepare liner connection to insert

purchased (1) 6" x 15 degree fixed elbow for flex liner = $62: Rockford Chimney Supply

insert I ordered came with a 15 degree DuraVent elbow, but for a rigid liner, so had to scramble and order the Rockford part last minute. Quality welds, good design for making tight seals, and they got it over really fast

made small modification to add 2cutouts to elbow, allowing clearance with crossbar in insert's flue collar

tapped elbow down with hammer to get tight fit, match drilled holes and secured with screws

secured other end of elbow to bottom of flex liner, tightening hose clamp

all of these male/female connections are male facing down, so any condensates that are able to form and drip down remain within the exhaust path

View attachment 233257

Install insert

purchased (1) Quadrafire 4100i with large cast surround = $2,650 + $550: Yankee Fireplace - Middleton, MA

chose this model to allow for possible N-S loading, minimize how much sticks out into room and maximize firebox size that would fit in the existing open fireplace

also wanted a model with a blower to get the heat out, and was recommended by many to avoid catalytic inserts

goal is not to heat the whole house all winter, but to really get the family room/kitchen toasty on weekends when we're all there

placed 18"x24" sheet of left over 304 stainless at bottom of hearth, secured by small amount high temp silicone

this along with cardboard at front of hearth made sliding the insert back and forth easy for one person

installed leveling legs, swung baffle tube assembly down, removed baffle boards and insulation for liner connection access

slid insert back, pulled flue collar/liner down from inside insert, bolted in place

assembled surround and secured to insert (shown below without surround)

View attachment 233258

Trim/caulk liner top

back on roof, loosened top plate hose clamp and pulled liner up an inch or so for a light stretch

idea is that this "stretch" will be compressed when the liner heats up and wants to grow

used angle grinder to cut liner about 1" above the top plate cylinder

used high temp silicone to seal in between the liner OD and top plate cylinder

used general silicone to caulk around the edge of the top plate

View attachment 233259

Cap unused flue

house has another open fireplace that is unused, and should remain so (inadequate clearance to combustibles)

trimmed left over sheet metal to match flue perimeter, but offset in by ~1/4"

drilled (3) 1/4" clearance holes for eventual 1/4" threaded rod to pass through

used this as a template to make another similar sized sheet but with bent up sides, curled in at tops to make a bottom plate for insulation that can be easily installed down and removed up.

secured (3) 1/4" x 36" threaded rods through holes in bottom plate with washer/nut/jam nut on each side

fed bottom plate down ~3 ft through unused flue, temporarily held in place with clamps on tops of threaded rods

cut 3 foot lengths of 2" thick rockwool to width and lowered down in between threaded rods to rest on bottom plate

put bead of general silicone caulk around top of flue then pushed top plate down on top

secured threaded rods to top plate with washer/nut/jam nut on each side

View attachment 233260

Secure rain cap/cage

purchased (3) 6" and (1) 4" stainless hose clamp = ~$2 / each: Home Depot

previous wash (badly cracked) had cracks passing through each of the Tapcon holes drilled into the wash

to protect this new crown, decided to secure the rain cap to the (2) clay flue extensions

to try and protect the flues as well, 2 hose clamps were hooked in series to wrap around flue and through side of rain cap cage

larger flue has (2) 6" hose clamps, smaller flue has (1) 6" and (1) 4" hose clamp

tightened these down and rain cap isn't going anywhere, and clamp load seems pretty well distributed around the flues

View attachment 233261

Install metal shelf

purchased (1) black steel ledge: 60" wide x 5" deep x 2" tall = $89: Room & Board

purchased (1) 75 pack of black 3/16" x 1-1/4" WallDog phillips pan head screws = $15: Amazon

main purpose of this shelf is a heat shield to hopefully lower temperatures seen by the TV a little bit

we have short 7' ceilings, so this shelf ended up being at just over a 4' height (TV is wall mounted)

secured into mortar with (4) black WallDog screws after drilling 3/16" holes into mortar

for load bearing applications (like TV mount) I'll anchor to brick (and likely use a sleeve anchor), but for this I think mortar should be fine

used some left over lumber/shims/clamps to adjust and hold in place for drilling/securing

View attachment 233262

Install child gate

purchased (1) metal adjustable safety gate = $40: got 2nd hand locally, not sure of make details, but in great shape

3 children in house under 5, insert in high traffic area

secured to mortar with (2) WallDog screws on each side

1st burn

opened burn rate air control to high, opened startup air control as well

loaded (2) 16" splits N-S on sides of firebox and then ~10 crumpled newspapers in middle with some kindling above that

Ash, aged ~ 2 years, only tarp protection on top foot or so

took probably 3 or 4 more loads of kindling to catch splits, so a little smokey opening the door too much

start up air control closes after ~25 minutes, so I opened this one more time during the process

splits burned ~4 hours, could smell a strong stove paint curing smell

reloaded 4 smaller splits on top of hot coals with newspaper/kindling and fire started with little effort on my end at all

burned 6+ hours, put on blower for this and got some pretty good heat, room got to low/mid 70's, top of metal shelf under TV never got above 84 degrees

Future plans

still need to refine my fire skills a bit....starting cold, loading up for an overnight burn, not overfiring, thermometer purchase, etc.

in the spring, want to use some left over PVC to make a support structure for covering the stacked splits and figure out a good roofing material

right now, have just been using tarps to cover the top during spring/summer/fall, and to drape over everything in the winter

feel like I've got some room for improvement to get moisture content down

I'm looking at the same 304 heavy liner from Woodland direct. Is it flexible enough to go trough two 45 degree bends in a middle of 25 feet 13 by 13 chimney? I'm somewhat concerned.

TabeaK · Oct 11, 2022

Digging this out from years ago to say how awesome the temp logging setup is. As a data obsessed newbie wood stove owner who is also somewhat keen on home automation/monitoring, I am trying to figure out a good system for stovetop temp monitoring and alarms for too high temps. Wi-Fi and phone notifications are a must. Shocked to see there is very little in the market for off the shelf solutions.

Have some enquiries out with Aduro and Thermosure, but if I need to DIY, I am curious about the stovetop probe setup. Essentially I see a flat temp probe held down by a piece of metal and two magnets? What is that light rope-y looking stuff in the middle?

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Chimney top rebuild, Liner/Insert install, Data logging

HomeinPA

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