Pleasant Hearth WS 2417 Outside Air Intake Build

[Das Jugghead]

At the end of 2018 I purchased a Pleasant Hearth WS-2417 woodstove. That installation and subsequent learning process is described here:

Pleasant Hearth WS-2417 install/challenges/questions/observations

A little background: I purchased a Pleasant Hearth WS-2417 about two weeks ago from Menards on sale. It is my first EPA stove and I am a moderately experienced wood stove operator. It is installed in my fireplace and connected to an insulated flexible stainless steel liner. I installed the...

www.hearth.com

Several issues have been on the list to address including rebuilding the outside air intake so that it was sealed from the living space and slowing down the incoming air. My current setup drafts very hard and as a result we burn through a burn cycle in a matter of hours. This was fixed by installing baffles but I could still feel cool air migrating toward the stove. I figured if I could seal the stove intake air off from the house I would be able to control the air and preheat it at the same time.

A few weeks ago I started designing and building the new intake for the stove. I installed it and ran several test runs even though the temperatures here were still warm - I did not want to find any surprises during the heating season. I will detail the build and testing results in this thread over the next week or so as I find time to post.

Pulling the stove and getting ready to take measurements for the intake box.

 

[Das Jugghead]

Rain today has driven me to inside chores and I am taking the opportunity to continue this thread.

My son and I pulled the stove out so that I could start taking measurements in order to design the intake box. One interesting discovery I found was that the primary intake box is of center on this stove.



Although being off center did not impact the design I was working on it was yet another item on the ongoing list of QC issues I have had with this stove. I am fully aware that this stove is a cheap $500 stove and not a high end quality stove but this is simple stuff that should not happen at all.

The basic plan was to create a sealed box on the bottom of the stove utilizing the stove legs for the corners. Inside the box would be gas pipe to bring outside air into the air box. The gas pipe would have holes drilled in the top of it and run parallel to the bottom of the stove firebox floor - the intention being that the incoming air would strike the hot bottom of the firebox floor and be preheated before entering the primary or secondary intake.

 

[Das Jugghead]

I bought a cheap sheet metal brake from Harbor Freight to bend the panels for the sides and bottom of the outside air intake box.

30 in. Mountable Bending Brake

Amazing deals on this 30In Bending Brake at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

The plan was to put a bend along the top of each panel creating a lip that would accommodate stove rope to seal the panels to the bottom of the stove.



Here are a couple of panels bent and test fitted:



I used stainless steel hardware to attach the panels to the stove legs. There is flat stove rope/tape between the panels and the insides of the stove legs. Between the tops of the panels and the bottom of the stove body (the floor of the firebox) I installed 3/4" stove rope. The gap between the top of the panels and the bottom of the stove is 3/8".

 

[Das Jugghead]

Next up was a bit of house keeping. When my son and I removed the stove from the fireplace I noticed that the block off plate had seen some serious wear and breakdown so I took a side diversion to fabricate a new block off plate out of steel. The cheap metal brake from Harbor Freight made this process other easier as well as more accurate and durable.

Here is the cement backer board that was installed before:



and here is a close up of the wear:

 

[Das Jugghead]

I purchased a larger piece of steel for the block off plate and using a cardboard template I scribed the dimensions onto the steel allowing extra material for creation of flaps along the perimeter of the template. The purpose of the flaps was to assist in keeping the block off plate in place as well as creating a lip to place rock wool along to help seal the gaps.

I used a six inch pipe to scribe the circumference of the opening for the flue pipe:



Bending the sides of the block off plate were pretty easy:



Bending the flap for the back wall was a bit more challenging. The length off the back wall bend was shorter than the flat clamping bar on the metal brake. This required me to cut the flat clamping bar with a hack saw to be able to fit it in between the two side flaps. The process of sawing through the flat clamping bar took me about forty-five minutes. I used a piece of 10 gauge steel clamped in place as a sawing guide.



Most of the way through:





Bending the final flap:



Still need to trim the angle along the side flap with shears:



View showing the front:

 

[Das Jugghead]

Now that the block off plate was done and installed it was time to get back to the interior design and layout of the outside air intake box.

Next up was fabricating a plate to attach to the bottom of the primary air intake for purposes of holding up the gas pipes and for forcing the incoming outside air to travel along the hot bottom of the fire box floor before entering the primary intake or the secondary intake.

Here is a test fit of the gas pipes along the bottom of the stove:



And here is the plate that I fabricated to hold the pipes in place and force the air along the bottom of the stove before entering the primary or secondary intake. The hole in the middle is for the primary air intake. The piece riveted along the bottom is both for strength to keep the plat from bending or sagging and to create another baffle for the incoming air to travel around before entering the primary intake:



The flaps riveted to the top of the plate are for holding the gas pipes in place. They also lend a little rigidity to the plate itself:

 

[Das Jugghead]

So the last post did not include how I made the plate that attaches to the bottom of the primary intake box so I will detail that here.

I used a piece of cardboard to create a template for the bottom plate in order to get the correct size. I was able to scribe guidelines showing the sides of the primary intake box which allowed me to determine where to drill the holes for the mounting bolts. My plan was to attach the bottom plate by drilling and tapping holes into the primary intake box. . Once I had the location of the primary intake box marked on the bottom plate I was able to mark and drill the mounting holes in the bottom plate. Next I shimmed the bottom plate into place and used it as a template to drill the locations of the holes in the primary intake box. Apparently I neglected to take pictures of this stage and the picture below shows the bottom plate with all of the mounting holes drilled and tapped as well as the cut out for the primary intake:



Tapping threads:




I ended up using a piece of paper to ascertain the location of the primary intake opening and the location of the opening for the primary intake.



I used stainless steal bolts and washers for the attachment:

 

[Das Jugghead]

With the bottom plate fabrication completed I moved on to the gas pipes which served as outside air inlets into the airbox under the stove. I used 3/4" gas pipe. The outside air comes in through the ash cleanout for the fireplace. Last year I installed a four inch flexible aluminum tube in the ash cleanout and my plan was to use a 1.5" flexible radiator hose to navigate the afore-mentioned aluminum tubing ultimately connecting to the gas pipe leading into the stove.

So here is the inlet manifold that feeds outside air into the air box under the stove:



I marked the pipes and drilled holes along the tops of the pipes. This way the outside air coming out of these tubes would strike the bottom of the stove's fire box and be heated before being drawn into the firebox via the primary intake or the secondary intake. Unfortunately I have managed to lose the pictures of the holes but they are graduated in size from the far end where the pipe caps are toward the end where they connect to the elbows - the larger holes at the end with the pipe caps and the smaller holes near the elbows.



I used a 1" hole saw to cut a hole in the rear panel of the air box under the stove to pass a 3/4" gas pipe through to the ash cleanout tunnel. I had anticipated having to use insulation to seal this hole but as it turned out the tolerances were quite close and I actually had to use a round file to open the hole enough to allow the gas pipe to pass through which made for a good seal in an of itself.



I installed a stainless steel pipe clamp on the inside section of the gas pipe where it passed through the back panel of the air box to keep it from moving out. In this picture you can see the stove rope that I used to seal the top of the air box plates to the bottom of the stove.



Here is the flexible radiator hose that I attached to the intake manifold:



Finally, here is the far end of the radiator hose as seen from outside:

 

[bholler]

Have you ever measured the draft and taken actions to get it within spec before doing all of this?

 

[Das Jugghead]

What I thought would be the final step of fabricating the new outside air intake/air box was the bottom panel of the air box. This proved to be a little more challenging than I had envisioned. The bottom panel is held on by two sets of four stainless steel bolts that are set in the bottom flanges of the side panels. I sealed the seams with flat stove tape/rope and the gaps with 3/4" stove rope:

 

[Das Jugghead]

So as alluded to in the previous post there was one final step to be done which was to slow down the secondaries. On a test burn they raged liked mad so I decided to modify the nuts I had installed in the secondary tubes. The solution involved grinding down the threads of those nuts and pressing smaller nuts inside the larger nuts.

 

[Das Jugghead]

Have you ever measured the draft and taken actions to get it within spec before doing all of this?

No sir I have not - I would not even know where to begin to measure the draft.

 

[Das Jugghead]

Since the plates for the air box were painted with stove paint, the stove was already out of the fireplace, I decided that we should fire the stove outside to cure the paint.

 

[bholler]

No sir I have not - I would not even know where to begin to measure the draft.

With a draft gauge or manometer.

 

[Das Jugghead]

With a draft gauge or manometer.

Okay a couple of questions in that regard:

1. Where does the manometer connect to measure draft?
2. Would I need to drill a hole in the flue to measure the draft?
3. What is the method of correcting overdraft?

 

[bholler]

Okay a couple of questions in that regard:

1. Where does the manometer connect to measure draft?
2. Would I need to drill a hole in the flue to measure the draft?
3. What is the method of correcting overdraft?

1 in the flue
2 yes
3 dampers flue restrictions etc

 

[Das Jugghead]

1 in the flue
2 yes
3 dampers flue restrictions etc

Under "dampers flue restrictions etc" would intake restrictions qualify as a method of correcting overdraft?

I never considered measuring my draft as the stove goes through a load of wood like a flame thrower in a gas well. Ever since taking steps to slow down the intake I have been able to create longer burns and create more useable heat.

Not to come across as questioning your experience or knowledge base (as I do very much appreciate your input and responses) but at this point is there anything to be gained by measuring the draft?

One (for now) last question - what kind of draft numbers would be within the range of appropriate numbers?

 

[bholler]

Under "dampers flue restrictions etc" would intake restrictions qualify as a method of correcting overdraft?

I never considered measuring my draft as the stove goes through a load of wood like a flame thrower in a gas well. Ever since taking steps to slow down the intake I have been able to create longer burns and create more useable heat.

Not to come across as questioning your experience or knowledge base (as I do very much appreciate your input and responses) but at this point is there anything to be gained by measuring the draft?

One (for now) last question - what kind of draft numbers would be within the range of appropriate numbers?

No intake restrictions don't change the draft. It can control the stove but I find limiting the actual vacuum to be a better solution.

You would have to check with the manufacturer but usually -.06

 

[Das Jugghead]

No intake restrictions don't change the draft. It can control the stove but I find limiting the actual vacuum to be a better solution.

You would have to check with the manufacturer but usually -.06

Thank you sir.

 

[Das Jugghead]

When I reinstalled the stove and ran a couple of test runs I was surprised that it struggled to get and stay above 450 degrees. I traced the problem to my failure to reinstall the collar cover for where the flue thimble enters the top of the stove. I could actually hear air being sucked in there. Using some extra rock wool I filled the groove along the thimble and covered it with a collar secured with stainless steel band clamps. While there is rock wool sticking over the top of the collar the real meat and potatoes of this is hidden inside the collar where the gap or groove between the top of the stove and where the flue thimble enters the stove. I thought I had a picture of this but apparently was in a hurry to get this addressed and did not take a picture.

 

[Das Jugghead]

Just a short update on how the stove is performing since redesigning the intake to slow down the draft:

Loaded the stove last night at 22:30 approximately 80% full with ash​

Outside overnight temperatures hovered around 25 degrees​

Temperature in the house is at 73 degrees at 6:30​

Still a good sized "log" of coals along the back wall of the stove which I sifted and raked forward to front of the stove​

STT at 282 degrees.​

Will probably reload in an hour or so depending on when the house temperature hits 70 degrees.

Also finally got around to finishing the metal sheeting that covers the rockwool insulation around the fireplace. The last picture shows the metal covering and the load of wood scraps on the hearth that will be loaded in about an hour.