Fahrenheit Endurnace 50F Project

That definitely sounds like lack of air in the firebox.

Yes, if the room blower fan is 'stealing' air from the intake (combustion) air inlet, you will be fighting to tune the stove -every time it runs-.
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You don't -have- to run your OAK to outside air for testing, just use a 4 - 5 meter length of pipe and route it to a location that has stable air / will not be affected by any furnace appliance in the basement, and drawing clean (not dusty) air.

* I would also be snaking and blowing out the air intake from the firebox -> back to the stove inlet with compressed air, to make sure there is not foreign material in the stove's air inlet pipe .. Re-verify the intake air path to the firebox is clear.

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re: test equipment, 'fighting' with measuring equipment not really designed for the task (meat thermometer / wood stove thermometer) just leads to guessing and frustration, speaking from experience here when I was starting out. Consider purchasing some more accurate (digital) temperature measuring equipment for the stove.

 

I think I'm going to have to buy a bunch of equipment for testing. It's a must have. In an install like this I'm into too much guess work and it's kicking my butt. You are very correct in that it would take the guess work out of the chimney being the issue.

 

The fire box and build up on the window is pitch black soot. I've getting an extremely dirty burn, even with the air intake wide open.

 

I'll double check the air intake. But it should be clear, as I had it ripped off the stove during tear down.

I know the thermometer isn't great, but it's what I had at the time. What did you buy for your testing?

Also, I'm open to opinions on what people bought for magnehelic gauges. I'm not going to be able to borrow one from work.

I'll find a chunk of pipe and get the intake away from the distribution blower air intake.

 

Hi ban83,

Here's what I've been using:


To measure firebox temp off glass: ( One here is an "OEM" branded IR gun )
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Etekcity Lasergrip 774 Non-contact Digital Laser IR Infrared Thermometer Temperature Gun, Yellow/Black
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http://www.amazon.com/s/ref=nb_sb_s...rmometer&sprefix=digital+therm,industrial,219


Started out using this type, offset from the stove exchanger 18" to prevent hitting "MAX" display:
( Been using one of these for years to measure A/C vent output w/ remote probe in vehicles here )
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http://www.amazon.com/Digital-LCD-D...?srs=9617672011&ie=UTF8&qid=1449853852&sr=8-3



To measure heat exchanger output from stove: ( Same model used & recommended by slvrblkk, dopps, and IHP here, THANKS guys. )
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Signstek 3 1/2 6802 II Dual Channel Digital Thermometer with 2 K-Type Thermocouple Sensor Probe for BGA rework HVAC 1300
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http://www.amazon.com/gp/product/B00FFYEPVQ?psc=1&redirect=true&ref_=oh_aui_detailpage_o03_s00

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Using a light source in a darkened room is an excellent way to -visually- verify passages,

I use a small barrel LED flashlight, an scoping automotive inspection mirror (on a stick),and a "compact mirror" raided from the ladies makeup drawer..

Using compressed air:

* Disconnect any air pumps, vacuum switch, etc. lines at the device and plug before using compressed air to prevent damage, unplug and blow air through -> back towards the port after cleaning, to ensure the line and opening are clear *

Use as much air as possible without stripping any paint off the stove: Common Sense applies here ..

Use a rag wrapped around a blow gun attachment to get a good seal @ the burn pot opening and blow back towards the Inlet,
place a clean empty pellet bag loosely around the port opening to act as a bag and check after inital cleaning, if you
find any material, keep going and use plastic or wood cleaning rods / tools and air to continue cleaning ..

Then visually inspect / repeat / until you are confident the passage is clear ..


Same procedure for the Heat Exchange -> Combustion Blower housing passage(s) ..


Write a list, check off each item, move on to the next item. Narrow down the possible issue causes.


Heat Exchange Tubes:
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Using some 220 Grit sandpaper and a piece of printer paper, sand a small section of a Heat Exchanger tube and collect the
debris on the paper - if Black in color, your Exchanger tubes may be carbon-insulated, need to get that carbon off the
Exchanger Tubes, it's robbing heat exchange output.

Use the finest grit sandpaper that will remove the carbon, and take your time, however tempting to use a coarser grade to speed up the process.

-Hand sanding only, no power tools.-


Combustion Blower:
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Once passages are verified clear to your satisfaction, closely inspect the Impeller, clean up to 'new' condition,
and inspect the plate where the impeller collar meets the motor shaft, remove any buildup using a brass brush / tools
and 220 grit sandpaper as needed - make sure the motor / impeller are not dragging on any buildup. -

* If the passages are clean, and the impeller / motor is clean, and still getting poor air, then consider
a tired / EOL combustion motor as a possible poor air cause, given the initial condition the stove was in, as received. *


Tuning:
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set the fuel type to proper fuel, reset any draft or fuel trims back to zero / default, and start tuning
on setting (3). using the damper screw to dial in your air setting, 1/4 turn at a time, waiting 10-15 minutes
EACH TIME turned, to allow air & temperature readings to stabilize. Don't rush it.

Do not change settings, get one setting 'tuned' first.

Lively flame in firebox, stable temp. reading on output, dial-down damper screw until flame starts to become 'lazy',
temp starts dropping, then dial damper screw back up (increase air) until flame is lively again, temp reading increases.

Once your air dampner is dialed-in, that's the stove's 'sweet spot' for air.

Always tune for a little -more- air first, then you can back down air / fuel using the stove's trim settings in the control panel as needed.

** Follow any recommended tuning procedures from your manual and fellow Fahrenheit owners here. **

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This is what I do / have done here. Much different stove. No damper / screw, I have to adjust air using the combustion blower RPM settings in the stove's control panel here.


*** You have a lot of great help here - this is not meant to take you off-course from more experienced help, just some tips that helped me rehab the stove here.

 

This is excellent. I always appreciate different views. Over the last 24 hours I have got a pile of information and ideas from people. I decided not to work tomorrow so I'm going to call a buddy of mine to come give me a hand and see what we can shake loose.

I'll borrow my Raytek IR gun from work tonight and double check if we have an anemometer kicking around. I don't think we do but found one at staples I like and will try to purchase at a local store, but I think it'll be online order only. The anemometer I want to buy also does temperature readings and will accept a type K thermocouple and has a max temp reading of a little over 2000F.

 

You got a handful of remedies from different angles from different folks. Some bright ideas should bring closure to this stubborn situation you/furnace are in.

 

I checked mine today, the furnace pulls the outside air in pretty strong where I feel the air rushing in if input my hand on the vent I used, then it turns VERY cold....I would assume it's a large volume of air moving fast.

 

BAN83, do you have an update?

 

Nice. Matt provided me with some specs for air flow readings. They are as follows.

With a freshly cleaned exhaust system,
Cold: 2100-2200FPM (Feet Per Minute)
Hot: 1800-2000FPM (any more than a 300FPM drop from cold to hot would indicate a weak exhaust blower.

So I am going to get an anemometer ordered and will check the air readings.

 

Sail switch was working ok.

Thanks for the reminder that the older units always burned dirty. As for upgrades, I think I have all the upgrades done to mine that you have done to yours, except a V4 burn pot. My upgrades/mods are as follows.

Larger impeller
Larger blower motor
Upgraded OEM sail switch
Upgraded OEM exhaust manifold
Closed in a portion of burn pot holes to force more air into the bottom of the burn pot.

Please let me know if I am missing anything that I should be doing to this stove to help with burn quality.

 

I do, I started typing an update earlier but got side tracked.

So yesterday I had a buddy of mine come by to give me a hand. He's a smart guy and I figured the two of us might be able to come up with some things, as I have been keeping him up to date on my stove since I got it. He's actually the guy that went with me to get it and helped carry it down stairs. We also went through the ideas that all of you have provided.

The first thing I did yesterday morning was redo my stove door gasket. I had always been suspicious of the job I did the first time.

When my buddy got there we removed the burn pot and looked it over for anything that may be causing air flow issues. Before reinstalling it we cleaned the back passage area again. This yielded about 3 cups of crap from the back passage area which I had already gone over twice. Wow! all I can guess is I either didn't do as good of a job cleaning it as I thought I did, or my test fires loosened the crap up.

We then reinstalled the burn pot, checked it for fit and blew a pile of air through the intake to try and dislodge anything that may be stuck. We then checked the air path buy putting a bunch of smoke into the air intake. The air path seems to be ok, but a good portion of the smoke seems to want to go down the front of the burn pot, rather than up past the heat exchangers and down the back passage. I've always wondered if the two exhaust ports in the bottoms of the stove are too big and should be smaller to force more exhaust to go up through the heat exchanger. Thoughts?

The last thing we did is turn the unit on with just the blower running and removed the cleanout on the base tee at the back of the stove to check for a change in air flow rate at the intake. Neither myself or my buddy felt any change in the flow rate through the stove. I will triple cheek this with the anemometer when I get it.

Once we were done all the above items we fired the unit, and amazingly enough, it is actually burning a lot cleaner. There is still a bit of soot build up on the glass but nothing like before. The flame is visibly more aggressive and I can see changes as I tweak the air intake damper.

On the heat output front, it's still not very hot, at least in my eyes. On heat setting 5 I still only get 120 - 130 f temps from the distribution air right at the output of the deflector. That being said, my main goal yesterday was to get it burning cleaner first. I am still going to go over the heat exchanger tubes as CleanFire has suggested, as well and get a better thermometer to check my temps.

As far as stove temp readings in various areas, I have the following readings for you guys to ponder. The readings were taken at heat setting 5 after the stove had fully heat soaked and were taken with a IR gun and always from a flat back portion of the stove.

Stove Fire Box top left side of door - 280 C
Stove Fire Box top left side of door - 190 C
Stove Fire Box middle bottom of door - 160 C
Air output from distribution blower was about 125 F, temp was taken with the meat thermometer shown in an above post.
Exhaust Temp - forgot to do but will be conducting tests again.

The following readings were taken at heat setting 3

Stove Fire Box top left side of door - 180 C
Stove Fire Box top left side of door - 160 C
Stove Fire Box middle bottom of door - 130 C
Air output from distribution blower was maybe 100 F, temp was taken with the meat thermometer and it doesn't read that low.
Exhaust Temp, just before entering pellet vent was 80 C. Measured with IR gun.

I am going to clean the back passage again, to make sure nothing else came loose and then repeat the tests.

 

Here is a pic of the stove burning on level 5. I have a video my buddy took as well which shows the flame better. Will need to post on youtube I guess though so you guys can see it, but I've never used youtube.

 

We're getting somewhere
I was about to post on my start up of the Harman to post update on chimney test.

 

Given you are pulling in basement air, which may be up to 20 F + / 8 - 10 C colder vs. inside room air, Temp. at the heat exchanger outlet is actually pretty good, given what Dex & all have posted here. ( Learning a lot in this thread, your furnaces move a lot more air vs. the small stove here - our FHA oil furnace puts out about 140 F / 60 C at the first vent, closest to the heat exchanger, if that helps. )

Glad to read you're making progress. Keep cleaning.

 

Yup, Making progress. I left it burning all night last night on #3 heat setting. House was about 21 this morning upstairs and basement was 25ish. I would have thought I'd get a bit more heat on #3, but hey, I still need to keep at it. I need to get it putting out more heat if it's going to be useful to me in the dirty cold weather.

Oh yeah? How'd you make out with your Harman?

 

Hey CleanFire, good to hear you are learning lots! I know I am!

Yeah, you make a good point, the air off the basement floor that the furnace was heating was very cold, I think it was are 17 C when I checked the air at

the intake to the distribution blower.

The bit of info about your oil burner does help. How far is the first register from your oil furnace?

I'm glad I'm making progress as well, thanks to a lot of input from everyone here on the forum!

Yeah, going to do some more cleaning tomorrow. Couldn't get to it today. I'll check back in once I have more updates.

 

Seems to be burning better with the door leak fixed. I didn't see any difference with the outside clean out cap removed. Verdict is still out there.