Pix of a furnace I want to convert

[doug]

For cheap do this.

Im glad you work metal

Looks simple enough. How do you regulate the heat with this set up?

[Chaz]

Thanx Doug. You took the question right off my fingertips. 
I can build js=ust about anything but I don't necessarily know how to make it work.    I love the creating part and look forward to doing it I just don't know how all this works together.

[Dead Eye]

Looks simple enough. How do you regulate the heat with this set up?~

 Ohh dang I forgot a few important details- Wile brazing them together add into the joint area a 1/4" coupler (used to join all thread, looks like a super fat 1/4" nut), this is were the thermocouple fits in. or if you get  enough fill in the joint (sil phos) drill and tap.

  I use this pid and k thermocouple

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=350267486390&ssPageName=STRK:MEWAX:IT

Add a relay and cartridge heater and you are set.


 

[Dead Eye]

 When making the short pipe " be sure the inside diameter is an exact 3/8" or 1/2" as you want a good fit for the cartridge heater.

[Chaz]

Seems reasonable. Is that what you did or are you just aware of doing it?

The latest issue I "THINK" I may have resolved is increasing the combustion chamber length to the "target". It was only about 9" and I read where you need 12". I just used fire brick and KAO wool (creamic wool) to make a square tunnel leading to the round hole the burner was in. Do you guys know of any reason this won't work? Here are some pix:





You can see the round firebrick fire box back inside the furnace. I hope the round burner in a square hole won't have any adverse effects.

Thanx for the help!
  Chaz

[doug]

Thanks Dead Eye. My mind lacks imagination. It's the same way my siphon is controlled.  A 1/4" coupler what a simple way to mount the thermocouple.

[doug]

Chaz,
 In my furnace the refractory was crumbling apart. I was under the impression that refractory was only used as a sound deadener. So I took the refractory out and didn't replace with anything. If I'm wrong in doing that somebody please tell me so I can make it right .

[Dead Eye]

Chaz,
 In my furnace the refractory was crumbling apart. I was under the impression that refractory was only used as a sound deadener. So I took the refractory out and didn't replace with anything. If I'm wrong in doing that somebody please tell me so I can make it right ~

 VERY BAD idea Chaz, Refractory is very high temp insulation that protects the steel from melting,warping,cracking,and general fatigue.
 I was on a recent call (Fire dept) were the oil boiler (not modifyed but about 15 year old) burned out the combustion chamber. The unit was sitting on a concrete pad that got so hot it started the floor under it smoldering.
 I ran big boilers at work (12 million btu vapor heaters) for 10 years, we took them apart every year and repaired the refractory.

It is even more important to have good refractory when the cycle rate is high (fire on,fire off) as the steel will expand and contract with each cycle leading it warpage and cracking, once a crack is there the superheated gas will blow through it and become a big hole very fast.

[Dead Eye]

 The proposed extension may work as you plan but I see a few pitfalls in it, first is the leak on the mount plate see attached pic.

 2nd is the mount plate will need to be extended , made into a liped box of sorts so the burner is not to far inside.

 3rd is if combustion is not complete (often a issue when tuning these set ups) the wool and brick will saturate will unburned oil leading to God only knows what.

 Safety First.

[doug]

Dead Eye,
It was me that removed the refractory from the burn pot. Now I have to find out how to replace it.
Anybody have any suggestion? Fire brick? I see there's several diffirent types of refactories.

[Dead Eye]

 The easy way is to order from Aireco or ReMichael or any HVAC supply the factory replacement. Have Model and serial numbers with you. Most residential units have that roundish hut looking deal in them. Firebrick works but I stopped using it years ago in preferance of plastic refractory

http://refwest.com/plastic.aspx

 The plastic is ment for bigger industrial boilers, it "works" like half dryed out play doe, you put a piece in place then use a air hammer or dead blow hammer (orange plastic hammer) to tamp it into place. I would be carefull with the tamping force as the residential units are thin steel.  If you need it overhead or vertical for a good distance up then you need to tack weld pins on the wall to hold the refractory in place till cured.

 To cure/harden the plastic run heat on it, take your sweat ole time do it slow, if you fire it to fast the escaping steem from within will make cracks in it  ( you will allways get a few hair line cracks no biggie). Start with an electric heater for a day then salamander heater

 

[Chaz]

Thanx Dead Eye.
In reference to your pitfalls (Which I GREATLY appreciate your insight!) I have new gasket material for the mount plate. The leak was with the old fuel oil set up before I got the furnace so a new gasket should be the ticket.

I'm not sure what you are saying with the second?  It's my thinking that the burner is going to actually be "back" further (out the front of the furnace) since I had to increase the distance from the nozzle to the "target". (sorry, I'm not seeing what you're saying) I am basically moving the round mounting plate that goes around the burner tube and mounts to the front wall of the furnace, up 3" towards the nozzle end of that tube. That will give me the 12" that I understand is necessary from the nozzle end to the target. But, I think this may also give undue leverage to the whole burner assembly on that plate, so I was going to make a stand/mount to go under the back, "heavy end" of the burner assembly to help support it. It will be sticking out past the front door of the furnace that covered all that up so I will have to make a "box" and attach (weld) it to the door to cover it up to make it less unsightly.

In regards to the third, do you think blowing the flame thru the "square tunnel" of fire brick then thru the round original hole in the burn chamber will effect the flame and burn? Oooohhhh I hope not.  This way worked out real well as far as creating it. I can fab up a stainless pan/tray or tunnel if necessary to keep any excess oil from saturating the "tunnel" brick or KAO wool.

I'm also wondering if I should maybe open up a small (or whatever size) opening in the top of the "tunnel" back at the mounting plate, to allow a circulation of air from the firebox back to the "beginning" of the tube and maybe help with bringing the flame forward. Just a thought since the nozzle is usually closer to the burn box.

Thank you guys for all the help and suggestions!!! And PLEASE give more if you have them!!! I think the next thing is to call ck burners and get my "stuff". 

Thanx again,
Chaz

[Dead Eye]

here are a few visulizations to help. The entire burner must come back at least 3 inch plus IF the tube you have is not 8"or 9" then that also.  See my post in plan section were I extended my tube to hold the ck block, you can see the weld.

[Chaz]

Thanx Deadeye. I think that is what I have done. Here is a rough sketch of what it was originally, then what I have done, and then what it would look like if you looked in where the burner goes. My concern is how the flame might react going from the burner, to about one and a half inches of a 4" square fire brick tunnel, then thru the original 4" round hole (where the burner use to go thru), then into the fire box.
If it all seems feasible, I'll continue on, otherwise, if someone knows it won't work or there will be problems, I'd like to save myself the trouble and then do something else.
As you can tell, this sort of thing bewilders me a little as I have no experience in it and really want to do it correctly - as best I can - the first time. I have built Hot Rods and major industrial machinery but when it comes to furnaces and fire, I'm a little tentative.    As has been said, "safety first". That is also why with this one, I will probably buy most all of the conversion stuff from ck. Then once I get a grasp of it, if I do another one, I may create more of the stuff myself.

[Dead Eye]

Looks like it should work out ok, These waste oil conversions are often trial and error with the combustion chamber design. #1 and 2 oils have a very low flash point compared to heavy oils. There is a lot a talk at altfuel group about the dreaded wet fire box, were unburned fuel soakes the chamber walls, the fix is what they call a liner or burn tube, this holds the fire and fuel together so it completes combustion. I am having a hard time explaining it~ Anyhow the small start of a square tunnel and the round hole could be beneficial in this respect, holding the heat in the spray of oil.

 Here is a diagram I am about to do. The 10" pipe is built and a tial run had wet walls inside, I will but a tube inside the help finish off combustion.