Need Oil Advice

B. Tice

Yes, the Guys are right on here. Got to pull the Millers down to clean them, and make sure the "rear chute " is clear.(by the way, the same procedure applies for Rheem and Ducane oil furnaces also.They have a rear slot). Check air supply chute. Most important, check roofjack cap.Every time. On gas CMF's check endcone (weldment) and heat exchanger under F&L switch , 80% of CMF gas units are cracked there.(the oil ones don't crack as much).

Bob C.

Need Oil Advice

One of my customers has a Miller MOD80 attached to
it is a Wayne m-ls burner. I was asked to clean it and change the
nozzel. I had no info on the burner and FW Webb denied it was ever made.
I got on the net and Wayne sent me the specs (nozzel size, electrode
settings,ect.) for this particular burner. The nozzel that belongs in it
is a delevan .60 80 degree B. The burner ran before I touched it and it
had the wrong nozzel in it! It had a hollow spray pattern it a .60 80
degree A. When I went to get stock I made sure to get both nozzels(just in case). So I replaced the nozzel with the same one that was in it. It
fired off but there was not complete combustion, oil would drip out of
the gun while it ran. I also replaced the electrodes, they were just nubs and there was a 1/2 gap between them. Then I put the nozzel
that Wayne suggested to be in there and it ran a litttle better. No matter what I do the stack temp is 600 degree F. When I first tested it the stack temp was 700 degrees, so I took apart the flue. It had one of those magic heaters in it, I threw that away and replaced with new flue pipe. this heater is in a trailer so there is only 3' of pipe in total. Anyways after performing a combustion eff test I got 11-12% CO. with zero smoke and stack temp of 600 degrees. Three weeks later the nozzel is clogged, soot build up all around it. I get a bad feeling about this unit-- the stack temp bothers me and why did it have a different nozzel in it ? did the last burner man know a trick? The nose cone is castiorn and is in good shape. I can't
figure out why it runs so bad after I leave. The over draft is -.1,.2 0ver
fire and -.4 in the breach. The pump pressure is set to 100psi and I did a cut off test to see if the soot was created from afterburn but it held just fine.I'd appriciate any suggestions

Alan R. Mercurio

Bob, it looks like you're really covering things well. Some of the things I would add to list of things you may want to check would be Vacuum you may have a possible restriction in your fuel line and also check the ignition transformer.And when you checked the draft over the fire did you check it with the blower running? You may have a cracked heat exchanger and in a system that old it would not suprise me.

Best of luck to you.

Your friend in the industry,

Alan R. Mercurio

www.oiltechtalk.com

B. Tice

Miller

A very common problem with this burner is a leaking oiltube.(firing assembly).I always have one on my truck.It is a Miller part#. Gun assembly for Wayne M. This oil blows into the chamber creating problems.Also- it also sounds like a cracked pouch plate, too.I use .55 90 nozzles on ALL Waynes with cast iron cones.

Bob C.

B.Tice,Thanks for the response. I was wondering if the draw assembly (oil tube) could be leaking. I'm not sure what a pouch plate is I've never heard of one. Can you fill Me in? The nozzels that you use are the solid or hollow spray pattern?

Alan, thanks for the suggestions also, I,ll check the draft with out the blower moter running. I did check the vacuum it was 0.

Frank_17

mod

55x 90 A nozzle works well. These burners are tempermental. the pouch plate is the front plate where the burne goes through. the z dimmension is important too. if not just right ,you'll get a coke ring around the end cone.try slidding the nozzle assembly ahead a bit

Steve Ebels

Those old Millers

Are known for plugginh up in the heat exchanger. If it's the design I'm thinking of the HX consists of a number of vertical tubes around the back of the firebox. Soot and ash from poorley adjusted burners will accumulate around the base of the combustion chamber and around these tubes. Causes a drop in efficiency (high stack temp) and also heat to be retained in the combustion chamber. This causes the nozzle and the burner cone to "coke up". I have typically found that furnaces with this problem will go through nozzles like crazy. You have to pull the burner, the front of the furnace and the combustion chamber to see it. I'm betting that's what your problem is.

Dale

S E comment is a good one

The CMH Millers will trick you into thinking the flu products exit from the top when it's really from the back bottom. Pull the fire chamber out and take a look. Also, with trailers I'm always suspicious about combustion air really being there and not clogged or blocked, also return air does the closet door pull shut from not enough return when the blower comes on? Leaking supply ducts under the trailer can make the trailer negative enough to starve air supply. Good luck, tough call and you don't give up !

Bob C.

Thanks Guys

I want to thank all the responders, you all shed some light on my situation and reconfirmed some of my suspicions. It seems that sometimes I don't want to go that extra step if I'm not totally sure or have good reason to. I guess if you bark up the wrong tree to many times you learn to be weary of barking and just look up the tree first.

THanks a Bunch.

Bob Cat