Air temp oil furnace wit restricted chamber

zepfan

We have a new customer that has an Air Temp furnace that is 6 years old, with a Beckett NX burner. Since it was installed it had not been serviced or cleaned, until today. The furnace is blowing black smoke everywhere, and has a positive pressure over fire, and negative pressure in the flue pipe. This is with the head setting at .5, almost closed. I am assuming that due to lack of maintenance that the furnace is restricted. My concern is that with just the two small cleanouts at the bottom of the exchanger, and removing the flue pipe may not be enough to get the heat exchanger clean. I am afraid that heat exchanger replacement may be the better option. Does anyone know the best way to go about cleaning one of these barrel type heat exchangers? Even with a sootmaster I don't know if it will get completely around it. Also with the nx burner I am finding it hard to make air adjustments with the the unit running. If you leave the spline nut loose where the head will move, oil leaks out. Is the intent to make the adjustments with the spline nut off, then shut off the burner and put the nut on? Or can the spline nut just be left off?
Thanks to all

STEVEusaPA

What's the model number of the furnace?
I've complained about the spline nut issue to Beckett (and anyone who would listen) since it first came out. Usually if you left the spline nut loose, and tightened the nozzle line, you damaged the nozzle line flare.

Your 2 issues are cleaning and set up.
Set up:
You must follow the instructions to zero out the head first, then set the head to what is recommended for that furnace. Lock it in and it's probably fine.
To fine tune I leave the spline nut off and attach the nozzle assembly snug with an e-clip.

Cleaning:
The chamber is probably fine. You can pull the burner and, depending on the model, the entire chamber, carefully, to clean it. You might be able to just pull the burner, and take a look inside.

Without knowing the model number, you may need to fire that with a positive over fire draft.

EdTheHeaterMan

I have cleaned many of these heat exchangers in my oil burner career. It is easily done with the correct tools. You need a 1-1/4" diameter brush with a long handle and you need a flexible metal hose for your soot master. here is the hose attachment available from RE Michel and other mastercraft vacuum distributors. The brush is also available from RE Michel. The REM part # 5E055 and 7M070

Here is the way I used to do it.Place the flex hose in the cleanout opening and the brush in the breach. With an in and out movement of the brush and the vacuum hose you will get most of the soot out.

STEVEusaPA

Got to lighten the load. On my soot master I use pool pump hose. Using the proper diameter, the original soot master hose ends fit it just fine. And I get to make my own length. For the flexible hose, a piece of garden hose, ends cut off, works fine.

zepfan

Thanks to all that responded. I appreciate it very much. The model and serial number of the furnace are air temp model# RHF-ANE serial# DN248244. Made in 2016. I assume that zeroing out the head is loosing the acorn nut sliding the head all the way forward, then using the 5/16" screw (1-5 setting) to set the proper co 2 and smoke numbers. All the information I could find on the furnace indicated it needs a .01-.02 overfire draft and .04-.05 in the stack. Thanks again.