I kept a spare Beckett af-II burner for my Miller m/h furnace so I could get up running quicker. Then I can t/s and repair later. My installed burner motor bearing was getting obnoxious so I figure I'll just use the spare. Anyway, the spare has a cleancut pump. I am use to oil burner's click/hum/fwump burner lite in one fell swoop. We'll this pump I had to get use to the delay. Anyway it seems that with the pump spooled/pressurized that alot of times I hear extra fuel in there burning/ for a second or two till is sounds like normal.Some times it just lites normally like I'm used to. I can understand the theory of the fuel being released and normalizing but I would rather put the old pump back than this run like this. The tech who serviced this had the air at zero and not a very good burn. I went up to four and backed off with slight smoke and a nice flame. Something just doesn't seem kosher here. Looking fwd to getting away from Nordyne/Miller/Intertherm and oil and going with propane two stage. So far I've found a Trane/AS 60k that has a mobile home kit. Thanks for any help. GBY

 

Are you sure there is actual combustion taking place? If it has kind of a sizzling sound, it is probably the spark from the ignition transformer. I've never seen an AF-II on a mobile home furnace. Worst of both worlds in my book.

You should have absolutely no smoke. In a m/h furnace you will crap up the heat exchanger very rapidly. Give it a touch more air & see if you can clean up that fire.

 

Opps. It's an AF-15. No buzzing. It just sounds like extra fuel being burned for a sec. or two then the normal rumbling that I'm used to hearing with a normal burn. Other times it just sound like a normal start. BTW, do these act any different if the screen is dirty as I never serviced the pump, as I just swapped the burner and just changed the nozzle.
Will do on the air. Heard many times to back off on the air a bit after a clear burn. I like a clean flame. Miller is a good furnace just tired of messing with oil and want better efficiency.

 

The only thing I can think of is the internal valve on the pump opening too soon. Your pump doesn't have an external solenoid does it? If it does & has a delay in it, I'm guessing the delay has gone bad. The delay, built into the cord, is cheap & easy to replace.
It certainly can't hurt to change the pump screen.

What nozzle are you firing & what's the model of the furnace?

 

The 4 second delay does work. It's just like it' pressurized and has a shot of fuel that is a bit more than the regular spray. I can hear the extra burn for a sec or two and then the normal burn noise
I'm used to. It's a Miller cmf 80 with a .60 nozzle 75 k ,for 60k out. It can be upgraded to 90k in so I'm sure it can handle the momentary extra fuel burn. It works good with the regular A2VA pump.
Thanks

 

Are you saying you have a Clean-Cut on the burner now but had a A2VA-7116 on it previously? Otherwise, I don't understand the 4 second delay.

 

Yes, as all the other AF-15s I worked with had the A2VA-7116 pump. The clean cut was installed by the tech who serviced the burner for the person I bought it from. He had the supply cord grommet pulled and sent the extra two wires along with the power cord and put some putty in the hole. There must be a timer in the clean cut pump solenoid or delay terminals in the control. He also had the air completely shut off. Make me wonder about his work.

 

The delay for the Clean Cut is built into the cord head where it plugs into the pump solenoid. Normally the Clean Cut cord is wired to orange & white off of the primary control.
What control is on the burner? Can you take a couple of pictures & post them either here or on a photo sharing site such as photobucket.com?