Nozzle after drip

Firedragon_4

would check;
1. Tube pitch, should be 5-10 degrees towards nozzle. Even a welded tube can be pitched using washers.
2. Openings at end of tube should be clear.
3. Leaks on and about pump. High pressure leaks should be found using a piece of newspaper between lines and fan opening.
4. Pump seal leaks. Do fuel cut-off and pump(only) vacuum tests to check seal and cut-off.
5. Ambient temperature. Place thermometer in housing on shut-down and wait three minutes. If it goes over 120F, draft problem and post purge may fix it.

It may not be a nozzle after-drip and these will find it in any case.

Ken D.

Nozzle After drip

Any one have any insights on oil burner nozzle after drip? We run into one every so often. The nozzle strainer check valves do work some times, but not always. The oil will sometimes run back and eventually end up on the floor. Sometimes increasing the pitch of the boiler is not practical on a large boiler. Any advice will be appreciated. Thank you.

Weezbo

older burners have that problem and all kinds of\"studies\"

about just what positive cut off was and there was stuff about too much residual heat causing expansion of the oil in the gun and somewhere along the line i noticed there was a little hole down stream of the gun after a while they seemed to abandon that stradgey...then about that time there were these cheezy oops plastic nails that were supposed to do the trick...the idea behind them was that it would allow flow and then Lock the oil ahead of the nozzle like a check valve sorta...er...it is difficult to tell if it works or just slows down the drip to a dull roar it definitely is Not a nozzle problem..The post purge is a good thing as it gets the flue gasses out and away and cools the temps down after the boiler shuts down which in theory cools the gun and reduces the oil expansion out the nozzle... the newer burners i havent seen that problem with in a long time...then again i dont do a heck of a lot of service work anymore...see if you can reduce the heat with a post purge....

Rookie_3

Ken

Most common causes of after drip are having a bad PRV causing poor cut off, you should replace the pump if your getting more than a 20% drop when you do your cut off test.
Overheating from the nozzle being too far into the chamber is another possibility and air in the nozzle gun would also cause after drip but that is usually self correcting. Just a few things I would look at first, good luck.....ROOKIE