A
DJM3
IOM-17
20 of 27 Mar 99 R3
Pilot Set Up (Standard Burners)
Do not
set up pilot until you are confident the burner is operating with correct air/fuel mixture.
Ensure the pilot tube is free of debris and blockages. On standard round burners, set pilot as
per the following procedure.
1.
Install a 10,000‐ohm resistor in series with the flame
rod circuit.
2.
Connect a DC voltmeter across the resistor.
3.
The reading will be in millivolts if your meter does
not auto scale.
4.
Connect a manometer to the pilot line.
5.
Run the burner on main flame for a few minutes to
have the burner plate warm.
6.
Leave the pilot on but turn the main gas off. You will
have to jumper the DJM3 terminals PV1 and PV2 to
do this and remove the wire from terminal VFB 120 or VFB 24 (depending on valve voltage).
7.
As low pilot gas pressure can damage the ceramics, reduce the pilot gas pressure to 2.5
inches and immediately return it to a higher pressure. This is to ensure the pilot gas regular
responds properly.
8.
Adjust the pilot valve regulator to a pressure in excess of 4.5 inches pressure.
9.
Slowly reduce the pilot gas pressure while watching both the pressure and the voltmeter.
The millivolt reading should be increasing. At the point where it begins to fall you should
stop reducing pressure and return to the high spot.
NOTE
:
The fall in pressure could only be as small as a couple of millivolts. This point should be
between 4.5 and 2.5 inches pilot pressure.
NOTE
:
Some smaller burners (DJ40 250,000 BTUH and smaller), may need to have a screw placed
through the pilot air tube to reduce the amount of air to the pilot.
10.
This reading is used to determine the adjustment that will usually give the best pilot lighting
and proving strength. However, care must be taken to not adjust the reading for pilot gas
pressure below 2.5 inches water column pressure or you will break the pilot ceramics.
11.
Next, visually observe the pilot flame. It should be visible at a minimum of 3 of the holes
around the pilot. If the pilot cannot be seen then it is likely burning too deep into the pilot
box. If this is occurring check that the gasket on the pilot assembly is forming a tight seal.
Also ensure that the burner is located in the center of the burner tube. If it is mounted too
low then too much air can flow over the top of the burner and affect the pilot.
NOTE:
After set up is complete make sure to turn off dipswitch 5.
Ignition
Control
10,000 ohms
MV meter
OK
Too large a gap. Raise
burner plate up to
centre
.
