Service manual

A DJM3.2 MANUAL
Pot 1 (located next to terminal G)
is the curve matching pot. It is
possible to use the DJM3.2 with
several different Maxitrol valves.
Each of these valves has a
slightly different opening curve.
The curve matching pot allows
the DJM3.2 to be adjusted to
control all of these valves.
Pot Low Fire (located next to
terminal 1) is the low fire RPM
adjustment pot. This pot is used
to adjust the low fire RPM (low
fire air). The low fire speed is
adjustable from 1150 to 1400
RPM (high turndown) and 1800 to
2000 (standard burner).
NOTE: The light off RPM is fixed and is non-adjustable. Adjusting the low fire speed will
have no effect on the light off speed.
Combustion Set Up
Preview of Combustion Set Up
There are two burners available.
The high turndown (rectangular) burner
Top Board
Bottom
Board
2 amp fuse
Jumper R100
To be cut for
high turndown
burner
• Is capable of 15 to 1 turndown.
• You must cut the R100 jumper on the back of the DJM3.2.
• Pilot ignition at about 2300 RPM.
• 10:1 Modulation 1250 and 3400 RPM (20.8-56.6 Hz).
• 15:1 Modulation 1195 and 3400 RPM (19.91-56.6 Hz).
• Note carefully which “M” series valve is in use.
The Standard (or Round) Burner
•
•
•
•
Limited to about 2.5 to 1 turndown.
No jumper to be cut on DJM3.2.
Pilot ignition at about 2700 RPM.
Modulation between 1850 and 3400 RPM.
For Either Burner
• When measuring combustion, ensure probe of analyser inseerts fully into the flue connection to
the heat exchanger. Measuring at the flue outlet may be a diluted reading due to air mixing into
the flue.
• First set up high fire
• Then set up low fire
• Adjust midrange firing (curve matching pot)
• Adjust pilot
Page 29 Revised: 3/11/99