Direct Gas Make-Up Air
32
1. Energize the heating
Connect terminals R to W1.
2. Set pilot flame signal
Close main hand valve. Flame current must be
measured with pilot valve lit but no main gas flowing.
Set meter to μA DC scale.
Locate flame signal terminals
on the pilot ignition control,
place red lead on [+] terminal
and black lead on [-]
terminal. The signal must be
above 1 μA DC. Adjust pilot
gas pressure up or down,
if necessary, to achieve
acceptable flame signal. In
some cases, reducing pilot
gas pressure can increase
flame signal.
3. Set maximum fire rating
Open main hand valve and then set maximum firing
rate to the design temperature rise found on the direct
gas nameplate located on the outside of the unit on the
control center side.
Send unit to high fire by removing the wire connected
to terminal 3 of Maxitrol 14 or 44 Series amplifier. If
equipped with the Maxitrol SC Series amplifier, remove
the wires from terminals T1 and T2 and connect
terminals T1 and T2 with a field-supplied jumper wire.
While measuring temperature rise,
temperature rise =
discharge temperature - inlet temperature,
adjust
combo valve regulator to achieve desired temperature
rise.
Start-Up: Direct Gas-Fired Heating
24V Commercial Pilot System (6-inch burner)
4. Set the minimum firing rate
Set the minimum firing rate to achieve a small ribbon of
continuous blue flame across the burner.
Disconnect one of the wires going to the modulating
valve and isolate. Set the minimum firing rate by
adjusting the minimum firing rate adjustment on the
modulating valve. Cycle the heat to make sure the
burner can light at this low fire setting.
5. Resume normal operation
Reconnect wires to Maxitrol amplifier and modulating
valve removed in previous steps.
6. Perform final flame signal check
Set meter to μA DC scale. Locate flame signal terminals
on the pilot ignition control, place red lead on [+]
terminal and black lead on [-] terminal. The minimum
flame sense current is 1 μA DC. If flame signal is
insufficient, repeat steps #1-4.
Remove cap to access
maximum firing rate
adjustment
Remove one wire to send
the unit to the minimum
firing rate
Combination Valve Regulator and Modulating Valve
Minimum
firing rate
adjustment
Pilot gas pressure
adjustment
Pilot Ignition Control
