Greenheck DG/DGX Pilot Ignition (470651_IOM) - Manual (Page 17)

6. Set the Maximum Firing Rate
Monitor the unit’s actual temperature rise by placing
a thermocouple in the unit’s inlet and a second in the
discharge, three duct diameters downstream of the
burner.
Send the unit to maximum fire by disconnecting and
isolating the wire connected to Terminal 3 on the
Maxitrol 14 or 44. See images on next page.
While monitoring the unit’s temperature rise, set the
maximum firing rate by adjusting the regulator until
the designed temperature rise is achieved. After
setting the maximum firing rate, reconnect the wire to
the amplifier.
NOTE
The low fire time delay must be set high enough to
provide at least 10 seconds of low fire while the unit
tries to light.
“ W.C.
“ W.C.
“ W.C.
F
PSI
“ W.C.
“ W.C.
MAX BTU/HR
BTU/H MAX
NORMAL MANIFOLD
PRESSURE
PRESSION D’ADMISSION
NORMALE
MIN GAS
PRESSURE
PRESSION DE GAZ
MIN BURNER
PRESSURE DROP
PERTE MIN DE PRESSION
DANS LE BRULEUR
TYPE OF GAS
NATURE DU GAZ
MIN BTU/HR
BTU/H MIN
MIN GAS PRESSURE
FOR MAX OUTPUT
PRESSION DE GAZ MIN
POUR PUISSANCE MAX
MAX BURNER
PRESSURE DROP
PERTE MAX DE PRESSION
DANS LE BRULEUR
MAX GAS
PRESSURE
PRESSION DE GAZ
MAX
DESIGN ∆T
∆T NORMALE
EQUIPPED FOR
CONCU POUR
SCFM “ W.C.
EXTERNAL STATIC PRESSURE
PRESSION STATIQUE EXTERIEURE
AGAINST
CONTE
NOTE
Do not set the burner maximum firing rate based on
gas pressure. It should be set based on the unit’s
designed temperature rise shown on the direct gas
label.
NOTE
Clockwise rotation increases the temperature
rise, counterclockwise rotation decreases the
temperature rise.
NOTE
The minimum setting for the maximum firing rate
may be higher than required. This is acceptable, the
burner will modulate as needed.
Direct Gas Nameplate
Regulators and Modulating Valves
Remove cap to access
maximum firing rate
adjustment
Remove one wire to
send the unit to the
minimum firing rate
Separate Regulator and Modulating Valves
Minimum firing
rate adjustment
Combined Modulating Regulator
Maximum firing
rate adjustment
Remove one wire to send the unit
to the minimum firing rate
Minimum firing
rate adjustment
7. Set the Minimum Firing Rate
Disconnect and isolate one of the wires running to
the modulating valve to send the unit to its minimum
firing rate. Set the minimum firing rate by adjusting the
needle valve.
After setting the minimum firing rate, shut off the
pilot to ensure that the flame safeguard can still read
the main flame signal. Reconnect the wire to the
modulation valve and open the pilot shut-off valve.
IMPORTANT
Setting the maximum firing rate during mild weather
conditions may cause the high limit to trip out during
extreme conditions requiring manual resetting.
NOTE
Gas trains are equipped with either separate
regulators and modulating valves or with a
combined modulating valve.
5. Set the Low Fire Time Delay
Set the low fire time delay to 75% of its maximum
setting. See corresponding image(s) for the location of
the time delay setting.
Model DG / DGX Pilot Ignition Make-Up Air 17
®