Greenheck TSU Base Unit Manual (464441) - Manual (Page 14)

Make-Up Air Unit 14
®
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. On Maxitrol SC 25 system, place
jumper between T1 and T2 on the amplifier.
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 ΔT
Δ
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.