Startup
30
OAU-SVX005C-EN
2. Use only hand force to operate the gas control lever to
the “ON” position. NEVER use tools. If lever does not
operate by hand, replace gas valve prior to staring the
unit. Forcing or attempting to repair the gas valve may
result in fire or explosion.
3. Do not attempt to operate unit, if there is indication that
any part or control has been under water. Any control
or component that has been under water must be
replaced prior to trying to start the unit.
Direct Gas-Fired Heating Start-Up
Procedure
The following procedure must be followed for the unit
heating section to function properly. The following
procedures are to be performed after all electrical and gas
connections to the unit have been completed and the
outdoor air damper and evaporator fan operation have
been verified and are operating satisfactorily.
Refer to Alarms and Troubleshooting chapter for
additional information.
Tools Required
•
Voltage Meter (
A)
•
Amp Meter
•
Gas Pressure Gauge
•
Tachometer
•
Temperature Probe
•
Anemometer
•
Service Mirror
•
Small Refrigeration Screwdriver
•
5/16-in. Nut Driver
•
1/2-in. Open End Wrench
1. Confirm Unit Airflow
Important:
Accurate airflow readings require clean
inlet filters. If required clean or replace
filters before proceeding.
All Horizon direct gas-fired heaters are factory-
adjusted to achieve design airflow pressure drop (
P)
of -0.625 in. wc across the burner profile opening at
ordered unit SCFM airflow. The burner baffles should
not be adjusted. Outdoor Air conditions will cause the
measured
P to vary. Refer to
to see the
acceptable measured pressures that may be read at
various outdoor air conditions. Measure and record
burner pressure drop.
Note:
If burner pressure drop is not within the range
shown in
, refer to Airflow Troubleshooting
section of Alarms and Troubleshooting chapter.
2. Check Inlet Gas Pressure and Confirm Gas Flow
to Unit
Confirm gas flow and gas supply pressure to heater.
The Manual Shut-Off valve (MSO1) can be used to
bleed the supply line as needed.
Table 6.
Acceptable measured pressures
OAT (°F)
Burner Pressure Drop (in. wc)
0
0.720
5
0.712
10
0.705
15
0.697
20
0.690
25
0.683
30
0.676
35
0.669
40
0.663
45
0.656
50
0.650
55
0.643
60
0.637
65
0.631
70
0.625
(a)
(a) 0.625-in. design pressure drop at standard air condi-
tions.
75
0.619
80
0.613
85
0.608
90
0.602
95
0.597
100
0.592
WARNING
Hazard of Explosion!
Failed gas components could explode or leak
flammable gas which could cause a fire resulting in
death or serious injury or property damage. Do NOT
expose gas controls to pressures above 1/2 psi
(3.5 kPa). Refer to General Safety Information.
AVERTISSEMENT
Risque d’explosion!
Des composants au gaz défectueux peuvent exploser
ou entraîner des fuites de gaz inflammable pouvant
provoquer un incendie résultant en des blessures
graves, voire mortelles, ou des dommages matériels.
N’exposez PAS les régulations de gaz à des pressions
supérieures à 1/2 psi (3,5 kPa). Reportez-vous à General
Safety Information.