Installation Information
GDH Series Direct Fired Ducted Heater
Page 8 of 16
3.
Pilot solenoid valve opens. Pilot lights.
4.
Main solenoid opens, low fire starts (non-pilot units)
5.
UV cell sights flame. Flame established.
6.
Set gas pressure to pilot 1.0 kPa.
3.2.10.
Ensure modulating gas valve is fully open.
3.2.11.
Fit manometer to main burner pressure test point. Zero manometer to compensate for
positive pressure of air in ductwork, usually around 50-75 Pa. Turn main burner test cock on.
Check and set gas pressure as per data plate.
3.2.12.
Check temperature rise across heater (for space heating maximum rise = 48°C) with a good
quality thermometer. Measure temperature leaving air registers, measure temperature
entering heater. TR = Air Off – Air On.
3.2.13.
For GDH heaters, by using thermometer select a good position for high limit thermostat bulb
and fix in position. Do no mount bulb beyond confines of the heater. Set high limit to cut
out at 80°C. Fix bulb in position with bracket supplied.
3.2.14.
With a suitable CO-CO
2
combustion analyzer, check the CO-CO
2
emission from the heater.
Burner must not produce more than 10 ppm CO and no more than 3000 ppm CO
2
while still
maintaining a
CO-CO
2
ratio no greater than .003%.
3.2.15.
Reduce the air supply rate down until air differential pressure reaches approximately 60-70
Pa. Adjust air pressure switch to cut out. Recheck CO-CO
2
to ensure readings are within
limits. Record readings on combustion data care inside electrical box.
3.2.16.
Check modulating valve and ensure valve reduces gas rate proportionally. Ensure auxiliary
switch in valve motor stops burner at minimum low fire should be stable and travel the full
length of the burner.
3.2.17.
Carry out safety checks with gas supply authority officer.
Hand installation over to customer, explain full operation and the need for regular maintenance. Some State
authorities will require an annual combustion check in addition to normal maintenance and service.
