Seeley GDH Series, Installation, Startup, Operation, Service & Maintenance Manual

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Technical Information
GDH Series Direct Fired Ducted Heater Page 11 of 16
GDH Selection Table
The prefix ‘GDH’ indicates gas duct heater. Number following indicate Model capacity in megajoules per
hour (MJ/h). Heating air flow is rated at 14 m/s velocity over the burner with a pressure drop through the
heater of 125 Pa.
Application examples for GDH heaters and AL Series coolers:
Table 1 - Models with Dampers
For installations requiring reduced air flow on heating, cooler runs on high speed for heating and cooling.
Lower air flow for heating is effected by dampers closing to about one third of high speed air flow.
GDH
Model
Nominal
Cooler Match
Cooling Air l/s Heating Air l/s kW @
1.75 kPa
kW @
1.12 lPa
Min Max Min Max
1500 AL36 15,000 21,000 7,000 11,000 440 293
1100 AL30 10,000 14,500 4,500 7,000 259 172
340 AL25 6,500 9,500 2,200 4,500 132 94
265 AL22 4,000 6,400 1,400 2,200 1+10 75
210 AL18 2,800 4,500 900 1,400 87 58
Table 2 - Models without Dampers
For installations requiring the same air flow for heating and cooling
GDH
Model
Nominal
Cooler Match
Air Quantity L/s
kW @
1.75 kPa
kW @
1.12 kPa
Min Max
2500 AL33/36 20,000 15,000 732 -
2110 AL30 14,500 9,000 586 390
1585 AL25 8,800 6,000 440 293
1055 AL22 5,800 4,400 293 176
790 AL18 4,200 2,400 220 148
525 AL15 2,200 1,500 117 100