Seeley GDH Series User guide

GDH Series Direct Fired Ducted Heater
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Installation, Startup, Operation,
Service & Maintenance Manual
GDH Series
Direct Fired Gas Heating

Table of Contents
GDH Series Direct Fired Ducted Heater
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Contents
GENERAL INFORMATION .....................................................................................................................3
About DGH & LU Units ..................................................................................................................................... 3
Standard Unit Details ....................................................................................................................................... 3
Extra Cost Options Available ............................................................................................................................ 3
Construction..................................................................................................................................................... 4
Main Burner Assembly .................................................................................................................................. 4
Burner Control............................................................................................................................................... 4
Valve Train .................................................................................................................................................... 4
Safety controls............................................................................................................................................... 4
INSTALLATION INFORMATION ...............................................................................................................5
Basic Installation............................................................................................................................................... 5
Example Installation......................................................................................................................................... 6
START UP............................................................................................................Error! Bookmark not defined.
OPERATING INSTRUCTIONS ..................................................................................................................9
TECHNICAL INFORMATION .................................................................................................................10
TECHNICAL INFORMATION ......................................................................... ERROR!BOOKMARK NOT DEFINED.
Technical Specifications .............................................................................................................................. 10
Dimensions / Weight / Configuration........................................................................................ 10
Air Requirements....................................................................................................................... 10
Gas ............................................................................................................................................. 10
LU Models Drive Details ............................................................................................................ 10
GDH Selection Table.................................................................................................................................... 11
Table 1 - Models with Dampers ................................................................................................ 11
Table 2 - Models without Dampers........................................................................................... 11
MAINTENANCE...............................................................................................................................12
Fault Finding Chart ......................................................................................................................................... 12
Service ............................................................................................................................................................ 13
WARRANTY TERMS AND INFORMATION .....................................................................................14
•IMPORTANT NOTICE •
Please leave this manual with the owner of this heater.
Please keep this important manual in a safe place. It is the owner’s responsibility to ensure that regular
servicing of this appliance is carried out. Failure to maintain periodic service work as outlined will void all
guarantees beyond statutory and legal requirements.

General Information
GDH Series Direct Fired Ducted Heater
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GeneralI nfor mation
ABOUT DGH &LU UNITS
The AIRA heater is a direct gas fired unit, compact and easy to install. There is no heat exchanger, no stack
and no stack loss. Direct fired heating is highly efficient because most of the heat goes into the air stream.
The heater is a complete or add-on package in itself, requiring only fuel and power connections after
positioning onto an adequate air supply. Basic GDH construction is an open ended duct framed at both ends
for ease of fixing into ductwork. Inside the duct is the direct fired gas burner mounted centrally across the
profile area. Gas valves and burner controls are mounted along the outside front wall of the unit.
GDH and LU heaters are available for use on natural gas or LPG (Propone), indoor or outdoor mounting.
The heaters are ideal for:-
1. Providing tempered fresh air changes to conform to regulations.
2. Providing automatically controlled warmth at maximum efficiency.
3. Providing tempered make-up air to replace air exhausted from a building.
4. Satisfying a wide range of processing, heating and curing requirements.
STANDARD UNIT DETAILS
1. Indoor or outdoor model (Specify on order).
2. Modulating burner control.
3. Remote reset provision
4. Control switch. *
5. Room thermostat.*
6. Remote reset button and indicator light.*
* Supplied loose.
Models GDH 210, 265, 340, 1100 and 1500 are fitted with motorized dampers which can reduce high air
flow rates (common to evaporative coolers), not always necessary for heating applications.
Models GDH 525, 790, 1055, 1585, 2110 and 2500 are full air flow for heating when an evaporative
cooler is the air source. LU models are full air flow complete with fan
EXTRA COST OPTIONS AVAILABLE
1. Remote control panel incorporating time switch, control switch, thermostat, lockout light and reset
button.
2. Operation on gases other than natural.
3. Inlet gas pressures exceeding 7 kPa.
4. High gas pressure switch.
5. Low gas pressure switch.
6. Modulating burner control
7. Vertical discharge

General Information
GDH Series Direct Fired Ducted Heater
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CONSTRUCTION
The LU Models are constructed from 3mm galvanized steel cabinets complete with internal or external fan
motor drive, access doors and heavy base frames.
The GDH furnace is constructed from 1.0 mm galvanized steel and is basically an open ended duct with
galvanized iron frames on both ends for rigidity and ease of mounting; one extra angle iron frame is supplied
fitted to the air leaving end of the furnace for simple attachment to new or existing ductwork. A large quick
release access panel is fitted to the rear of the duct for easy service access to the burner. On the control
side of the duct, an inspection port is provided for flame observation.
Main Burner Assembly
The direct fired burner consists of a solid cast iron manifold frilled to suit the burner rating, fitted with
stainless steel flame retention plates specially formed to give excellent air gas mixing through the low to
high fire range and still achieving combustion results well within the limits of 10 ppm and 3000 ppm CO2
as laid down by Australian Gas Association (AGA) regulations.
The burner retention plates line up with a profile plate which is fitted around the inside perimeter of the
duct which also adds to the overall strength of the unit. When the air handling fan is turned on, air is
squeezed through the profile plate and over the burner providing an air velocity in the order of 12 –16
metres per second.
Burner Control
The programmed burner control system sets the sequence for lighting and supervising the flame. This
control provides the pre-purge sequence, energizing the ignition transformer which provides a high
tension spark at the tip of the ignition electrode. The controller energizes the pilot burner safety shut-off
valve (when pilot fitted) and main burner shut-off valves. Flame supervision is by signals directly back to
the burner control. No flame or a loss of flame will cause the burner control to lockout and shut off all
gas valves within 1 second. A red light will indicate when flame failure lockout) has occurred.
Valve Train
One or two separately controlled valve lines make up the valve train depending on whether a pilot is
fitted or whether direct low fire start is used.
a. The pilot line (when fitted) consists of a small gas cock, regulator and a solenoid valve.
b. The main burner line consists of a much larger gas cock, regulator, two safety shut-off valves and
a modulating valve.
Solenoid valves and safety shut-off valves will only operate on command from the burner control in
their correct sequence.
Safety controls
a. The air pressure switch connects in such a way as to detect air pressure differential across
the profile plate and will detect a fall in air volume over the burner.
b. The high limit switch mounted in the control box has a remote bulb which is field mounted
and will detect any abnormal increase in air temperature.

Installation Information
GDH Series Direct Fired Ducted Heater
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Installation Info rmation
The following recommendations are not intended to supplant or take precedence over any official
regulations, national or local, concerning the installation of the heater. Attention is drawn to regulations
concerning fire, gas, water and electrical installation to Australian and local codes practice.
BASIC INSTALLATION
Consult local building codes for special requirements e.g. gas supply, electrical supply, building computation.
1.1. Consult “Australian Gas Association Code for Installation of Gas Burning Appliances and/or
Equipment” (AG 5601) regarding the installation.
1.2. Notify local gas supply authority of you intention to install the direct fired heater and provide the
following details:
1.2.1. Burner data
1.2.2. Purge and critical time calculations.
1.2.3. Wiring diagram.
1.2.4. Valve train layout.
1.3. The heater should be installed by approved personnel only.
1.4. Ensure heater receives only fresh air from the source of supply. This type of heater must not have
any return air passing through the burner.
1.5. Like any total fresh air system, adequate relief must be provided, generally at the rate of 1 square
metre per 1000 litres per second of air supply. Should mechanical exhaust be the only form of
relief, exhaust system and heater air supply must be electrically interlocked.
1.6. Provide at least 600mm clearance at the front and rear of the heater for service access.
1.7. Should furnace be located in a plantroom ensure gas pressure regulator installation complies with
venting requirements.
1.8. Should ductwork on the discharge (leaving) end of the GDH heater be insulated, ensure insulation is
manufactured from non-combustible materials.
1.9. When adding the heater to existing registers and/or box diffuser is constructed from a material
capable of withstanding temperatures in the order or 80-90°C.
1.10. Ensure fresh air intake is clear of any flues, exhaust outlets, vent pipes etc.

Installation Information
GDH Series Direct Fired Ducted Heater
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EXAMPLE INSTALLATION
For the following example, assume the heater will be outdoor, roof mounted, with supply air from an
existing side discharge evaporative cooler for GDH models.
Inspect equipment to ensure correct model has been delivered. Also check for any possible shipping
damage and/or shortage and report any damage or shortages immediately.
2.1. Consider the best approach for installing GDH heaters.
a. Leave dropper duct and flashing in position and move cooler across to make way for heater:
Or
b. Leave cooler in position and move dropper duct and flash across to make way for heater.
2.2. Provide adequate support for heater in line with air supply between cooler and ductwork.
2.3. When using crane to lift heater, ensure an adequately sized rope sling is used. Do not sling around
gas valves or controls.
2.4. When installing weatherproof heater outside, ensure heater is kept horizontal to prevent rain
entering burner and controls.
2.5. Fit furnace onto stand, ensure air flow direction corresponds with cooler air flow direction, secure
heater to cooler and secure remaining end to ductwork and seal off.
2.6. If required, provide any necessary permanent access to appliance as required by regulations.
2.7. For control wiring provide 240 volt, 50 Hz power supply with appropriate neutral and earth. Mount
remote controls in heated are and wire back to heater.
2.8. Provide a gas supply to heater of adequate size and pressure. Refer to data pages to determine
pipe sizing.
2.9. Confirm commissioning gas and/or on-site inspection with gas authority.
2.10. Carry out start up procedures as detailed in Section 4. Obtain on-site inspection and approval from
gas supply authority.
2.11. Hand installation over to customer by explaining full operation of the system and the necessity of
regular maintenance and annual inspections as required by some State laws.

Installation Information
GDH Series Direct Fired Ducted Heater
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START UP
This start up should only be carried out by authorized personnel. Gas supply authority will require
notification of intention to start up the heater. These heaters are Class B appliances and require on-site
safety test which must be done in the presence of an inspector of the gas supply authority.
3.1. Check List
3.1.1. Ensure heater is installed correctly onto ductwork.
3.1.2. Ensure electrical supply and control wiring is installed.
3.1.3. Ensure gas reticulation is installed and supply pressures are within minimum and maximum
as stated on the data plate.
3.2. Start Up
3.2.1. Leave gas cock turned off. Turn selector switch to heat thermostat to maximum. Ensure sir
supply source is electrically interlocked with heater.
3.2.2. Fit a low scale manometer to air pressure switch by connecting high and low side of the
manometer to high and low pressure test points on air pressure switch. Turn heater on. Air
supply fan should run and provide a differential pressure between 110 Pa and 160 Pa.
When pressure differential is within this range, the burner should receive correct air velocity.
If differential pressure is low, adjust profile plate to increase pressure.
3.2.3. Pressure test gas valve train in the following stages:
Fit manometer to test point between isolating valve (gas cock) and heater valve train. Leave
gas cock closed –No pressure means gas cock is not leaking.
Pressure test between isolating valve and first safety shut off valve. Maximum test pressure
5 kPa.
Pressure test between both safety shut-off valves. Maximum pressure 5 kPa.
3.2.4. Remove access panel at rear of heater. Inspect main and pilot burner assemblies. Check
setting of ignition electrode.
3.2.5. For GDH heaters uncoil high limit capillary; Bulb must be located approximately 1 meter
away from burner and approximately two thirds up vertically inside the duct. Refit access
panel.
3.2.6. With gas cock still off, reset burner control. Allow burner to cycle through sequence for dry
run basically as follows:
1. Fan runs pre-purge approx. 30 sec
2. Pre-ignition approx. 3 sec,
3. Pilot solenoid valve open. No gas no pilot.
4. UV cell sights no flame or ionisation rod senses no flame. Lookout; Red light on burner
control (failed safe).
3.2.7. Check all electrical connections for tightness including remote control panel if fitted.
Check gas pipe fitting between burner and safety shut off valve for tightness.
3.2.8. Check gas pipe fitting between burner and safety shut off valve for tightness.
3.2.9. Ensure gas line to heater is purged of air, turn gas cock on, turn main burner test cock off.
Turn burner test cock on. Reset burner control. If unit is non-pilot version, open main gas
cock. Control Sequence is as follows:
1. Fan runs pre-purge about 30 seconds.
2. Pre-ignition about 3 sec.

Installation Information
GDH Series Direct Fired Ducted Heater
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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-CO2 combustion analyzer, check the CO-CO2 emission from the heater.
Burner must not produce more than 10 ppm CO and no more than 3000 ppm CO2 while still
maintaining a CO-CO2 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-CO2 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.

Operating Instructions
GDH Series Direct Fired Ducted Heater
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Operating Instr uctio ns
Operation is generally dependent on the installation control system, which can vary quite considerably.
Assume the system has all standard remote control options.
Step 1 Turn selector switch to heat.
Step 2 Set time switch (if fitted to omit days heater will not be in use, set on and off pegs at
required times, set current day and time.
Step 3 Set thermostat to the desired temperature.
Step 4 Should burner fail to operate and go to flame failure:-
a. Red light will become illuminated on lockout reset assembly.
b. Press reset button, hold for 1-2 seconds.
c. Burner should start.

Technical Information
GDH Series Direct Fired Ducted Heater
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Weatherproof
control
enclosure
Front access
panel
Power and
gas supplies
inside
enclosure Figure 1
Technical Infor mation
Technical Specifications
GDH Model
160
210
265
340
525
790
1055
1100
1500
1585
2110
2500
Dimensions / Weight / Configuration
A
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
B
610
762
915
990
610
762
915
1150
990
1150
1400
C
310
310
310
310
310
310
310
310
310
310
310
Weight
32
35
64
71
66
71
87
136
116
138
125
Dampers
No
Yes
Yes
Yes
No
No
No
Yes
Yes
No
No
No
Air Requirements
Min. l/s Cooling
2800
4000
6500
2200
4200
5800
10000
15000
8800
14500
20000
Max. l/s Cooling
4500
6400
9500
1500
2400
4400
14500
21000
6000
9000
15000
Min. l/s Heating
900
1400
2200
-
-
4500
7500
-
-
-
Max. l/s Heating
1400
2200
4500
-
-
7000
11000
-
-
-
Gas
Connection (mm)
20
20
20
20
20
25
32
40
40
40
40
40
Minimum kPa
7
7
7
7
7
7
7
7
7
7
7
7
Maximum mJ/h
160
210
268
340
525
790
1055
1100
1500
1585
2110
2500
kW @ 1.75 kPa
87
110
132
117
220
293
259
440
440
586
732
kW @ 1.12 kPa
58
75
94
100
148
176
172
293
293
390
-
LU Models Drive Details
Motor Type
Motor Power
Motor Pwr (kW)
Fan
Litres/Second
Controls