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Seamless Customer Operation, Installation and Servicing Information

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Certificate Number: 8107
Date of Issue: 5 Sept 2014

Brand Name:   Heatmaster
Model/s:   Inbuilt Seamless
Description:   Induced draught, luminous and heating power flue effect, mains power 240V AC
High efficiency gas log space heater
This appliance is for use with Natural Gas.
Certificate Holder:   Heatmaster Pty Ltd.
2/9 Nicole Close, Bayswater, Victoria, 3153, Australia
ABN:   64 641 709 587
Contact:   (03) 9761 7134
Manufacturer:   Heatmaster Pty Ltd.
2/9 Nicole Close, Bayswater, Victoria, 3153, Australia
Contact:   Tel. (03) 9761 7134
ABN:   64 641 709 587
Distributor:   Heatmaster Pty Ltd.
2/9 Nicole Close, Bayswater, Victoria, 3153, Australia
Contact:   Tel. (03) 9761 7134
ABN:   64 641 709 587
Australian Standard:   AS 4553 – 2008 (incorporating amendment No 1) “Gas space heating appliances”




General Description

Gas System
Heating System





Rear View Balanced flue with 58 and 65mm Ø. Pipes

Horizontal and vertical flue setup

Log set up




General Description

The Heatmaster “Seamless” Log space heater is an induced draft, high efficiency, fan assisted space heater with a Remote Manual/ Automatic thermostat control, using a 2 step High- Low gas setting. Low is front burner and high is front and rear burners together. If decorative mode is selected, only the front burner will ignite and the convection fan will not operate.

The heater gas safety functions are controlled by an AGA approved electronic flame supervision and ignition controller. This controls the combustion fan, and fan operation is proven by a Cleveland Control duel pressure switch.

A separate Millennium branded controller handles all other functions including temperature sensing and control of convection fan speeds Low, High and Off if decorative mode is selected with only the front burner on. It also communicates with the RF remote.

As well, the two convection fans are enabled by a thermal sensor adjacent to the heat exchanger, once the firebox has reached operating temperature. The actual fan speeds are selected from the remote and also modulate automatically in steps (Hi-Low) when required.

Safety features included are:

Flame failure and overheating safety system, automatic shut down if gas or power failure occurs and fan start-stop protection. On startup the combustion fan runs at a higher speed than normal to automatically purge any unburnt gas prior to ignition. A glass dress guard is fitted to the heater door to prevent accidental mishaps.

The Heatmaster Seamless Gas Log space Heater is a room sealed heater that can be installed in three configurations. The maximum length of flue and air supply pipe is 12 meters.

  1. Fitted with two pipes vertical. A 60mm pipe to supply external air and a 50mm flue pipe to expel combustion products via a balanced flue terminal
  2. Fitted with a horizontal balanced flue configuration. A 60mm pipe to supply external air and a 50mm flue pipe to expel combustion products via a balanced flue terminal.
  3. Fitted with a combination of vertical and horizontal twin pipes suspended under floor. A 60mm pipe to supply external air and a 50mm flue pipe to expel combustion products via a balanced flue terminal


The unit is started by the remote control.

The SIT 590DBC starts the combustion fan. The millennium control ramps the fan speed to a higher setting for 30 seconds to ensure pull in of the pressure switch and to perform a thorough purge. The pressure switch proves the combustion air and enables the 579 to proceed to start-up. The combustion fan reverts to a lower operating speed for quietness.

The front burner will ignite first in every case, and the flame detection of this burner is verified by the SIT 579 in approx 5 seconds. After 40 seconds from start up, and only after the front burner has ignited and satisfied the SIT 579 that it has flame, will the second burner and thermostatic operation be enabled. An interlock in the SIT 579 control ensures this.

If decorative mode is selected, the unit cannot progress to the second burner stage or any room fan setting. IE there is no room fan or second burner available in decorative flame mode.

If/when extra heat is required, as decided by the user or the thermostat, the remote control/main control will allow the second solenoid valve to supply gas to the rear burner, provided the decorative (front burner) is burning. This burner will ignite by cross-lighting from the front burner. Only the rear burner modulates on-off depending on thermostat for temperature control. The decorative only burner will not modulate OFF until switched off by the user or built in timer.

The second solenoid for the rear burner can only be activated when the signal from the SIT 5479DBC confirms flame at the front burner. The power supply for the rear burner solenoid is provided from the flame signal of the SIT 579, so the power to the rear burner cannot be applied from any other source. This setup ensures absolute safety in that the rear heating burner cannot be supplied gas spuriously. The solenoid valve for the second burner is also a tandem double block approved valve.






Heatmaster, Inspiration type Rectangular Bar Burner

SIT , double block , 840

SIT, Electronic , 579DBC

SIT , double block , 840
Dungs double block valve for high setting.

SIT , double block , 840

Everburn, Ceramic Compressed Kaowool , Heatmaster Seamless

1. Vertical twin pipe through the roof and connected to a balanced flue terminal.
2. Horizontal twin pipe through the wall and connected to a balanced flue terminal
3. Combination vertical and horizontal twin pipes suspended under floor and connected to a balanced flue terminal
Note: The flue length must not exceed 12 meters.

OPTIONS (Test Laboratory Assessed)
Must be installed on a fireproof base.
The following clearances from combustible materials must be observed: Above 300mm. Sides 12mm. Rear 10mm

Gas Type: Natural Gas @ 0.88kPa Test Point Pressure*
Burner Injector Size (mm) N.G.C. (MJ/h)
Minimum. Front burner:
1.95 Injector size (mm), 18 N.G.C. (MJ/h)
Maximum. Both burners:
1.95 Injector size (mm), 36 N.G.C. (MJ/h)
* The test point pressure is set with ‘both burners’ on maximum. BURNERS are ON – OFF only

Dimensions / Weight:
Heatmaster Seamless Inbuilt
Width 1295mm
Depth 495mm
Height 465mm
Weight 85kg

Star Rating
Model: Heatmaster Seamless
4.0/4.2 Stars (Flue dependent)



The Heatmaster Seamless Gas Log Heater comprises of a metal fire box structure and a Heat Exchanger located within an outer casing, which has a transparent ceramic glass front door.

The heat exchanger includes a primary heat exchanger (firebox) subject to gas heating, a secondary heat-exchanger made of tubular members heading from the firebox and connecting to the inlet header of the manifold flue fan box. The secondary heat exchanger is made of corrugated flexible stainless steel tubes, which are connected at their other end to the combustion fan, so as to extract and expel the combustion products from within the firebox, the tubular members and the manifold box.

The combustion products are expelled to the atmosphere by the combustion fan through a flexible aluminium flue system of 50mm diameter to a balanced terminal.

Two convection room fans are positioned at the bottom of the fire box structure so as to draw cool air from the room through an opening at the lower end of the firebox fascia this air is heated by passing through the outer surfaces of the primary and secondary heat exchanger’s and finally expelled into the space being heated. The double convection fans are so situated, that it provides a cooling effect on the working components, such as combustion fan and adjacent electronic controls. The cooling effect is not necessary in decorative mode and the convection fans do not operate.

The firebox is made of 3 pieces of 1.2mm thick Aluminized steel sheet, press folded and assembled and joined by TIG/MIG welded construction.
The burners are fastened to the firebox assembly by two locating slots and 3.2 mm screws located at each ends of the burner tray.

The front of the firebox is sealed with the door frame made of one piece of 2.5 mm thick mild steel sheet, pressed and folded. The door is sealed with a 19mm Ø. fiber glass rope and a fiber glass tape around the 5.0mm Ceramic glass edges. Four M6 x 35mm screws mount the door assembly on the firebox and maintain it in place firmly and gas tight. The external outer panels and fascia are made of pressed and folded 1mm thick Aluminized Steel. The external front trim is aluminum.

Refer Drawings HMR-716-206,213,215,216,217,218,227,228,229 & 230

Primary Guard

The primary guard is 5.0mm Ceramic glass approximately the size of the door assembly. It is hung on supporting brackets at each end, is approximately 20mm from the door glass and is removable for cleaning etc. It allows convection between the glass and the door for cooling of the guard. The edge gaps preclude the temperature test cone as per AS4553

Refer Drawings HMR-716-201,262 & 263

Primary Air

The primary Air for combustion is drawn into the firebox through a 60 mm pipe of 1.6mm mild steel attached to the firebox back side air inlet hole opening of 60 mm diameter

Refer Drawing HMR-716-212

Combustion Chamber

The Combustion Chamber is made of 1.2mm aluminized steel with the burners sitting inside the firebox elevated from the bottom. The rear and front rails and the 2 burners separate the bottom and top halves into combustion chamber on top and required secondary air for the correct combustion and flame pattern in the bottom. The bottom space is connected to the air inlet on the back of the unit. The volume of the firebox is 92 litres including the volume of the logs. The internal top rear corner of the firebox, from where the combustion gases are evacuated is covered by a baffle made of 1.6mm aluminized steel to restrict the flow of flue gases and to protect this area from the intense heat.

Refer Drawing No. HMR-716-206,209,229 & 230

Primary Flue Connection

The primary flue connection is made of a 50mm N.B. aluminum flexi tube made by Abbey and attached to the back of heater by a 50mm hose clamp.

Flue Cap

See Appendix 3. Flue Cowl Assembly

Refer Drawing No. 043


Gas Piping

To bring the gas supply, the inlet gas pipe consists of a 12.7mm Ø. by 400mm long corrugated flexible stainless steel pipe manufactured by Dormont America, the other end of the pipe is connected to the Sit gas valve, which delivers the gas to the injector burner (front and rear) by using copper pipe and manifold of ½” mm Ø and 3/8” Dormant corrugated tube.

Gas inlet connection

Gas inlet fitting is a ½” BSPM plated steel fitting supplied with the ½” Dormont Pipe. This connection is located at the rear left bottom corner of heater.

AGA Approval No. 5531

Gas Control

SIT ,Model SIT 840 Type Gas Valve

  • Maximum working pressure 5 kPa
  • Temperature Limitation 60°C Maximum
  • 220-240V / 50-60Hz
  • Inlet connection: 1/2″ RC series (AS 1722.1)
  • Outlet connection: 1/2″ RC series (AS 1722.1)

The SIT 840 valve incorporates the following features:

  • 1 individual gas outlet controlled by double block solenoids
  • Two automatic shut off valves – AS 4624 Class 2 and 3

AGA Approval No. 5733

Pressure test point (Burner)

8.9mm Ø Brass Nipple with removable screw and washer, located lower left front of the heater accessible at all times. The test point is remote from the gas train and connected by small bore copper tube to the main gas manifold.

Refer Drawing No HMR-716-250

High burner solenoid

This is an AGA approved EBM double block gas valve without regulator and can only be powered from the SIT control after flame is successfully sensed at front burner.

Model No: GB-D 055

AGA Approval No: 7858

Alternate, Kupo valve

AGA approval No: 8054


Length: 35.5mm
Diameter: 10mm
Thread: 1/8 BSP male

Refer Drawing HMR-716-214

Burner Details

The Heatmaster Seamless series heaters utilise a two bar burner assembly mounted at the bottom of the firebox, below the ceramic logs mounting tray.

Burner ‘Front’ bar

This burner is a single piece 50 X 20mm X 1.5mm RHS mild steel construction and with an inspirator tube 20mm SHS welded at right angles to, and under the burner body.
Ports are drilled.

Primary air is drawn through a single 5 mm Ø hole in the inspirator tube.

The burner is NOT interchangeable with the rear burner and cannot be incorrectly located.

Refer Drawing No. HMR-716-220,221,222 & 223

Burner ‘rear’ bar

This burner is a single piece 50 X 20mm X 1.5mm RHS mild steel construction and with an inspirator tube 20mm SHS welded at right angles to, and under the burner body.

Ports are drilled.

Primary air is drawn through a 7.5mm Ø hole drilled through both sides of the inspirator tube.
The burner is NOT interchangeable with the front burner and cannot be incorrectly located.

Refer Drawing No. HMR-716-224,225



Induced draught power flue, fan assisted convection with flame effect.


Everburn, Ceramic Compressed Kaowool Log set. See Photos Page 17 & 18 for location. Location lugs ensure correct placement

Warm air outlet

Located in top front of heater above fire box.


Electrical Details

A 240 volt ignition is used on this appliance.

Burner controller

SIT, Model 579/571 DBC TW -35S TS-5S.
Maximum temperature: 55C
Power rating: 220-240Vac / 50-60Hz
Spark gap: 3.0mm
AGA Approval No. 7358

Ignition Box

Same as above

Ignition Switches


Spark Plug

Spark igniter on front burner bar,
Techrite part # 07714392
Firing Tip Material: Inconel


Ignition Module & Ignition Switches
Maximum temperature: 60C
Power rating: 220-240Vac / 50-60Hz

Spark Plug Leads
Teflon or silicon rubber coated
Maximum temperature: 280C
Power rating: High tension Wire

Power cord

2 metres Flex standard 3 pin plug 10 amp, brand Castle Electronic, or equivalent approved cord set.
Conform to AS3100 240V 50Hz
Maximum temperature: 120C
Power rating: 220-240Vac /7 Amp 50-60Hz

Room Fan

2 Cross flow fans , TORIN FTZ180 single phase shaded pole motor Maximum temperature: 90C
Windings thermally protected inherently (inductive reactance.)
Power rating: 50W 240Vac / 50Hz

Flue Fan

FIME (induced draft), model number. GR-03455
Temperature range: 0C to 100C
Maximum Winding temperature: 180C
Power rating: 220-240Vac / 50-60Hz

Pressure switch

Cleveland Control, model number.NS2 -1088-00 set at 50 Pa.
Temperature range: -40C to 88 C
Power rating: 5 Amp @ 220-240Vac / 50-60Hz

AGA Approval No. 7290

Over temperature switch

Techrite model T24A180BXR2-15, Bimetallic N/C Auto-reset cut-out 180C 10Amp – 250 V a/c.

Room Fan thermistor controller

150C thermistor epoxy body made by Millennium Electronics
Rated at 100Kohm @ 25C

Millennium control

Millennium electronics control: 5200-0153-01A maximum running temp 65C



The Heatmaster Seamless Gas log space Heater has been designed for a simple and efficient operation with the use of remote control.


Prior to operating the heater, ensure that the flue terminal is not obstructed furthermore, make sure there are no combustible objects leaning against, resting on, or within the immediate vicinity of the unit. Check that the heater main power and gas supply are connected and switched on.


The Seamless is operated by the remote controlled thermostat unit.

For complete remote operating instructions refer to attached Thermostat manual included with this heater.

But here are some basic instructions so you can override some functions to operate your heater.

1. To ignite your heater simply press the ON/OFF power button. The heater will automatically start the ignition sequence within approximately 30 seconds of self-checking and the heater will ignite.

2. The fan will not start until the heater has reached the minimum operating temperature. To select fan speed or the heat setting press the up or down buttons in the remote controller, to decrease or increase differential temperature between room and thermostat and flame and fan speed will be increased or decreased as desired. The fan will not operate at all in decorative flame mode.

3. If you wish to switch between flame only (decorative) and heating mode, simply press the A/M button on the remote control.


Press the on / off switch once. The room fan will continue to operate for a short period while the heater cools down.
Please note:

1. Due to the performance and efficiency of the heater, steam may be noticed coming from the flue terminal on cool days

2. As this appliance has a luminous effect some slight carbon deposition may occur in the logs.

3. During first time firing of this appliance, an odour may be noticed for a short period as the paint cures. It is advisable to leave the windows open during the first few hours of the very first operation only.



! DO NOT place articles or clothing on or against this appliance
! DO NOT use or store flammable materials near this heater
! DO NOT place any item containing liquid on the heater
! DO NOT spray aerosol in the vicinity of this appliance when it is in operation
! ALWAYS supervise young children near the appliance
It is recommended that a secondary guard be used, to prevent access to appliance by children, as outer panels of this appliance may reach high temperatures.

NOTE: In the event the electricity supply cord is damaged it must be replaced with the original Heatmaster part obtainable from your authorized dealer.

It is recommended that a general service be carried out every 12 months to ensure the optimum operation of your Seamless fire.

For servicing, or parts replacement parts contact your Heatmaster dealer




*Do not modify this appliance

WARNING : Before you do any attempt to service the heater be sure that electric power plug has been disconnected.

This heater should be serviced at least once a year to clean the Room Fans from lint and dust accumulated in the air ducts and unit.

This heater does not require to be removed to service and maintain any items such as logs, gas valves, room fans, electronic control components.

The unit does not require disassembly to access the gas pressure test point.

The gas regulator test point is accessible after removing the front glass guard and the test point will be visible at the front lower left hand side of the unit.

The unit does require access into the combustion chamber to adjust the gas regulator through the back wall of the chamber.

The gas adjustment for the regulator is accessible after removal of the main inner door and the left hand logs. There is provided a small access panel that can be opened and a long series flat bladed screwdriver can be inserted through the hole and into the regulator screw of the SIT control valve.


To service the main items listed above it is necessary to remove the Combustion Chamber.

Disassemble in this order:-

1. To access the logs and burner components. Remove the outer door glass guard and undo the four screws that hold the door. Two at the top of door frame where the hot air outlet is and two at the bottom of door above the room air inlet.

2. Remove the logs and store safely.

3. The burners can be removed by removing the screws (visible each end of the unit) holding the Burners and cover plates. The igniter electrodes can be removed by undoing the 2 retaining screws on the front burner.
Remove the front and rear covers and then remove the burners by slipping them forward and upwards together.

4. The heat exchanger is held by 2 screws in the bottom of the burner box. Remove these.

5. Remove the top angled baffle at inside top/rear of combustion chamber by removing the screws and spacers taking note of the spacers at the front of the baffle.

6. There are 8 nuts visible that must be removed to release the internal flue connection. Ensure that gasket is not damaged in this removal, or that gasket is replaced upon re-assembly.

7. At the bottom rear of the combustion chamber, each side of the air inlet hole there are 2 screws visible. Remove and observe sealing gasket condition as above in (6.|)

8. Remove combustion chamber by lifting and pulling forward.

9. The main components are concealed in sealed insulated boxes each side of the heater. NOTE: the gas components are in the LHS box as viewed from front, and the electronic controls are housed in the RHS box. There is one room fan in each box, total of 2.

10. To access these components carefully remove the top insulation of the desired box, and undo the screws holding the box lid. Note that there are rubber diaphragm gaskets for the fan. These are flexible and do not require removal. Lift off lid and access the components. It may be necessary to remove one or both corrugated heat exchanger tubes for ease of access.

11. The main control box is mounted in the RHS box on a bracket along with the pressure switch. There are screws holding this bracket to the unit floor. As well the main gas SIT control box is mounted adjacent to this bracket. The room fan(s) are similarly mounted on brackets. Ensure that all brackets and insulating bushes are re-assembled onto new fan if not provided with the fan. Ensure that all wires and hoses are marked for ease of re-assembly as unit will not test out unless fully assembled.

12. The gas components are mounted in the LHS box. Most connections are flare jointed for ease of disassembly. The wiring is polarised to prevent misconnections, as are the fan plugs.

13. Re-assemble unit in reverse order taking care that:-
a. The component boxes are re-sealed and insulated.
b. Any gasketing is in good condition or renewed with factory supplied gaskets or material.
c. All screws firmly tightened.
d. Unit is gas-leak tested.
e. Unit is fired up for final check and gas burner pressure checked and reset if necessary.

Note the power cord supplied must not be replaced

Caution: The right way to put down the front glass panel

modern B series open wood fireplace


The outer glass is fitted to this appliance to reduce the risk of fire or injury from burns and it should not be permanently removed. This glass still gets very hot and therefore, for protection of young children or the infirm, a secondary guard is required.

contemporary design Seamless gas fireplace easy install

Tempered Glass – Heat strengthened for safety, tempered glass is approximately four times as strong as standard glass. In the event of breakage tempered glass fractures into small particles which do not form sharp edges. This greatly reduces the chance of personal injury.

As a result, it’s important to check and report any imperfections prior to installation.




  • Appliance fails to ignite.


  • No gas or supply pressure insufficient.
  • No electrical supply.
  • Incorrectly wired power point.
  • Incorrect gas valve adjustment.
  • Insufficient time allowed between attempts.
  • Internal wiring disconnected.


  • Ensure gas supply connected, purged, and pressure appropriate.
  • Ensure unit plugged in and switch is on, check supply fuse.
  • Check supply. Active, neutral, & earth must be correctly orientated and connected.
  • Adjust valve pressures.
  • Wait at least 30 seconds for unit to purge combustion chamber after switching on.
  • Check all plugs inside appliance are connected properly and correctly located, Ensure operation of combustion fan & air pressure switch.


  • Unit will not operate on Low.


  • Incorrect gas valve adjustment.
  • Incorrect or loose wiring.


  • Adjust valve.
  • Check wiring.


  • Room fan not operating.


  • Insufficient time allowed.
  • Loose wiring.
  • Fan not located correctly.
  • Fan blocked.


  • Fan has a delayed start and will not start until unit warms-up.
  • Check wiring.
  • Install fan in correct location.
  • Remove and clean fan.


  • Unit cuts out after a period of time then cycles on and off.


  • See “Room fan not operating”
  • Heat exchanger blockage.
  • Excessive pressure or incorrect gas type.


  • See “Room fan not operating”
  • Clean heat exchanger.
  • Ensure correct gas type, injector size, and pressure setting.


  • Excessive carbon (soot) deposits on inside of firebox, logs, and/or glass.


  • Incorrect gas type or pressure setting.
  • Primary air shutter incorrectly adjusted for gas type.


  • Ensure correct gas type, injector size, and pressure setting.
  • Adjust primary air shutter.


  • Excessive flame height.


  • Incorrect gas type or pressure setting.


  • Ensure correct gas type, injector size, and pressure setting.


  • Excessive flame “lift off”


  • Flue or inlet blockage.
  • Recirculation of flue gases.


  • Clear blockage.
  • Flue incorrectly installed.


  • Unit fails to heat.


  • See “Room fan not operating”
  • Incorrect gas type or pressure setting.
  • Gas supply blockage.


  • See “Room fan not operating”
  • Ensure correct gas type, injector size, and pressure setting.
  • Check injector, burner supply pipe, & valve for foreign matter.

All service work to be carried out by a qualified & authorised person.



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Heatmaster Seamless Data Plate



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Horizontal and vertical flue setup



Log set up

Log Set Arrangement

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Empty Fire box

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Rear left log in position

contemporary design Seamless gas fireplace easy install

Left & center rear logs in position

contemporary design Seamless gas fireplace easy install

Left, center & right rear logs in position

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Front left log in position

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Front left & right logs in position

Seamless landscape gas fireplace body

Two small logs complete the log set



As a purchaser of this Seamless product, Heatmaster (Aust.) Pty.Ltd. provide you with the following warranty:

Firebox ___________5 Years _____________1 Year free labour

All other Parts____________1 Year _______________1Year free labour

This Warranty is in addition to all other rights and remedies, which the purchaser may have under statute.

Note: Glass or logs are not covered against accidental breakage

Please select a state

  • VIC
  • NSW
  • SA
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