COMBAT® CABINET HEATERS INSTALLATION, COMMISSIONING, OPERATION AND SERVICE MANUAL
Figure 13: Combination Thermostat (all models)
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| Set Point 3 |
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| 120 | Limit |
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| Set to 110°C | |
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| 100 | |
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| 80 |
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| 60 |
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Set Point 1 | C° | 20 | 40 | Set Point 2 |
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Fan Off |
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| Fan On |
Set to 38°C |
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| Set to |
See Page 34, Section 10.2.5 and repeat until
the burner fires.
10.2.4 Initial Setting
NOTE: Skip this step for models 015 to 030.
Once firing, the start gas pressure should be set to the value given in the Data Tables for the burner type and the model concerned (see the burner reference letter on data plate). This is carried out by turning the governor adjusting screw (accessed under the black
10.2 Commissioning the Burner (gas heaters)
High/Low and modulating burners have additional specific requirements. Follow the manufacturer’s instructions using the data provided on Page 8, Section 4.4 through Page 10, Section 4.7.
10.2.1 Gas Supply
All aspects of the gas installation, including the gas meter, must be inspected, tested for soundness and purged in accordance with local and national codes. Ensure that the air is fully purged from the heater inlet pipe up to the main gas valve inlet test nipple.
10.2.2 Before Operating the Heater
Ensure the burner head, air damper and pressure switch settings are adjusted for the correct burner in accordance with the Data Tables on Page 8, Section
4.4through Page 10, Section 4.7 (see the burner reference letter on data plate).
To ensure that all the controls are in safe working order, operate the heater for the first time with the isolating gas valve turned off.
1.Turn off the gas isolating valve
2.Using the installed external control, turn on the burner. The automatic sequence will now begin as described on Page 35, Figure 14.
There will be no ignition of the burner and lockout will occur, which proves the controls are operating correctly.
10.2.3Fire the Burner for Dungs Combination Gas Valves
1. Open the gas isolating valve.
2.Connect a suitable pressure gauge to the burner pressure test point.
3.On models 040 or larger, to ensure that start gas only may pass to the burner, remove the gas valve electrical plug for the main gas valve.
4.Reset the lockout button of the control box and the burner should now fire. If lockout should occur when the start gas valve energises (or the main gas valve for models up to 030), repeat 3 or 4 times. If after several attempts the burner does not fire, then turn the start gas governor adjusting screw (or main gas gover- nor for models 015 to 030) 3 turns clockwise.
10.2.5 Set Gas Rate
1.Switch off and refit the main gas valve plug (removed earlier to allow the main gas valve to operate).
2.Switch on again and allow the burner to fire and to settle for a few minutes.
3.Adjust the main gas burner pressure to the value given in the relevant Data Table for the model concerned using the Main Gas Regula- tor (accessed under the swivel cover). See
Page 37, Figure 17.
The results of setting the gas flow rate by using burner pressure only can lead to quite wide variations in heat input due to the nature of the burners used.
NOTE: If the correct burner pressure cannot be reached, then check the inlet pressure to the valve, with the burner firing. See Technical Data Tables on Page 8, Section 4.5 for inlet pressure requirements.
Do not continue to adjust the regulator if the pressure is not changing.
If the inlet pressure is too low to allow the correct burner pressure setting, then the gas inlet pressure must be corrected before completing the commissioning.
10.2.6 Check Gas Rate
It is important to check that the gas rate set during the commissioning is within ± 5% of the required flow rate.
This may be achieved by checking the gas flow to the heater wherever possible by using the gas meter and timing the flow through the meter. The results should be compared with the required flow rate for the model given in the Data Tables, adjusting the burner pressure to correct for any error.
Checking the gas rate must be carried out with all other appliances including any pilots, turned off.
1.After burner pressure adjustment, allow the heater to operate for at least 15 minutes and then
2.Remove the manometer and refit all covers to the valve and tighten the screw of the outlet pressure tap.
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