SECTION 11: COMMISSIONING
11.4.2 Commissioning the Gas Valves
All DualAir® units are fitted with fully modulating burner operation. The Honeywell automatic gas valves are fitted with the Honeywell Modureg modulating regulator.
See Page 22, Figure 13.
The Modureg device provides the adjustments for maximum and minimum firing and is set using the
two adjustments. See Page 22, Figure 13.
The external control will operate the burner between these two limits depending on heat demand.
The minimum set point must not be set lower than the minimum burner pressure stated on Page 6, Section 4.2.
11.4.3 Commissioning the Gas Valve
There are two stages to commissioning the modulation equipment.
The minimum pressure setting must be adjusted first, any adjustment of the minimum pressure setting will affect the maximum pressure setting.
For ON/OFF
11.4.3.1 Set Minimum Pressure
1.Disconnect the leads from the coil of the Modureg regulator.
2.Connect a suitable manometer to the burner pressure test point of the main gas valve.
3.Turn on any external controls and allow the burner to fire for at least five minutes.
4.Remove cap and using a suitable 9mm span- ner adjust the burner minimum set pressure to the value shown on Page 6, Section 4.2.
11.4.3.2Set Maximum Pressure (Not Required for ON/OFF burners)
1. Press in the moving shaft of the Modureg valve and hold in this position while adjusting the burner maximum pressure to the value shown on Page 6, Section 4.2.
For adjustments See Page 22, Figure 13. NOTE: If the correct burner pressure cannot be reached, then check the inlet pressure to the valve, with the burner firing. See Page 6, Sec- tion 4.2 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 a correct burner pressure setting, then the gas inlet pres- sure must be corrected before completing the commission.
2.Release the moving shaft and observe that the burner pressure returns to the minimum setting.
3.Turn off the external controls and reconnect the electrical leads to the Modureg regulator.
4.Turn on the external controls and allow the burner to fire once again observing the burner pressure.
5.Using the temperature set point device of the installed control system, set for maximum burner firing and observe that the burner pres- sure slowly rises to the maximum as set.
6.Reset the temperature set point by small steps until the burner pressure slowly drops to the minimum pressure set. Repeat Step 5 and observe that the maximum set point is again
achieved.
Check Gas Rate
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.
3.Check gas flow rate at gas meter.
11.5 Combustion Testing (all models)
The only adjustment to alter combustion performance is burner pressure. Combustion quality must be tested to prove correct heater operation. Incorrect results will indicate faults with the installation or appliance.
Combustion testing must be carried out at full fire with all covers in place. The flue gas is sampled in the flue, within 1 meter of the heater. The values of CO2 should be between 6.5% to 8.0% for natural gas and 7.0% to 9.1% for LPG dependant upon model.
The CO will be up to 80 ppm (0.008%) dry, air free dependant upon model. Temperature rise of the flue gases above ambient should be approximately 160° C to 180° C. Seal test hole in flue after testing.
Following the above operate the heater for 30 minutes at the minimum firing rate. Following this time the temperature of the products of combustion in the flue should be measured. If the flue products temperature is below 80° C then the minimum firing rate should be increased. Continuous operation of the burner with flue gas temperature of below 80° C will cause condensation to form in the heat exchanger and flue system. This will cause nuisance water collection and a shortened heat exchanger life.
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