COMBAT® CTU UNIT HEATERS INSTALLATION OPERATION AND SERVICE MANUAL
Figure 12: Gas Valve for Heater (Models 75 - 115)
Plug for |
|
Main Gas Valve |
|
Regulator |
|
(Under Cover) |
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| Plug for |
| Main Safety |
| Gas Valve |
Inlet Pressure |
|
Gas Inlet |
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Outlet Pressure | Gas Outlet |
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11.4.2Commissioning the Gas Valves (all gases) 11.4.2.1 Check Burner Gas Pressure
1. Loosen the screw cover of the outlet (burner) pressure test point and connect a manometer.
2.With the burner firing, measure the pressure on the manometer. To adjust the burner pressure, remove the regulator cover from the valve and turn the regulator adjustment screw to set the required burner pressure as stated in the Tech- nical Data Tables for the correct gas and model on Page 8, Section 4.4.
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 4.4 for inlet pressure requirement.
Do not continue to adjust the regulator if the pressure is not changing.
If the inlet pressure is too low to allow correct burner pressure setting, then the gas inlet pressure must be corrected before completing the commission.
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
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 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.
Pressure Switch:The pressure switch is factory pre- set for each model and is not adjustable.
11.6 Turning Off the Heater
Set the external controls to the off position and the main burner will stop.
The fans will run until they are stopped automatically by the fan thermostat.
Do not use electrical isolator for control of heater. Electrical isolator will switch off the fan. Heat exchanger could be damaged. Warranty will not cover damage to the heat exchanger if operated improperly.
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