Patterson-Kelley MACH-05 manual Loss of Water Level, Low Gas Pressure, Low Air, Air Switch Closed

MACH® Series Gas-Fired Boiler Maintenance

Loss of Water Level

The low water switch opens when there is insufficient water level in the boiler. E 12 is shown on the display, and burner operation is interrupted. When the correct water level is re-established, pushing the reset button will return the sequence to Step 5, provided that the other limits are satisfied.

Low Gas Pressure

The low gas pressure switch opens when there is (or has been) insufficient gas pressure available for proper operation of the boiler; E 12 is shown on the display, and burner operation is interrupted. If a gas-supply shut-off valve is closed for any reason, a low gas condition will result.

When gas pressure is restored, E 12 will remain on the display panel, and the boiler will remain locked out until the front panel reset button is pressed.

Once the control is reset, the sequence returns to Step 5, provided that the other limits are satisfied.

manually reset and the front panel reset button is pressed. Once the switch, and the front panel are reset, the sequence returns to Step 5, provided that the other limits are satisfied.

Low Air

If the display panel indicates E 08 this indicates insufficient airflow through the burner. Check that the burner is clean ("Cleaning the Burner," Section 5.2) and that there are no obstructions to airflow in the intake or exhaust ducts. A low air indication does not necessarily mean that the low air switch is defective.

Air Switch Closed

If the display panel indicates B 61 this indicates the air pressure switch did not open when the blower was shut off. Check that there is no air flow through the boiler when the fan is off. If there is no hidden source of air flow, replace the switch.

High Gas Pressure

The high gas pressure switch opens when there is (or has been) excessive gas pressure for the proper operation of the boiler. An E 12 service code is displayed and the burner operation is interrupted.

When proper gas pressure is restored, E 12 remains on the display with the boiler locked out until the front display panel reset button is pressed.

High Water Temperature

When the boiler water has exceeded both the operating and high-limit temperature the high limit switch opens, and E 12 is shown on the display. When the water temperature falls below the high-limit temperature, the boiler will remain locked out until the switch is

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Flame Failure

In the event of a flame failure during a firing period or a trial for ignition, the main fuel valves are de- energized and a manual reset lockout occurs. After the spark ignition is re-energized, the 3 second trial-for- ignition begins again. If flame failure occurs during a trail-for-ignition, a safety lockout occurs. The display will indicate E 02. If flame failure occurs and an service code is displayed, the combustion control must be manually reset.

E 00 signifies a leaky gas valve. In the event of a false flame signal E 00 fault code is indicated. This fault code could indicate a gas valve failure or leakage of the gas valve. If gas valve leakage is suspected, the unit must be isolated by turning off the main gas supply line until the gas valve is replaced.