Patterson-Kelley MACH-05 manual Test of Low Water Cut-out, Test of High-LimitControl

MACH® Series Gas-Fired Boiler Installation

3.Smoothly close the downstream manual isolation valve to reduce the gas flow and cause flame failure.

4The display will flash E-02indicating a flame failure. The E-02lockout will remain until reset on the display.

After completing this test, turn off the boiler and open the downstream manual isolation valve.

3.11.2 Test of Low Water Cut-out

The boiler is furnished with a probe-type low water cut-out in the outlet nozzle. Test as follows:

Operation of the switch can be checked by first turning the boiler off, and then turning the system pump off. Isolate the boiler from the system pressure. After isolating the system, drain the water level below the low water cut-out probe. Turn the boiler back on. It should not operate, and a manual reset lockout displaying E 12 on the display panel will occur. The LED indicator for Low Water cut-out will no longer be illuminated.

Return the system to normal operation and restart the boiler. Refer to Section 4.2.1.

3.11.3 Test of High-Limit Control

Fire the boiler and test the high limit control as follows:

With the main burner operating, turn down the temperature setting on the "high-limit" thermostat until the main burner shuts off. A manual reset lockout displaying E 12 on the display panel will occur. The high-limit switch must be manually reset prior to resetting the boiler at the display panel. Readjust the high-limit thermostat to the desired setpoint.

3.11.4 Test of Gas Pressure Switch

Low Gas Pressure Switch

The boiler is furnished with a low gas pressure switch. The operation of this switch must be checked by slowly closing the main gas cock while the burner is operating. The switch should shut down the main

burner. When the gas pressure switch opens, a manual reset lockout displaying E 12 on the display panel will occur. Upon re-opening the main gas cock, the E 12 indicator will remain on until the display panel is manually reset.

High Gas Pressure Switch

C450 units equipped with a high pressure switch must be checked by closing the downstream gas cock while the burner is operating. The switch should shut down the main burner. When the gas pressure switch opens, a manual reset lockout displaying E 12 on the display panel will occur. Upon re-opening the gas cock, the E 12 indicator will remain on until the display panel is manually reset.

C750,C900 and C1050 units equipped with a high pressure switch must be checked by closing the downstream gas cock with the boiler off. When the boiler is starte , it should enter its normal starting cycle and fail on high gas pressure when the gas safety valves open. The high gas pressure switch actuation is evident when a manual reset lockout displaying E 12 on the display panel occurs. Upon re-opening the gas cock, the E 12 indicator will remain on until the display panel is manually reset.

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