Burnham V8 Series manual Jumper

Figure 20: Wiring Diagram, Steam, McDonnell & Miller PS-801 Probe LWCO for Beckett Burners

BOILER SEQUENCE OF OPERATION WITH PROBE LWCO

When the thermostat calls for heat, it energizes the cad cell primary control, bringing on the burner. The burner will operate in the following sequence: Prepurge for the first 10 seconds; fire until the thermostat is satisfied or the limit setting on the high limit is reached; post-purge for the last 10 seconds. When the high limit control restores the circuit on a drop in pressure, the burner will start if the thermostat is still calling for heat.

The probe low water cut-off will shut down the burner after a 10-15 second delay, if the water level in the boiler drops below the probe level.

The probe low water cut-off will reset and restart the burner with a call for heat a few seconds after the water is re- turned to its normal level.

On burner start, if the cad cell does not see flame within approximately 15 seconds, primary control will shut burner down and enter into a recycle mode, after 60 seconds burner will restart and repeat trial for ignition. If after three

(3)trials for ignition, flame is not detected, control will enter into restricted mode and must be reset manually before burner can be restarted.

When there is no demand for heat, the operating control will maintain the boiler water temperature at the selected set- ting for proper operation of the domestic water heater, if equipped with optional tankless heater.

McDonnell & Miller PS-801

Terminals May Be Lettered or

Numbered as Follows:

Wire	Numbered	Lettered
Color	Terminals	Terminals
RD	5	B
BK	1	H
WH	2	N
Jumper	1-3	H-C

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