Mcdonnell & miller, Step 2 - testing – Xylem MM 714C Replacement Pump and Burner Switch Arm Contacts with Terminal Panel User Manual

Page 4

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STEP 2 - Testing

a. Turn on power to boiler and pump circuits.

With the boiler empty, the pump should turn on (5 or 5-M switch models) or the valve open
(7B or 7B-M switch models). The burner should remain off and boiler should begin to fill with water.

b. For Automatic Reset Models

When water level in the gauge glass is approximately 1 3/8” (35mm) above the horizontal cast line,
the burner should turn on.
For Manual Reset Models
When water level in the gauge glass is approximately 1 3/8” (35mm) above the horizontal cast line,
press the manual reset button and the burner should turn on.

c. For 5 or 5-M Switch Models

When water level in the gauge glass is approximately 2 1/8” (54mm) above the horizontal cast line,
the pump should turn off.
For 7B or 7B-M Switch Models
When water level in the gauge glass is approximately 2 11/16” (68mm) above the horizontal cast
line, the valve should be closed.

d. With the water in the boiler at its normal level and burner on, SLOWLY open the blow-down valve

until it is fully open. As the water level in the gauge glass begins to drop, verify that the following
occurs.
For 5 or 5-M Switch Models
When water level drops to approximately 1 1/8” (29mm) above the horizontal cast line, the pump
should turn on.
When water level drops to the horizontal cast line, the burner should turn off.
For 7B or 7B-M Switch Models
As the water level drops, the valve should begin to open.
When the water level drops to approximately 7/8” (22mm) above the horizontal cast line, the valve
should be full open.
When the water level drops to the horizontal cast line, the burner should turn off.

e. Close the blow-down valve after burner turns off and restore water level to normal operating level.
f. Repeat testing procedure several times to ensure proper operation of control.
g. After testing and verification of control operation, the boiler can be returned to service.

– Dimensions shown are typical.
– The following testing procedure is only meant to serve as a verification of proper

operating sequence.

CAUTION

Immediately turn off all power if the burner turns on with no water in the gauge glass.
Investigate further before continuing procedure.

!

CAUTION

If pump does not turn off or valve close, turn off water supply to boiler. Investigate
further before continuing procedure.

!

McDonnell & Miller

Xylem Inc.
8200 N. Austin Avenue
Morton Grove, Illinois 60053
Phone: (847) 966-3700
Fax: (847) 965-8379
www.mcdonnellmiller

McDonnell & Miller is a trademark of Xylem Inc. or one of its subsidiaries.
© 2013 Xylem Inc. MM-714C January 2013 Part No. 210422

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