Service Relay Requirement; Electrical Requirements - Watts AERCO EXT Installation, Operation & Maintenance Manual

Modulex EXT Commercial Series
CHAPTER 4: Installation Instructions
W A R N I N G !
DANGER OF FATAL ACCIDENT DUE TO ELECTRIC SHOCK! 120 VAC connections may be
present on the external connection board when power is supplied to the boiler.
The electrical connections must be carried out only by a qualified person. Before carrying out the
connections or any other operation on the electrical parts, always switch off and disconnect the
electricity supply and ensure for yourself that it cannot be accidentally turned on.

4.24.3 Service Relay Requirement

Upstream of the electrical connection, a service relay is required (not supplied) which, when the
additional electrical safety devices (if any) intervene, shuts down the electrical supply to the on-off fuel
valve fitted on the gas supply circuit, but NOT to the boiler, so as to guarantee the running of the pump
and permit the boiler to cool down.

4.24.4 Electrical Requirements

•
No changes may be made to the wiring of the boiler.
•
All connections should be designed in accordance with the applicable regulations.
•
Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and
dangerous operation.
NOTE: Verify proper operation of the boiler after all servicing operations.
Figure 4-17: 120VAC Power Wiring for Main Electrical Junction Box and Signal Wiring
W A R N I N G !
120 VAC cables shall be separated from 24VAC and signal wires, using the two plastic conduits
supplied within the boiler casing LEFT-HAND side panel.
OMM-0160_A • DRAFT
for Ufly Controller and Boiler Control Module (BCM)
Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST
Page 46 of 117