Install Instructions

MINI-THERM JV
Page 19
5 I Low Water Cut Off (LWCO)
When this boiler is installed above radiation level,
it is required that a Low Water Cut-Off (LWCO) be
installed unless this requirement is superceded by
Jurisdictional requirements. Specic instructions for
the installation are the following:
Locate the appropriate wiring diagram within this
manual. There are two diagrams, one for the JVH
Series and one for the JVS Series. These boilers are
available for operation on 115/60 Hz or 220/50 Hz
power. If this boiler is to be operated at 220/50 HZ
use only a 24 VAC LWCO device. Depending upon
the Voltage requirements of the chosen LWCO device
(24 VAC or 120 VAC) wire the power wires for the
device in the following manner: For 120 VAC LWCO
devices, wire the power wires in parallel with the
incoming supply power to the boiler. For 24 VAC
LWCO devices, wire the power wires in parallel with
the 24 VAC output from the boiler’s transformer.
On the appropriate wiring diagram, locate the HI
LIMIT. Connect the switch contact wires from the
LWCO device in series with the blue wire (JVH) or
Orange wire (JVS) to the HI LIMIT. Follow LWCO
device Manufacturer’s Wiring Instructions for
identication of power wires and switch contact wires.
Mechanically, install the LWCO device in a tee tting
in the supply piping above the highest point of the
boiler. Follow LWCO Manufacturer’s Instructions for
minimum pipe sizing.
Perform a test of the Low Water Cut Off device
according to its Manufacturer’s Instructions before
leaving the boiler unattended.
Note: This boiler is a water tube boiler that requires
water ow through the heat exchanger for proper
operation. It does not have an operating water level
and must be full at all times. In accordance with ANSI/
ASME CSD-1 Section CW-210 and The National
Fuel Gas Code ANSI Z223.1/NFPA 54 Section 10.3.5
a water tube boiler shall have a water ow proving
device in lieu of a Low Water Cut Off.