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Figure 22 - Water Connections
Relief Valve
This unit is supplied with a relief valve(s) sized in accordance
with ASME Boiler and Pressure Vessel Code, Section IV
("Heating Boilers"). The relief valve(s) is installed in the
vertical position and mounted in the hot water outlet. Place no
other valve between the relief valve and the unit. To prevent
water damage, pipe the discharge from the relief valve to a
suitable floor drain for disposal when relief occurs. Do not
install any reducing couplings or other restrictions in the
discharge line. The discharge line will allow complete drainage
of the valve and line. Manually operate the relief valves at least
once a year.
CAUTION:
discharge water.
Water Flow Switch
A water flow switch is factory installed. The flow switch is
wired in series with the 24 VAC safety control circuit at the
units terminal strip. This wiring connection installs the flow
switch in the 24 VAC safety circuit to prove water flow before
main burner ignition. The factory supplied flow switch is
installed in the outlet side of the front header. These units
require a minimum flow of 26 GPM to make the flow switch
and start burner operation. Ensure that the pump installed on
the unit will supply adequate flow to make the flow switch
contacts and operate the unit. A water flow switch meets most
code requirements for a low water cut off device on appliances
requiring forced circulation for operation.
Avoid
contact
with
Installation and
Service Manual
Low Water Cutoff
(If Equipped)
If installing this unit above radiation level, you must install a
low water cut-off device at the time of appliance installation.
Electronic or float type low water cutoff controls are available
as a factory supplied option on all units. Inspect the low water
cutoff every six months, including flushing of float types. The
low water cutoff control is located on the control panel directly
behind the control panel cover.
The reset and test buttons (if equipped) are located on the
control panel.
CONNECTING TO
ELECTRICAL SUPPLY
This unit is wired for 120 VAC service. The unit, when
installed, must be electrically grounded in accordance with the
requirements of the authority having jurisdiction or in the
absence of such requirements, with the latest edition of the
National Electrical Code ANSI/NFPA No. 70. When the unit is
installed in Canada, it must conform to the CAE C22.1,
Canadian Electrical Code, Part 1 and/or local Electrical Codes.
1. Use only Type-T wire [63°F (35°C) rise] on all wiring
between the unit and field-installed devices.
2. Enclose line voltage wire exterior to the unit in approved
conduit or approved metal-clad cable.
3. The pump must run continuously when the unit is being
fired (hot water heating boilers must use the optional pump
delay if the pump is to be cycled. See Freeze Protection,
page 7 when cycling the pump). Water heaters use the
hot
pump delay as standard in accordance with ASHRAE 90.1
requirements.
4. To avoid serious damage, do not energize the unit until the
system is filled with water.
5. Provide the unit with proper overload protection.
21
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