13
Part Number 550-142-785/0812
Table 6
Water pipe size (based on 20 °F rise)
General
Boiler
model
number
To
system
From
system
GWI-047
¾”
¾”
GWI-063
1”
1”
GWI-095
1”
1”
GWI-127
1”
1”
GWI-158
1 ¼”
1 ¼”
GWI-190
1 ¼”
1 ¼”
GWI
Series 2
Gas-Fired Water Boilers –
Boiler Manual
If installation is to comply with ASME or Canadian requirements,
an additional high temperature limit is needed. Install control in
supply piping between boiler and isolation valve. Set second
control to minimum 20 °F above setpoint of first control. Maximum
allowable setpoint is 240 °F. See
page 24 and 25
for wiring.
A low water cutoff device is required when boiler is installed above
radiation level or by certain state or local codes or insurance
companies. Use low water cutoff designed for water installations.
Electrode probe-type is recommended. Purchase and install in
tee in supply piping above boiler.
Use backflow check valve in cold water supply if required by
local codes.
See Figure 9
(diaphragm-type or bladder-type expansion tank)
or Figure 10 (closed-type expansion tank) on
page 14, and Table
6
, for near-boiler and single-zone systems designed for return
water at least 130 °F.
See page 13
for multiple-zone piping.
See page 14
for boilers used with refrigeration systems.
Near-boiler piping
Relief valve
Install relief valve vertically in ¾” tapping on side of boiler. See
the tag attached to the relief valve for manufacturer’s instructions.
To avoid water damage or scalding due to valve
operation, discharge line must be connected to re-
lief valve outlet and run to a safe place of disposal.
Terminate the discharge line to eliminate possibility
of severe burns should the valve discharge.
• Discharge line must be as short as possible and be
the same size as the valve discharge connection
throughout its entire length.
• Discharge line must pitch downward from the valve
and terminate at least 6” above the floor drain where
any discharge will be clearly visible.
• The discharge line shall terminate plain, not thread
-
ed, with a material serviceable for temperatures of
375 °F or greater.
• Do not pipe the discharge to any place where freez
-
ing could occur.
• No shutoff valve shall be installed between the relief
valve and boiler, or in the discharge line. Do not plug
or place any obstruction in the discharge line.
• Failure to comply with the above guidelines could
result in failure of the relief valve to operate, result
-
ing in possibility of severe personal injury, death or
substantial property damage.
• Test the operation of the valve after filling and pres
-
surizing system by lifting the lever. Make sure the
valve discharges freely. If the valve fails to operate
correctly, replace it with a new relief valve.
Circulator
The circulator is shipped loose (wiring pre-attached to boiler)
to allow you to locate it either in the return or supply piping, as
desired. See page 14
for a typical installation. Pipe the expansion
tank to the suction side of the circulator whenever possible. Install
an air separator in the supply piping. Connect the expansion tank
to the air separator only if the separator is on the suction side of
the circulator. Always install the system fill connection at the same
point as the expansion tank connection to the system.
Figures 4
and 5 show typical near-boiler piping connections.
Expansion tank
Diaphragm- or bladder-type expansion tank — Figure 9,
page 14
1. Ensure expansion tank size will handle boiler and system
water volume and temperature. Tank must be located in boiler
return piping as close to boiler as possible, before inlet side
of circulator. See tank manufacturer’s instructions for details.
2. Install an automatic air vent as shown.
Closed-type expansion tank — Figure 10, page 14
1. Ensure expansion tank size will handle boiler and system water
volume and temperature. See tank manufacturer’s instructions
for details.
2. Connect tank to ½” NPT tapping located behind supply outlet,
using ½” NPT piping. Pitch any horizontal piping up towards
tank 1 inch per 5 feet of piping.
Undersized expansion tanks cause system water
to be lost from relief valve and makeup water to be
added through fill valve. Eventual section failure can
result.
Water piping — multiple zone systems
Install system piping using either circulator zoning or zone valve
zoning. Install expansion tank on suction side of system pump.
Always connect fill line only at the expansion tank — never at
another point in the system.
DO NOT connect directly from 3-wire zone
valves to the T-T terminals on the boiler
.
When using 3-wire zone valves, install an isolation
relay. Connect the zone valve end switch wires to
the isolation relay coil. Connect the isolation relay
contact across the boiler T-T terminals. Failure to
comply can result in damage to boiler components
or cause unreliable operation, resulting in severe
property damage.
4 Install water piping
4 Install water piping
