Weil-McLain GV90+ - Manual (Page 12)

Part number 550-142-054/0411
GV90+
gas
-
fired water boiler
— Boiler Manual
12
Install water piping
Air separator
Install an air separator in the piping as shown in this
manual. For single-zone systems, install the air separator
in the return piping as shown in Figure 14, page 14. This
allows mounting the automatic air vent and expansion tank
off of the separator.
Install relief valve
1. Install relief valve ONLY as shown in Figure 12.
2. Connect discharge piping to safe disposal location, fol-
lowing guidelines in Figure 13, page 13.
Figure 12 Install and pipe relief valve
Legend
1 Jacket plug for unused relief valve jacket open-
ing.
2 Jackets are provided with two relief valve open-
ings because each jacket size is used for two boiler
sizes. Cover the unused opening with the plug
provided.
3 Boiler relief valve (from accessory bag)
4 ¾” x 3” nipple, provided in accessory bag
5 ¾” relief valve tapping in back section
6 Connect minimum ¾” discharge piping to relief
valve.
See Figure 13, page 13.
Use two wrenches when tightening water piping at
boiler , using one of the wrenches to prevent the boiler
interior piping from turning. Failure to support the boiler
piping connections to prevent them from turning could
cause damage to boiler components.
The cast iron heat exchanger return temperature must
be kept at or above 140°F during all times of operation
to prevent possibility of corrosion due to condensation.
This is done automatically, using the boiler's internal
circulators. DO NOT remove or tamper with these cir-
culators. Failure to comply could result in severe personal
injury, death or substantial property damage.
General piping information
Minimum pipe size for boiler loop piping
Figure 11 Provide boiler loop piping no smaller than listed
below (based on 20°F temperature rise)
Boiler loop pipe size, Minimum
GV90+3 or 4 1”
GV90+5 or 6 1¼”
Additional limit controls
Following standard industry practices, if installation is to comply with
ASME or Canadian requirements, an additional high temperature
limit may be needed. Consult local requirements for other codes/
standards to determine if needed. Wire as shown in Figure 67, page 56.
• Install a manual reset high temperature limit between the boiler
and the isolation valve.
• Wire the manual reset limit in series with the boiler limit con-
trol.
• Set the manual reset limit control at least 20°F above the boiler
limit control setting (maximum setting 220°F).
Low water cut-off, when required
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. Wire contact as shown in Figure 67, page 56.
If boiler is connected to heating coils located in air han-
dling units where they can be exposed to refrigerated
air, use flow control valves or other automatic means to
prevent gravity circulation during cooling cycle. Circu-
lation of cold water through the boiler could result in
damage to the heat exchanger, causing possible severe
personal injury, death or substantial property damage.
Backflow preventer
Where required by codes, install a backflow preventer in the cold
water fill line, as shown in suggested piping diagrams on following
pages. Install a check valve if a backflow preventer is not installed.