Install Water Piping - Weil-McLain WM97+ Manual

WM97+ -
gas fired water boiler

Install water piping

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.
General piping information
Additional controls, when required
The control module uses temperature sensors to provide
both high limit protection and modulating temperature
control. Some codes/jurisdictions may require additional
external controls for high limit and/or low water cutoff
protection.
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.
1. Install a manual reset high temperature limit constructed to pre-
vent a temperature setting above 200°F in system supply piping
between boiler and isolation valve. (Note that the control module
operating limit function shuts the boiler down at 195°F, or lower
if set to a lower value.)
Multi-temperature systems
includes circuits that require lower temperature water
(radiant slab circuits, for example) as well as higher
temperature circuits, it is recommended to protect low-
temperature circuits with limit controls that are wired
to a control module external limit circuit terminals.
2. See instructions beginning on page 45 for wiring information.
3. If using a manual reset limit control or wiring in the manual reset
circuit, set control module boiler limit at least 20°F less than the
external manual reset limit (i.e., set control module no higher than
180°F for a 200°F external limit, for example).
Backflow preventer
1. Use backflow preventer in the cold water supply piping when
required by local codes.
Internal expansion tank
1. The boiler is equipped with an internal expansion tank, factory
charged to 12 PSIG.
2. This expansion tank is suitable for most systems with total volume
of 15 gallons or less. See page 35 for suggestions for adding addi-
tional a supplementary expansion tank for higher-volume systems.
3. The maximum operating pressure of the internal expansion tank
is 42.5 PSIG.
The internal expansion tank isolation valve must be
turned off during hydrostatic testing.
The internal expansion tank
ALL TIMES OF OPERATION.
Part number 550-142-058/0811
— Boiler Manual
— If the heating system
MUST BE OPEN DURING
Install relief valve
1. Install relief valve in ¾" street elbow piped from boiler
supply piping tee (Figure 6, page 10).
2. Pipe the relief valve only as shown, in the location
shown.
3. Connect discharge piping to safe disposal location, fol-
WARNING
lowing guidelines in the
To avoid water damage or scalding
due to relief valve operation, as per
local or state codes
Discharge line must be connected to relief
valve outlet and run to a safe place of
disposal. Terminate the discharge line in
a manner that will prevent possibility of
severe burns or property damage should
the valve discharge. Locate away from the
top of the boiler.
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 threaded, with a material serviceable
for temperatures of 375 °F or greater.
Do not pipe the discharge to any place
where freezing could occur.
No shutoff valve shall be installed be-
tween the relief valve and boiler, or in the
discharge line. Do not plug or place any
obstruction in the discharge line.
Test the operation of the valve after fill-
ing and pressurizing system by lifting
the lever. Make sure the valve discharges
freely. If the valve fails to operate cor-
rectly, replace it with a new relief valve.
Failure to comply with the above guide-
lines could result in failure of the relief
valve to operate, resulting in possibility
of severe personal injury, death or sub-
stantial property damage.
below.
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33