Weil-McLain WM97+100 Manual page 58

WM97+ Series 2
System piping
WATER CHILLER systems — ZONE VALVES
1.
the boiler internal primary/secondary by-pass valve.
2. The chiller must be piped in parallel with the boiler.
3. Use appropriate valves to prevent chilled medium from entering boiler.
4. Circulator zoning option — The space heating system can be zoned with
circulators if a separate circulator is supplied for the chilled water loop.
Install a separate circulator for each zone. The boiler circulator
be used for a zone. It must remain in the boiler, as installed at the factory.
If antifreeze is used in the system, consider the effects of antifreeze
on circulator sizing and DHW performance. Some local codes
may require double-wall DHW heat exchanger design. Use only
the antifreeze listed by Weil-McLain for use with this boiler. See
page 91 for details.
Chilled medium, if used, is piped in parallel with heating boiler
as shown in Figure 64. Use appropriate valves to prevent chilled
medium from entering boiler. If boiler is connected to heating
coils located in air handling units where they can be exposed
to refrigerated air, use flow control valves or other automatic
means to prevent gravity circulation during cooling cycle.
1. Provide a system expansion tank following the guidelines on page 46.
2. DO NOT use a closed-type tank if connecting to a water heater that is
equipped with an automatic air vent.
1. DHW or Aqua Logic (CWH) direct connection — Pipe from the boiler's
bottom connections to water heater boiler connections as shown. See the
Aqua Logic (CWH) manual for Aqua Logic (CWH) piping instructions.
2. DHW tank as a zone — A DHW tank can be piped as a zone (as in
Figure 63, page 56) if a DHW tank or Aqua Logic (CWH) is
nected to the boiler. To provide DHW priority operation in this case, a
Weil-McLain WMZV must be used.
3. Priority option — By default, the WM97+ control turns off space heat-
ing to its Zone 2 and Zone 3 outputs during domestic water heating on
Zone 1. The MAX ON TIME setting can be adjusted to limit how long
this occurs. Set the MAX ON TIME to "0" to disable domestic priority.
4. If connecting a water heater, terminate the bottom connections as
shown in the inset on Figure 65.
1. The WM97+ control can be set up to operate on space heating only or
on space heating plus DHW or Aqua Logic (CWH). Refer to Field wir-
ing, beginning on page 67, for instructions on wiring to zone valves.
2. The boiler and zone valves can also be operated by a Weil-McLain
WMZV zone controller.
WM97+155 boiler :
Indirect water heater, when
used (for Aqua Logic (CWH)
installations, refer to the
Weil-McLain Aqua Logic
(CWH) manual).
Relief valve, supplied with
boiler, field piped — MUST
be piped to boiler supply
connection — see page 14 for
information.
Relief valve piping to drain —
see page 42.
DHW circulator.
Isolation valves.
System circulator.
– 58 –
-
GAS FIRED WATER BOILER
(continued)
con-
Air separator.
Flow/check valves.
Purge/drain valves (one drain
valve is supplied loose with
the boiler).
Boiler circulator, with inte-
gral flow/check valve, factory
installed in boiler.
Zone valves.
Primary/secondary by-
pass valve — see page 44 for
information — OPEN: Boiler
connected as primary/second-
ary.
System expansion tank, closed
type, when used (some chiller
— Boiler Manual
DHW refers to an indirect-fired domestic
hot water storage tank. CWH refers to a
Weil-McLain Aqua Logic Water Heater.
optional DHW piping
Connect zone valve end switches to ZONE 2 input.
Connect system circulator to CIRC 2 output.
Use isolation relays if connected 3-wire zone valve end
switches to the WM97+ control inputs.
systems may use a diaphragm
type expansion tank).
Water chiller.
Check valve.
Y-strainer.
Balancing valve.
Make-up water supply.
By-pass pressure regulator,
RECOMMENDED for zone
valve systems unless other
provision is made.
Backflow preventer, when
used.
Pressure reducing valve, when
used.
Quick-fill valve, when used.
Chilled water system plus
DHW boiler water supply
connection, when used — see
page 14 for information.
DHW boiler water return
connection, when used — see
page 14 for information.
Pressure/temperature
gauge, supplied with boiler,
field piped.
Heating circuits.
Additional heating circuits, if
any.
= Items supplied with boiler
— all other items supplied by
installer.
Part number 550-142-204/0117