Weil-McLain WM97+100 Manual page 49

WM97+ Series 2
System piping
ZONE VALVE zoning — primary/secondary
The boiler primary/secondary by-pass valve
to prevent excessive head caused by running the boiler circula-
tor and system circulator in series.
1. This configuration is for WM97+70 or 110 zone valve systems that need
more flow than the boiler's circulator can provide (see page 48 for infor-
mation).
the boiler internal primary/secondary by-pass valve.
2.
3. Install a system circulator (supplied by installer) as shown.
4. A benefit of primary/secondary piping is that it does not apply the head of
the boiler circulator to the system zone valves.
1. Connect the supplementary expansion tank and make-up water piping as
shown in Figure 50, page 45.
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 Aqua
Logic (CWH) manual for Aqua Logic (CWH) piping instructions.
2. DHW as a zone — A DHW tank can be piped as a zone if a DHW tank
or Aqua Logic (CWH) is
priority operation in this case, a Weil-McLain WMZV must be used.
3. Priority option — By default, the WM97+ control turns off space heating
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 56.
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 wiring,
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+70 or 110 boiler :
Indirect water heater, if 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.
Part number 550-142-204/0117
-
GAS FIRED WATER BOILER
(continued)
connected to the boiler. To provide DHW
System circulator.
Supplementary expansion
tank, diaphragm type, if used.
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 43 for
— Boiler Manual
DHW refers to an indirect-fired domestic hot
water storage tank. CWH refers to a Weil-
McLain Aqua Logic Water Heater.
primary/secondary connection —
a system circulator is required
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.
information — OPEN: Boiler
connected as primary/sec-
ondary.
Make-up water supply.
By-pass pressure regulator,
RECOMMENDED for zone
valve systems unless other
provision is made.
Backflow preventer, if used.
Pressure reducing valve, if
used.
Internal expansion tank,
diaphragm-type.
Quick-fill valve, if used.
Zone valve zoning —
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.
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