Weil-McLain WM97+100 Manual page 50

WM97+ Series 2
System piping
ZONE VALVE zoning — primary/secondary
The boiler primary/secondary by-pass valve
for single-boiler WM97+155 applications, with system con-
nected as primary/secondary.
the boiler internal primary/secondary by-pass valve.
1.
2. Install a system circulator (supplied by installer) as shown.
3. A benefit of primary/secondary piping is that it does not apply the head
of the boiler circulator to the system zone valves.
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 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 connected as a zone if a DHW
tank or Aqua Logic (CWH) is
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 57.
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+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.
– 50 –
-
GAS FIRED WATER BOILER
(continued)
connected to the boiler.
To provide
System circulator.
System expansion tank, dia-
phragm type, when 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 44 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, when
used.
Pressure reducing valve, when
used.
Quick-fill valve, when used.
DHW boiler water supply
Zone valve zoning —
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