Weil-McLain WM97+100 Manual page 56

WM97+ Series 2
System piping
DHW as a zone — CIRCULATOR zoning
DO NOT use this piping if the boiler is connected to a Aqua
Logic (CWH) unit. The Aqua Logic (CWH) unit requires
priority and would prevent priority operation of the system
DHW unit.
The boiler internal primary/secondary by-pass valve MUST
be open to prevent excessive head caused by running the
boiler circulator and zone circulators in series.
1. the boiler internal primary/secondary by-pass valve.
2. 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.
3. Install the DHW tank as a system zone. The DHW tank can be piped
as a zone ONLY if a DHW tank or Aqua Logic (CWH) is
nected to the boiler.
4. Wire the DHW circulator to boiler Zone 1. Set the boiler circulator to
ON in the DHW Settings menu.
5. 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.
6. Terminate the bottom connections as shown in the inset on Figure 63.
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. The WM97+ control operates up to three zones (DHW plus two space
heating). Refer to Field wiring, beginning on page 67, for instructions
on wiring to circulators.
2. For more than three zones, use a Weil-McLain WMCR zone controller.
See suggested wiring in this manual.
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.
– 56 –
-
GAS FIRED WATER BOILER
(continued)
con-
Isolation valves.
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.
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.
as a zone
information — OPEN: Boiler
connected as primary/second-
ary.
Make-up water supply.
Backflow preventer, when
used.
Zone circulators.
Pressure reducing valve, when
used.
Quick-fill valve, when used.
DHW boiler water supply
connection, when used — see
page 14 for information.
Circulator zoning with DHW
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