Weil-McLain WM97+ Aqua Logic, Manual

Page: 47 / 108

Part number 550-142-058/0811
47
WM97+
gas
-
fired water boiler
— Boiler Manual
Figure 52 WM97+ low voltage input and output
connections (24 VAC)
Thermostats
—
DO NOT
supply 24-volt
power to the thermostat circuits (H, J and
K in Figure 52) or attempt to supply 24 volts
for any other application.
For thermostats that require a continuous
24-volt power source, connect the ther-
mostat power input to the “R-C 24 VAC”
terminal of the lower voltage terminal strip.
Zone valves — If using 3-wire zone valves,
use relays to provide dry contacts to the
WM97+ control module thermostat con-
nections. The zone valve end switches of
3-wire valves carry 24 VAC from the valve.
Thermostat anticipator setting
— 0.1
amps.
Control module factory default settings:
DHW heating is configured for direct pip-
ing to the bottom of the boiler. The DHW
circulator is powered from Zone 1 on a
call from the DHW aquastat (connected to
Zone 1 input). With this set-up, the boiler
circulator is NOT activated during DHW
heating. Zone 2 and Zone 3 are also NOT
activated during domestic priority heating
on Zone 1.
The factory default for space heating is de-
signed for finned-tube baseboard, and set
up to activate Zone 2 and Zone 3 on a call
for heat from the zone thermostats.
See instructions on the following pages to
adjust the control module settings to match
installation requirements.
Field wiring
(continued)
Low voltage wiring (24 VAC)
Make the following low-voltage connections, some of which depend on
your system and how the WM97+ control module will be programmed.
The callouts below refer to Figure 52.
H
Zone 1 call for heat (space heating or DHW circuit)
1. The control module provides inputs for up to three zones.
The control module default setting is for three space
heating zones. The control settings must be changed to
operate on DHW. When operating on space heating only,
the Zone 1 output can be used as described for Zone 2.
2. Control options require that DHW tanks be controlled from Zone 1
if domestic water priority is required.
3. ALWAYS connect DHW aquastat to Zone 1 input if domestic pri-
ority is required. This can be done when the DHW tank is piped
to the DHW connections out the bottom of the WM97+ or when
the DHW tank is piped as a separate zone in the system.
4. Zone valve applications — see WARNING at right.
J
Zone 2 call for heat (space heating)
1. Use the Zone 2 input to:
a. Connect the thermostat for a space heating zone.
b. Connect end switch wire(s) (must be ISOLATED contacts) to
start boiler on a call for space heating.
c. Connect system control input for space heating call for heat
(ISOLATED contact only).
2. The WM97+ control module will activate the 120-VAC Zone 2
output if the Zone 2 thermostat or input device calls for heat, after
DHW heating is satisfied.
K
Zone 3 call for heat (space heating)
1. Same as Zone 2.
M
Outdoor temperature sensor (for outdoor reset)
1. The control module provides programmable options when using
an outdoor temperature sensor. This sensor is supplied with the
boiler. RECOMMENDED: For highest boiler/system efficiency,
install the outdoor sensor and set the control module for outdoor
reset operation.
2. Mount the outdoor sensor on an exterior wall, shielded from direct
sunlight or flow of heat or cooling from other sources. The wire out-
let on the sensor must be oriented DOWN to prevent water entry.
3. Connect the sensor leads to the ODT TEMP terminals, as shown
in the wiring diagrams. Thermostat wire can be used to connect
the sensor. EXCEPTION: Use shielded wire if running more than
10 feet or when running close to other wiring.
N
External limits (will cause manual reset when opened)
1. Connect isolated contacts of external limits across the MAN LIMIT
terminals to cause the control module to lock out (requiring
manual reset) when the limit opens. The limit must close and the
control must be re-started using the procedure given in this manual.
P
External limits (will cause automatic reset when opened)
1. Connect isolated contacts of external limits across the AUTO LIM-
IT terminals to cause the control module to shut down the boiler
on limit opening, then automatically restart after the limit closes.
R
Alarm terminals
1. The alarm contacts will close when the control module enters lock-
out. Contacts will remain closed until the control module is reset.
2. Alarm contacts are isolated and are rated 1 amp at 24 VAC.