Figure 72
ECO
low voltage
input and output connections
Part number 550-142-190/1218
63
Field wiring
(continued)
Low voltage wiring (24 VAC)
Make the following low-voltage connections, some of which
depend on your system and how the
ECO
control will be
programmed. The call outs below refer to Figure 72.
The control provides inputs for one DHW zone (priority)
and one heating zone.
P11
DHW input (DHW circuit only)
Only use the DHW input when the
system uses a DHW tank or other
Domestic Hot Water production device.
Do not use as a heating zone.
1. Control requires that DHW tanks be controlled from
DHW Input
if domestic water priority is required.
2. ALWAYS connect DHW aquastat or isolated relay
contacts from a DHW device to the DHW input.
Depending on system design, a zone control may be
necessary.
Unless system is exempt based on the
criteria listed on page 127, installer
must provide external controls that
distinguish between Aquastat (DHW)
and thermostat (HEAT) calls for heat if
external controls are needed.
P15
HEAT input (central heating)
1. Use
HEAT
input to:
a. Connect the thermostat for a space heating zone.
b. Connect end switch wire (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).
The
ECO
control will activate the 120VAC
HEAT Circ.
output if the
HEAT
thermostat or input device calls for heat,
after DHW heating is satisfied.
P10
Outdoor temperature sensor (for outdoor
reset)
1. The
ECO
control provides programmable options if
using an outdoor temperature sensor. This sensor is
supplied with the boiler.
The outdoor sensor must be
installed unless specifically exempted in the Energy
Act statement on page 127.
2. Mount the outdoor sensor on an exterior wall, shielded
from direct sunlight or flow of heat or cooling from other
sources. The wire outlet on the sensor must be oriented
DOWN to prevent water entry.
3. Connect the sensor leads to the black, 2-pin terminal
block, as shown in the wiring diagrams. Thermostat wire
can be used to connect the sensor.
P13
External limits (will cause manual reset when
opened)
- pins 1, 2
1. Connect isolated contacts of external limits in series
across pins 1 and 2 of the orange, 4-pin terminal block
to cause the
ECO
control to lock out (requiring manual
reset) if the limit opens. The limit must close and the
control must be re-started using the procedure given
in this manual.
P13
External limits (will cause automatic reset when
opened)
- pins 3, 4
1. Connect isolated contacts of external limits in series across
pins 3 and 4 of the orange, 4-pin terminal block to cause the
ECO
control to shut down the boiler on limit opening, then
automatically restart after the limit closes.
P12
Low water cut-off device (if used)
1. If using the optional kit, remove factory jumper from P12. Insert
4-pin molex connector from kit wire harness into P12.
2. To field wire a non-powered (isolated contact) low water cut-off,
clip the factory jumper in the factory installed molex plug, strip
the wires and connect to the LWCO’s isolated contacts
Thermostats
—
DO NOT
supply 24-volt power to
the thermostat circuits (P11 and P15 in Figure 72) or
attempt to supply 24 volts for any other application.
For thermostats that require a continuous 24-volt
power source, connect the thermostat power input
to “a separate 24V power source.”
Zone valves
— If using 3-wire zone valves, use relays
to provide dry contacts to the ECO control thermostat
connections. The zone valve end switches of 3-wire
valves carry 24VAC from the valve.
Thermostat anticipator setting
— 0.1 amps.
®
S
ERIES
2
G
AS
-
FIRED
WATER
BOILER
—
Boiler Manual
