Detroit Radiant Products Company LD3 Series - Manual (Page 41)

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LD3 Series 3.0 Installation • Thermostat Connection
The thermostat terminal designations are as follows:
R: 24VAC Power
W1: Call for Heat - Low Fire
W2: Call for Heat - High Fire
C: Common for 24VAC Power (if required for thermostat power)
24VAC is supplied from an internal 40VA transformer. DO NOT supply 24 Volts to the terminal strip.
Figure 3.27 • Single Two-Stage Heater, Single Thermostat Connection
Controlling Multiple Heaters with a Single Control Device
When multiple heaters are operated by the same control device (for example, common vented heaters),
an external relay kit (Part #ERK) must be utilized per heater. This allows the heater’s 24V supply voltage to
be isolated from the external control voltage of the thermostats. The ERK is to be installed on or near the
heater. Follow the instructions that accompany the accessory for more information and wiring diagrams.
Figure 3.28 • Multiple Heaters, Single Thermostat Connection with External Relay Kit
Thermostat Location
The location of the thermostat should be determined by the desired heating requirements and be
mounted on an inside wall five (5) feet above the finished floor. Locate the thermostat in a conspicuous
location, away from where it could be influenced by heat from the unit or other sources, as this may
cause the unit to short cycle. Care should be given to locate the thermostat away from drafts or
frequently opened doors. To prevent drafts inside the wall from affecting the thermostat’s performance,
plug hole for the wire with insulation or suitable caulk. For further information, see the accompanying
instructions with the thermostat.
C
R
W1
W2
Two-Stage
Thermostat
OPTIONAL 24V COMMON
CHECK THERMOSTAT
INSTRUCTIONS TO SEE
IF NEEDED.
RELAY BOX
(1 PER HEATER)
W2
W1
R
C
TRANSFORMER
L1
L2
P/N: ERK
C W1 W2
RELAY BOX
(1 PER HEATER)
P/N: ERK
C W1 W2
RELAY BOX
(1 PER HEATER)
P/N: ERK
C W1 W2
NOTE: W2 NOT USED ON SINGLE STAGE SCENARIOS
HEATER
TERMINAL
HEATER
TERMINAL
HEATER
TERMINAL THERMOSTAT
OPTIONAL 24V COMMON
CHECK THERMOSTAT
INSTRUCTIONS TO SEE
IF NEEDED
24V 120V