Dpdt Transformer Relay (P/N 90436300) - Roberts Gorden Corayvac CRV-B Series Installation, Operation & Service Manual

temperature. The modulating controls offer many
features like 7 day programmability, four time periods
per day (2 occupied, 2 unoccupied), temporary
temperature setpoint override, keypad lockout
security and more.
Remote sensors or outdoor sensors are optional, not
required. Remote sensors will allow for zone
temperature averaging, if required.
12.3.1 Analog Signal Modulating Thermostat
A programmable, 7-day programming, modulating
thermostat can be installed to supply an analog (4-
20mA) or (2-10Vdc with 500 Ohm resistor) control
signal to dictate the speed of the pump. For
thermostat wiring, See Page 60, Figure 44. Optional
room sensors (P/N 10081520) and outdoor air
sensors (P/N 10081521) are available.
Room temperature averaging networks can be
Table 3: Modulating Thermostat Cable Requirements
Wire Function
Digital Outputs
Modulating Outputs
Outdoor Air Temperature Sensor 18 AWG (0.75 sq mm)
Remote Sensor
Power Wiring
LonWorks ® (P/N 90424104 only) 18 AWG
12.3.3 Sequence of Operation
Depending on the space temperature, the thermostat
will control the heat output based on demand signal
communicated from the thermostat program. The
thermostat will close contact on the transformer relay
(P/N 90436300). The VFD run command is
energized by the transformer relay. When the VFD
energizes the pump and the vacuum has been
established, the pressure switch will close and
energize the burners. At high heat, a demand signal
will turn the pump speed to a maximum frequency
and burner(s) ON at maximum firing rate. As the
space temperature gets closer to the set point, the
thermostat program will slow the pump speed and
burner(s) firing rate down until the room temperature
reaches the thermostat set point.
NOTE:
To obtain Analog 0-10VDC signal, connect as shown
on Page 69, Section 15.2 and set standard speed
source (parameter 05 inside VFD menu) to 03.
Recommended Wire Size
(Minimum)
18 AWG (0.75 sq mm)
18 AWG (0.75 sq mm)
18 to 22 AWG
(0.75 to 0.34 sq mm)
18 to 14 AWG
( 0.75to 2.0 sq mm)
(0.75 sq mm) nonshielded
created with up to nine room sensors (P/N
10081520). Refer to thermostat installation
instructions for wiring.
12.3.2 Cable Requirement
Table 3, on on Page 53 lists wiring types, sizes and
distances for modulating thermostat communication.
Power Requirement
Programmable thermostats requires 24 volt, AC
power.
Specification or
Requirement
Standard thermostat wire
1 pair
1 pair
Twisted pair wire
NEC Class II 140ºF (60°C )
1 pair

12.4 DPDT Transformer Relay (P/N 90436300)

The transformer relay wiring diagram is shown on
Page 56, Figure 39. The transformer relay can be
used to control an EP-100 or EP-201 pump
®
CORAYVAC system. The double pole relay can be
used to control one or two zones of burners. The
electrical circuit is a 120 V AC (20 A) supply. The
transformer 24 V AC output for the thermostat is
rated at 40 VA. Thermostats used with the
transformer must not exceed this power requirement.
A transformer relay operated system will not give any
post purge pump operation to completely exhaust
products of combustion from the system or provide
indication of operating conditions.
SECTION 12: C M
ONTROL
Distance (Maximum)
1000 ft (304 m)
500 ft (152 m)
500 ft (152 m)
1000 ft (304 m)
Limited by line-loss effects on power
consumption.
Refer to E-bus Wiring Guide 74-2865
for maximum length and generic cable
specifications.
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