TC 204 Heating Controller
The TC204 is a multi-purpose heating controller with built-in programs for different types of heating systems.
General Data
Power requirement
24 volts ac, 25 va
Inputs
3 10k ohm ntc thermistors
1
digital
Outputs
3
digital
2 analog 0 - 10 volt dc
This manual covers outdoor reset of hot water heating systems using a mixing valve and a 3-point
floating actuator. For other applications see the expanded manual at www.paxtoncorp.com
Wiring
The diagrams show ESBE #62E (Paxton VM62) & 92-2M (Paxton VM92) valve actuators . These are 3-wire
floating, 24 volt ac valve motors which fit ESBE 3-way & 4-way valves.
VM62 actuators are used with valve sizes 1/2” through 2”: VM 92 actuators are used with valve sizes 2 1/2” - 6”.
Actuators of this type have a common wire. Voltage applied between the common and one of the remaining wires
drives the valve open and voltage between the common the the remaining wire drives the valve closed. If no volt-
age is applied to either terminal the valve stays in place.
Other valves with different floating actuators may be used provided the voltage is 24 volts and the current draw
of the actuator does not exceed the capacity of the TC204 (25 VA). If these 2 conditions are not met the actuator
must be operated through intermediate relays.
Programs
There are eight programs in the TC204. This manual is for Program No.1 which is the default program.
Some not frequently used functions are not covered in this manual. Instructions for these as well as for all other
programs are available at:
www.paxtoncorp.com
Other programs provide outdoor reset by modulating valves that accept a 0 - 10 volt dc signal, outdoor reset by
direct boiler control, zone control without outdoor reset, and outdoor control of steam heating systems.
Program No. 1
Program 1 is
Supply Water Temperature Control using a 3-point floating valve actuator. The control mode can be
Outdoor Reset
with or without a room sensor, or direct control by room temperature only.
The supply temperature sensor must always be installed.
Outdoor reset is automatically initiated if the outdoor temperature sensor is installed.
Room temperature control is automatically initiated if the room temperature sensor is installed.
Additional functions are
Pump Control
,
Auxiliary Output
, and
Return Water Low Limit (see page 8)
.
Temperature Sensors
The supply water and outdoor air temperature sensors are included with the TC204. A room temperature sensor
is optional. A room sensor is also built into the TC204, but to use it the TC204 must be installed in the controlled
space.
1
Notes to the installer:
1. Program #1 - Outdoor reset control using a mixing valve, is the default program.
2. All defaults in program #1 will work in most cases.
3. Connect all sensors, the actuator wires and power supply. Set time & date (page 9)
and let the system stabilize, before making any program changes.
Nothing else needs to be done in most cases.
ver. 1.32-01
