RTC DFC-X User manual

1
DOC# T0012 3.26.2019 DFC-X O&M
Ph. [phone]
www.RTC-Solutions.com
4370 Oakes Road, Suite 700
Fax [phone]
Email:in[email protected]
Davie, FL 33314
Model No. DFC-X Support 877-351-4702
DIRECT FIRED DIGITAL TEMPERATURE CONTROL INSTALLATION,
OPERATION, AND MAINTENANCE MANUAL
This manual covers the following products:
DFC-X
Direct fired control with integral 40-90°F (4-32°C) dial 0-24VDC output
TS-01
Temperature senor 40-250°F (4-121°C)
DFTD
Temperature dial 5 selectable ranges
RDU
Remote display unit
DAT-12
Discharge air tube
PWM-10V
PWM to 10V output converter
Table of Contents
Overview.....................................................................................................................................................................................................................................................2
Specifications..............................................................................................................................................................................................................................................2
Power Requirements..............................................................................................................................................................................................................................2
DFC-X Ambient Temperature Limits ..................................................................................................................................................................................................2
TS-01/DFTD Ambient Temperature Limits .......................................................................................................................................................................................2
Accuracy..................................................................................................................................................................................................................................................2
Installation ..................................................................................................................................................................................................................................................2
Wiring..........................................................................................................................................................................................................................................................2
Standard control with remote setpoint................................................................................................................................................................................................2
Standard control with integral setpoint ..............................................................................................................................................................................................3
Optional room space control ................................................................................................................................................................................................................4
Optional multiple setpoint temperature control ................................................................................................................................................................................5
Operation ....................................................................................................................................................................................................................................................5
Start up .................................................................................................................................................................................................................................................... 5
Sequence of operation............................................................................................................................................................................................................................5
Calibration ..............................................................................................................................................................................................................................................5
Troubleshooting .....................................................................................................................................................................................................................................5
LED Code Chart ....................................................................................................................................................................................................................................6
TS-01 and DFTD Resistance chart ........................................................................................................................................................................................................6

2
DOC# T0012 3.26.2019 DFC-X O&M
Ph. [phone]
www.RTC-Solutions.com
4370 Oakes Road, Suite 700
Fax [phone]
Email:in[email protected]
Davie, FL 33314
Overview
The Roof Top Control Solutions direct fired digital temperature control is a microprocessor based control that utilizes an intelligent PID software
algorithm to modulate gas flow to a burner in direct fired make up air applications. The closed loop system contains three components including the
temperature sensor (TS-01), the direct fired control (DFC-X), and the direct fired temperature dial (DFTD) or the remote display unit (RDU). The DFC-X
auto detects if there is a remote dial connected. When a remote is not connected, the DFC-X uses the internal setpoint. The system compares the
discharge temperature of the heating unit to the set point dial 40 times per second insuring accurate and repeatable temperature control. The software
provides smooth output control eliminating excessive swings observed with older analog systems. A 10 second start up delay is standard, and an
onboard LED indicates simple diagnostics.
Specifications
Power Requirements
DFC Ambient Temperature Limits
Storage
Operating
TS-01/DFTD Ambient Temperature Limits
Storage
Operating
Accuracy
24VAC 50/60Hz 20VA isolated class II
transformer
-40-140°F (-40-60°C)
-40-140°F (-40-60°C)
-40-250°F (-40-121°C)
-40-250°F (-40-121°C)
+/-3°F (1°C)
Installation
All control wiring should be shielded with the shielding grounded at one end only and/or the wiring should be
run in separate conduit from any high voltage wires. Interference from these sources could cause control function
errors or permanent damage. The DFC-X control should be mounted in a housing free from the elements of
weather. Insulated fork terminals are recommended for best contact when attaching wiring to the provided screw
terminals. The DFC-X can drive up to a .5 amp 24VDC direct acting solenoid.
The DFTD can be set to 5 different temperature ranges by moving jumper J1 as shown in Figure 1 on the back of
the dial to the desired position. 5 different temperature overlays are available to match the range chosen.
Wiring
Standard control with remote setpoint
Figure 2 –DFC-X wiring showing 24V DC output
Figure 1: DFTD Backside

3
DOC# T0012 3.26.2019 DFC-X O&M
Ph. [phone]
www.RTC-Solutions.com
4370 Oakes Road, Suite 700
Fax [phone]
Email:in[email protected]
Davie, FL 33314
PWM-10V
We do offer a PWM output converter to connect the DFC-X to a 0-10V actuator rather than a 24VDC solenoid valve. If you are utilizing the PWM-10V to
connect to a motorized actuator or any other device with it’s own power supply, than be sure the DFC-X has its own isolated transformer separate from
the power source for the actuator, or the control may be damaged.
Figure 3 –DFC-X wiring showing 0-10V DC output
Standard control with integral setpoint
The DFC-X, when using the onboard selector, should only be paired with RTC’s TS01(Temperature Sensor). Other resistive sensors can be used only
when paired with a compatible dial.

4
DOC# T0012 3.26.2019 DFC-X O&M
Ph. [phone]
www.RTC-Solutions.com
4370 Oakes Road, Suite 700
Fax [phone]
Email:in[email protected]
Davie, FL 33314
Figure 4 –DFC-X wiring showing 24V DC output
Optional room space control
Figure 5 - Room space control with thermostat
A standard make or break thermostat with normally open contacts can be connected between terminals 1 and 2 as shown in Figure 5. When connected
in this way the thermostat may be set for a desired room temperature for space control applications. When the room thermostat is satisfied, the
discharge temperature will return to the temperature set on the dial on the front of the DFTD. With older models of the DFTD, there is a
potentiometer(R1) on the back of the control that controls how much the temperature will increase by when the room thermostat calls for more heat. For
proportional room space control, the DFC-X may be connected as shown in Figure 6. See RDU literature for details.
Figure 6 - Room space control with digital space control

5
DOC# T0012 3.26.2019 DFC-X O&M
Ph. [phone]
www.RTC-Solutions.com
4370 Oakes Road, Suite 700
Fax [phone]
Email:in[email protected]
Davie, FL 33314
Optional multiple setpoint temperature control
Figure 7 - Control with multiple set points
More than one temperature dial can be connected as shown in Figure 7 for applications such as paint spray booths or process control.
Operation
Start up
Setting low fire –The minimum firing rate may be set by removing the wire from the terminal number 6 on the DFC-X control. This disconnects the
power to the control valve. Refer to the control valve manufacturer’s literature for this adjustment. You can also set low fire by entering Maintenance
Mode as described below.
Setting high fire –The maximum firing rate may be set by removing the wire from terminal number 4 on the DFC-X control. This disconnects the
discharge air sensor and sets the output to the control valve to its maximum. While setting high fire, the LED will repeatedly blink red. Refer to the
control valve manufacturer’s literature for this adjustment. You can also set high fire by entering Maintenance Mode as described below.
Sequence of operation
Upon applying power to the DFC-X control the 10 second start up delay will begin indicated by a slow blinking green LED (about once every 2 seconds)
on the face of the control. After the start up delay has completed, the LED will either repeatedly blink green twice or repeatedly blink green three times
depending on whether you are using an external setpoint or the internal setpoint. When using the internal setpoint the control will repeatedly blink
twice and when connected to an external setpoint it will repeatedly blink three times. At this time the control will begin modulating the output as
required. Any system errors are indicated by various LED codes described in Figure 8 below.
Maintenance Mode
To enter maintenance mode short terminals 1 with 2 as well as 3 with 4. The LED will blink red and green repeatedly to indicate it is in maintenance
mode. In this mode you can turn the knob on the front of the control to directly operate the valve. When turned all the way clockwise the valve would
be fully open. Conversely, when turned all the way counter clockwise the valve would be closed. This mode can be used to set low fire and high fire.
To set low fire, turn the knob counter clockwise and refer to the control valve manufacturer’s literature for this adjustment. To set high fire, turn the
knob clockwise and refer to the control valve manufacturer’s literature for this adjustment.
Troubleshooting
The DFC-X control provides some diagnostics via the on board LED labeled “STATUS”. A system fault is indicated by various LED codes described in
Figure 8. They usually indicate that the sensor or dial are either disconnected or improperly wired. Check all connections per the included wiring
diagrams. The fault also may be caused by a damaged sensor or dial. Both devices may be tested with an Ohmmeter by removing the wires from the

6
DOC# T0012 3.26.2019 DFC-X O&M
Ph. [phone]
www.RTC-Solutions.com
4370 Oakes Road, Suite 700
Fax [phone]
Email:in[email protected]
Davie, FL 33314
DFC control and measuring across the device. The devices should measure between 12.8K and 7K OHMS. If there is a fault light and the devices
measure the proper resistance then the control may be damaged. If there is no fault light but the system is not modulating properly you may check the
control output by repeating the start up procedure and measuring terminals 5 and 6 on the DFC-X as stated below.
Figure 8 –LED Code Chart
Measuring the Control Output
Remove the wire from terminal number 4 on the DFC control and measure the voltage across terminals 5 and 6 with a voltmeter. The meter should read
from 20 to 24 Volts. If it does not, disconnect the wires from the valve and measure the output without the valve connected. If it reads 20 to 24 Volts,
refer to the valve manufactures literature for troubleshooting the valve. If it does not the control may be damaged.
DFTS and DFTD Resistance chart
Sensor
Resistance
Dial Resistance
Temp °F
Temp °C
40-250
40-90
80-130
120-170
160-210
200-250
40
4.4
11210
11250
50
10.0
11020
11050
60
15.6
10826
10850
70
21.1
10630
10650
80
26.7
10433
10450
10380
90
32.2
10234
10250
10180
100
37.8
10034
9980
110
43.3
9830
9780
120
48.9
9624
9580
9590
130
54.4
9413
9380
9390
140
60.0
9199
9190
150
65.6
8983
8990
160
71.1
8766
8790
8700
170
76.7
8550
8590
8500
180
82.2
8337
8300
190
87.8
8130
8100
200
93.3
7930
7900
8060
210
98.9
7740
7700
7860
220
104.4
7560
7660
230
110.0
7393
7460
240
115.6
7237
7260
250
121.1
7095
7060