RTC DFC Series User manual

DFC-1 STANDARD TEMPERATURE CONTROL
RDU
DFC+
DAT
DFTS
Ph. 877.351.4702
Fax [phone]
www.RTC-Solutions.com
4380 Oakes Road, Suite 804
Davie, Florida 33314
24 Volt AC input
Built in 15 second low fire start timer
0-24 Volt DC modulating output
Remote temperature selection
Calibration trim pot
Fits ¼” wiring terminals
Mounting footprint matches other industry standard controls
Rated for -40°F (-40°C)
DFC-2 TEMPERATURE CONTROL w/ INTEGRAL 40°F-90°F SELECTOR
DFTD TEMPERATURE SELECTION DIAL
DFTS TEMPERATURE SENSOR
DAT DISCHARGE AIR TUBE
24 Volt AC input
Built in 15 second low fire start timer
0-24 Volt DC modulating output
Integral temperature selection
Calibration trim pot
Fits ¼” wiring terminals
Mounting footprint matches other industry standard controls
Rated for -40°F (-40°C)
5 Selectable temperature ranges with one dial
40°F-90°F (4°C-32°C)
80°F-130°F (26°C-54°C)
120°F-170°F (48°C-26°C)
160°F-210°F (71°C-99°C)
200°F-250°F (93°C-121°C)
Combine dials for dual temperature selection
Fits ¼” wiring terminals
Mounting footprint matches other industry standard controls
40°F-250°F (4°C-121°C) temperature range
Fits ¼” wiring terminals
Mounting footprint matches other industry standard controls
Galvanized construction
Mounting footprint matches other industry standard controls

1
DOC# T0001 8.11.2014 DFC-X O&M
Ph. [phone]
www.RTC-Solutions.com
4380 Oakes Road, Suite 804
Fax [phone]
Email:[e-mail]
Davie, FL 33314
Model No. DFC-X
DIRECT FIRED DIGITAL TEMPERATURE CONTROL INSTALLATION,
OPERATION, AND MAINTENANCE MANUAL
This manual covers the following products:
DFC-1
Standard direct fired temperature control 0-24VDC output
DFC-2
Direct fired control with integral 40-90°F (4-32°C) dial 0-24VDC output
DFTS
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 Ambient Temperature Limits ......................................................................................................................................................................................................2
DFTS/DFTD Ambient Temperature Limits .......................................................................................................................................................................................2
Accuracy..................................................................................................................................................................................................................................................2
Installation ..................................................................................................................................................................................................................................................2
Wiring..........................................................................................................................................................................................................................................................2
Standard control with remote setpoint................................................................................................................................................................................................2
Standard control with integral setpoint ..............................................................................................................................................................................................4
Optional room space control ................................................................................................................................................................................................................4
Optional multiple setpoint temperature control ................................................................................................................................................................................5
Operation ....................................................................................................................................................................................................................................................6
Start up .................................................................................................................................................................................................................................................... 6
Sequence of operation............................................................................................................................................................................................................................6
Calibration ..............................................................................................................................................................................................................................................6
Troubleshooting .....................................................................................................................................................................................................................................6
DFTS and DFTD Resistance chart ........................................................................................................................................................................................................6

2
DOC# T0001 8.11.2014 DFC-X O&M
Ph. [phone]
www.RTC-Solutions.com
4380 Oakes Road, Suite 804
Fax [phone]
Email:[e-mail]
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
direct fired temperature sensor (DFTS), the direct fired control (DFC), and the direct fired temperature dial (DFTD). 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
DFTS/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 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 control should be mounted in a housing free from the elements of weather. Insulated fork terminal
terminations are recommended for best contact when attaching wiring to the provided screw terminals. Models DFC-1
and DFC-2 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.
** Important! When using the PWM-10V output converter to connect the DFC to a motorized actuator, or any other
device with its own power supply, the DFC must have its own isolated transformer separate from the power source
for the actuator, or the control may be damaged.
Wiring
Standard control with remote setpoint
Figure 2 – DFC-1 wiring showing 24V DC output
Figure 1: DFTD Backside

3
DOC# T0001 8.11.2014 DFC-X O&M
Ph. [phone]
www.RTC-Solutions.com
4380 Oakes Road, Suite 804
Fax [phone]
Email:[e-mail]
Davie, FL 33314
Figure 3 – DFC-1 wiring showing 0-10V DC output

4
DOC# T0001 8.11.2014 DFC-X O&M
Ph. [phone]
www.RTC-Solutions.com
4380 Oakes Road, Suite 804
Fax [phone]
Email:[e-mail]
Davie, FL 33314
Standard control with integral setpoint
Figure 4 – DFC-2 wiring showing 24V DC output
Optional room space control
Figure 5 - Room space control with thermostat

5
DOC# T0001 8.11.2014 DFC-X O&M
Ph. [phone]
www.RTC-Solutions.com
4380 Oakes Road, Suite 804
Fax [phone]
Email:[e-mail]
Davie, FL 33314
Figure 6 - Room space control with digital space control
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. Potentiometer R1 on the back of the DFTD sets how
much the temperature will increase by when the room thermostat calls for more heat. When the room thermostat is satisfied, the discharge temperature
will return to the temperature set on the dial on the front of the DFTD. For proportional room space control, the DFC-1 may be connected as shown in
Figure 6. See RDU literature for details.
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.

6
DOC# T0001 8.11.2014 DFC-X O&M
Ph. [phone]
www.RTC-Solutions.com
4380 Oakes Road, Suite 804
Fax [phone]
Email:[e-mail]
Davie, FL 33314
Operation
Start up
Setting low fire - The minimum firing rate may be set by removing the wire from terminal number 6 on the DFC control. This disconnects the power to
the control valve. Refer to the control valve manufactures literature for this adjustment.
Setting high fire – The maximum firing rate may be set by removing the wire from terminal number 4 on the DFC control. This disconnects the
discharge air sensor and sets the output to the control valve to its maximum. Refer to the control valve manufactures literature for this adjustment.
Sequence of operation
Upon applying power to the DFC control the 10 second start up delay will begin indicated by a slow blinking LED (about once every 2 seconds) on the
face of the control. After the start up delay has completed, the LED will turn solid and the control will begin modulating the output as required. Any
system errors are indicated by a fast blinking LED (about twice per second) for instance when the discharge air sensor is disconnected or outside of the
normal operating range.
Calibration
The temperature control should maintain an accuracy of +/- 3°F (1°C). In the event that the discharge is inaccurate due to duct losses the control may be
calibrated in two ways. The potentiometer on the face of the DFC labeled “ADJUST” will adjust the discharge temperature by +/- 10°F (5°C) when
rotated. Rotating it clockwise will increase the temperature and counter clockwise will decrease the temperature. The system may also be adjusted from
the DFTD if installed by adjusting potentiometer R3 on the back in the same manner as the DFC procedure above.
Troubleshooting
The DFC control provides some diagnostics via the on board LED labeled “POWER/STATUS”. A system fault is indicated by a fast blinking LED (about
twice per second). This usually indicates 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 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 as stated below.
For DFC-1 and DFC-2
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