Slant/Fin SC-3 User Manual

FOR GAS-FIRED, OIL FIRED AND DUAL FUEL HOT WATER HEATING PLANTS

SC-3 Controller

MODULAR BOILER CONTROLLER SERIES

INSTALLATION AND OPERATING INSTRUCTIONS

SC-3 Applications

• Space Heat Systems With Outdoor Reset

• Constant Temperature Setpoint Control

CONTENTS

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

a) Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

b) Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

c) View of Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

d) System Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Select System Type . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

A. Space Heating Only with Outdoor Reset . . . . . . .12

a) Dip Switch Settings . . . . . . . . . . . . . . . . . . . . . .12

b) Functions and Defaults . . . . . . . . . . . . . . . . . . . .13

c) Adjusting the Settings . . . . . . . . . . . . . . . . . . . . .13

B. Space Heating Only w/Setpoint Control . . . . . . . .17

a) Dip Switch Settings . . . . . . . . . . . . . . . . . . . . . . . . .17

b) Functions and Defaults . . . . . . . . . . . . . . . . . . . . . .18

c) Adjusting the Settings . . . . . . . . . . . . . . . . . . . . . . .20

Viewing the Performance . . . . . . . . . . . . . . . . . . . . . . . . .22

Useful Hints and Reloading Factory Defaults . . . . . . . .23

Testing the Contol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

Error Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

Factory Default Listings . . . . . . . . . . . . . . . . . . . . . . . . . .28

If your system is different than the above, call the Slant/Fin

technical services group at 800-873-4346 to

determine the proper control.

The SC-3 is a microprocessor control which will sequence up to
three heating stages based on outdoor air temperature and supply
water temperature. Designed to handle a Caravan gas-fired,
oil-fired or *dual fuel-fired hot water heating plant for space
heating or “Setpoint” operation. A large easy to read display
provides current system temperatures and operating status.

ADDITIONAL FUNCTIONS INCLUDE:
Pump exercising. Pump purging. Boiler demand for space heating
loads. Set point demands for set point loads. Test sequence to
ensure proper component operation. CSA C US certified. Setback
input for energy savings.

SPACE HEATING OPERATION: When the outdoor air tempera­ture drops below a preset value, the heating system is energized.
The SC-3 Controller determines the number of stages required to
meet the space heating needs and fires them. During operation,
the Controller scans system temperatures, adding or deleting
stages as necessary to satisfy heating load.

Controller Packing List

1- SC-3 Modular Controller P/N 435081
1- Outdoor sensor with enclosure P/N 339070
1- Universal sensor P/N 339071

SETPOINT OPERATION:
The SC-3 adds and deletes stages to minimize the difference
between the desired Setpoint temperature and the actual
measured Supply Water Temperature.

Dual-Fuel
* Not available in Canada

Printed in U.S.A. 605 PUBLICATION SC-3-40
Part No. 435083000

3 SC-3 Controller

INSTALLATION

CAUTION

Improper installation and operation of this control could result in damage to the equipment and possibly even personal injury. It is your
responsibility to ensure that this control is safely installed according to all applicable codes and standards. This electronic control is not
intended for uses as a primary limit control. Other controls that are intended and certified as safety limit must be placed into the control
circuit. Do not open the control. Refer to qualified personnel for servicing. Opening voids warranty and could result in damage to the
equipment and possibly even personal injury.

CONTROL PANEL MOUNTING

The control panel is to be mounted in an indoor area where the ambient temperature range will be 30 to 120˚F (0 to 50˚C) and less that
95% RH. Power Supply is to be 115 V (ac) +/- 10% 50/60 Hz 600 VA.

The installer must ensure that this control and its wiring are isolated and/or shielded from strong sources of electromagnetic noise.
Conversely, this Class B digital apparatus complies with Part 15 of the FCC Rules and meets all requirements of the Canadian Interference­Causing Equipment Regulations. However, if this control does cause harmful interference to radio or television reception, which is deter­mined by turning the control on and off, the user is encouraged to try and correct the interference by re-orienting or relocating the receiving
antenna, relocating the receiver with respect to the control, and/or connecting the control to a different circuit from that to which the receiver
is connected.

WARNING: The nonmetallic enclosure does not provide grounding between conduit connections. Use grounding type bushings and jumper
wires as needed.

Press down at the fingertip
grips on top of the front cover
and pull out and down.

Remove the safety dividers
from the wiring chamber by
pulling them straight out of their
grooves.

The control can be mounted on
a standard DIN rail. First
remove the control from its
base and then, using the hooks
and spring clip on the back of
the control, mount it onto the
DIN rail. This will be a popular
option for those who prefer to
mount the control inside a larg­er electrical panel.

Lift the front cover up and away
from the control.

Press the control release clip
on the base inside the wiring
chamber and slide the control
upwards.

Loosen the screws at the front
of the wiring cover.

The control lifts up and away from
the base.

The wiring can enter the bottom or
the back of the enclosure. Knock­outs provided in the base allow the
wiring to be run in conduit up to the
enclosure. The base also has holes
that line up with the mounting holes
of most common electrical boxes.

The wiring cover pulls straight
out from the wiring chamber.

The base is ready for mounting.

SC-3 Controller 4

INSTALLING THE SENSORS
OUTDOOR SENSOR SF P/N 339070

MOUNTING THE SENSOR

Note: The temperature sensor (thermistor) is built into the enclosure.

• Remove the screw and pull the front cover
ff the sensor enclosure.

o

• The enclosure can either be mounted directly

onto a wall or a 2” x 4” electrical box.
When it is wall mounted, the wiring
should enter through the back or bottom
of the enclosure. Do not mount the enclosure
with the conduit knockout facing upwards
as rain could enter the enclosure and
damage the sensor.

• In order to prevent heat transmitted through the wall from affecting the sensor reading, it may be necessary to install and insulating

barrier behind the enclosure.

• The sensor should be mounted on a northern wall of the building. It should not be exposed to heat sources such as ventilation or

window openings. Caution
temperatures that are not high enough to meet the demand.

: If sunlight strikes the sensor enclosure or the surface area surrounding it, the system will provide water

• It should be installed at an elevation above the ground that will prevent accidental damage or tampering.

WIRING AND TESTING THE SENSOR

• Connect 18 AWG or similar wire to the two terminals provided in the enclosure and

run the wires from the sensor to the control. Do not run the wires close to and parallel to
telephone or power cables. If the sensor wires are located in an area with strong sources
of electromagnetic interference (EMI), shielded cable or twisted pair should be used or the
wires can be run in a grounded metal conduit. If using shielded cable, the shield wire
should be connected to the Com Sen terminal on the control and not to earth ground.

• Follow the sensor testing instruction that follows and connect the wires to the control.

• Replace the front cover of the sensor enclosure.

UNIVERSAL SENSORS

MOUNTING THE SENSOR SF P/N 339071

Note: These sensors are designed to mount in an immersion well or on a pipe.

For example - If a Sensor is mounted onto a 1” type L copper pipe, there is approximately an 8 second delay between a sudden change in
water temperature and the time the sensor measures the change. This delay increases considerably when steel pipe is used.

It is strongly recommended that an immersion well be used, especially when steel pipe of greater than 1-1/4” is used and also
when large diameter pipes are used and fluid stratification is probable.

Sensor Mounted In Immersion Well
SF P/N 410569

5 SC-3 Controller

The Universal Sensor can be
strapped directly to the pipe using
the cable tie provided. Insulation
should be placed around the sensor
to reduce the effect of air currents on
the sensor measurement. The flat

ortion of the sensor should be mounted

p
against the pipe.

The Universal Sensor should be placed
downstream of a pump or after an elbow
or similar fitting. This is especially impor­tant if large diameter pipes are used as
the thermal stratification within the pipe
can result in erroneous sensor readings.
Proper sensor location requires that the

luid is thoroughly mixed within the pipe

f
before it reaches the sensor.

WIRING AND TESTING THE SENSOR

WARNING: Do not run sensor wires close to and parallel to telephone or power cables. If the sensor wires are located in an area with

strong sources of electromagnetic interference, shielded cable or twisted pair should be used or the wires can be run in a grounded metal
conduit. If using shielded cable, the shield wire should be connected to the Com Sen terminal on the control and not to earth ground.

• It is necessary to connect 18 AWG wire to the two sensor wires. Wire nuts can be used to hold the wires together.

• Follow the sensor testing instructions that follow and then connect the wires to the control.

SENSOR TESTING INSTRUCTIONS

A good quality test meter capable of measuring up to 5,000 kΩ (1 kΩ = 1000 Ω) is required to measure the sensor resistance. In addition
to this, the actual temperature must be measured with either a good quality digital thermometer, or if a thermometer is not available,
a second sensor can be placed alongside the one to be tested and the readings compared.

First measure the temperature using the thermometer and then measure the resistance of the sensor at the control. The wires from the
sensor must not be connected to the control while the test is performed. Using the chart below, estimate the temperature measured by
the sensor. The sensor and thermometer readings should be close. If the test meter reads a very high resistance, there may be a broken
wire, a poor wiring connection or a defective sensor. If the resistance is very low, the wiring may be shorted, there may be moisture in
the sensor or the sensor may be defective. To test for a defective sensor, measure the resistance directly at the sensor location.

Do not apply voltage to a sensor at any time as damage to the sensor may result.

Temperature Resistance Temperature Resistance Temperature Resistance Temperature Resistance

˚F ˚C  ˚F ˚C  ˚F ˚C  ˚F ˚C 

-50 -46 490,813 20 -7 46,218 90 32 7,334 160 71 1,689

-45 -43 405,710 25 -4 39,913 95 35 6,532 165 74 1,538

-40 -40 336,606 30 -1 34,558 100 38 5,828 170 77 1,403

-35 -37 280,279 35 2 29,996 105 41 5,210 175 79 1,281

-30 -34 234,196 40 4 26,099 110 43 4,665 180 82 1,172

-25 -32 196,358 45 7 22,763 115 46 4,184 185 85 1,073

-20 -29 165,180 50 10 19,900 120 49 3,760 190 88 983

-15 -26 139,402 55 13 17,436 125 52 3,383 195 91 903

-10 -23 118,018 60 16 15,311 130 54 3,050 200 93 829

-5 -21 100,221 65 18 13,474 135 57 2,754 205 96 763
0 -18 85,362 70 21 11,883 140 60 2,490 210 99 703
5 -15 72,918 75 24 10,501 145 63 2,255 215 102 648

10 -12 62,465 80 27 9,299 150 66 2,045 220 104 598
15 -9 53,658 85 29 8,250 155 68 1,857 225 107 553

SC-3 Controller 6

7 SC-3 Controller

WIRING THE SYSTEM

Use one of the following wiring diagrams to wire your system, along with the appropriate diagram on page 9.

1. Gas fired - Space Heating only

. Oil fired - Space Heating only

3

If using MM 750P-MT120 L.W.C.O. use Figure C6

on page 9 to wire the control

1. Gas fired - Space Heating only

NOTE: For boiler termination wiring at modules, see page 9

SC-3 Controller 8

2. Oil fired - Space Heating only

NOTE: For boiler termination wiring at modules, see page 9

9 SC-3 Controller

SC-3 Controller 10

DISPLAY:

Symbol Description

Stage

Displays which stage relays are turned on.

Pump

Displays when the primary pump relay is turned
on.

˚F, ˚C, min, hr

Units of measurement.

Occupied Schedule

Displays when the control is in Occupied Mode.

UnOccupied Schedule

Displays when the control is in UnOccupied
Mode.

Installer Access Level

Displays when the Installer/Advanced Dip
switch is set to Installer

Pointer

Displays the control operation as indicated by
the text.

Warning/Alarm

Displays when an error exists or the alarm relay
is turned on.