Maxitrol SC20C User Manual

SC20C Series

Signal Conditioner with
Discharge Air Temperature Limiter

For direct or indirect fired gas applications, the track mounted
SC20C Series performs multiple functions. The control will
convert a controller's DC output signal of 4 to 20 milliamps or 0 to
10 volts to a 0 to 20 volt DC signal used to drive the Maxitrol
Selectra

temperature regardless of the controller supplied input. Three
discharge temperature ranges are available and are selectable
using a 3-pin header. The temperature is set within the selected
range using the onboard potentiometer. Temperature is
measured using a TS194/TS194Q with MT Series mixing tube.

5 psi (350 mbar) inlet pressure, 30,000 CFH (850 m
maximum, and pipe sizes from 3/8" to 4". (For additional valve
information see Bulletin MT2035, or consult your Maxitrol sales
representative.)

®

valve.

It will also limit the heater's maximum selected discharge air

Modulator and modulator-regulator valves are available up to

3

/h)

Three Position DIP Switch

4-20 mA

all positions on

ON

0-10 V

23

1

all positions off

SC20_MS_EN_08.2006

Dimensions: 7.5" L x 3.38" W x 2.09" H

SIGNAL CONDITIONER:

Ambient Limits...............-40o to 150oF (-40o to 66oC)

SIGNAL CONDITIONER POWER REQUIREMENTS:

24V AC transformer, 20 VA capacity (50/60 Hz).
(No grounded secondary.)

LIMITS DISCHARGE AIR TEMPERATURE:

Three Temperature Ranges: Jumper Pins

o

80

to 130oF (27o to 54.5oC) None
110o to 160oF (43o to 65.5oC) 2 & 3
150o to 200oF (65.5o to 93oC) 1 & 2

CONNECTIONS:

1/4" Spade

Wiring Diagram

B

1

T

24 VAC

POWER

1 2 3 4 5 (-) 6 (+)

24VAC

20VA

VALV E

OUTPUT

M OR MR

Valve

SENSOR

T2 T1

J1

1

3

TS194(Q)

23555 Telegraph Rd., P.O. Box 2230

© 2006 Maxitrol Company, All Rights Reserved.

Maxitrol Company

Southfield, MI 48037-2230 U.S.A.

248.356.1400 • Fax [phone]

SIGNAL IN

Controller

(Note Polarity)

INPUT

Unit

TO AVOID INTERNAL DAMAGE TO THE SC20C SERIES
SIGNAL CONDITIONERS FOLLOW THESE GUIDELINES:

Transformer secondary must not be grounded in any

1.
portion of the circuit external to the SC20C Series signal

conditioners. If existing transformer is grounded, a
separate isolated transformer must be used.

Multiple SC20C Series signal conditioners controlled

2.
by a signal source with common outputs (terminals 5 &

6) require separate transformers for each SC20C
Series signal conditioner.

Multiple SC20C Series signal conditioners powered by

3.
a single transformer require isolated signal inputs
(terminals 5 & 6) to each SC20C Series signal
conditioner.

www.maxitrol.com

IMPORTANT - READ PRIOR TO INSTALLATION

Mertik Maxitrol

European Representatives

Warnstedter STrasse 3 06502 Thale, Germany

49.3947.400.0 • Fax [phone]

Industriestrasse 1 48308 Senden, Germany

49.2597.9632.0 • Fax [phone]