SC30 Series Signal Conditioners
W (L2)
6
5
7
8
X2
24 VAC
3
2
SC30 Power Relay
SC30
10
11
1
X1
12
Maxitrol�
Modulating�
Valve
�
�
9 4
+
-
�
�
Temperature�
Controller Input�
0-10 VDC�
(Polarity Sensitive)
W
120 VAC
B
B (L1)
Room Thermostat
W
Inducer
R
Low
High
B
Inducer Relay
Inducer Relay
Time Delay Relay
Time�
Delay�
Relay
High Gas Valve Relay
X2
SC30�
Relay
5
6
24 VAC
X1
W
120 VAC
B
High Gas Valve Relay
High Gas Valve
HI
GR
Ignition Control
COM
FS
GR
C
SC30 Power Relay
Combination Gas Valve
W
PS1
PS2
C
C
MV
GR
MV
IND
L1
For Indirect Fire Gas Applications Using 2-speed Inducers and 2-stage Gas Valves
DESCRIPTION
The track mounted SC30 Series controls three functions:
1) Converts a controller’s DC output signal of 0-10 volts to
a 0-20 VDC signal to provide compatibility with Maxitrol’s
M/MR Series gas valves.
2) Controls the normally open relay used to switch inducer
speed and gas valve stage. Closes or opens the relay based
on controller’s DC output to the SC30.
Relay closes at approximately 5.3 VDC input
Relay opens at approximately 4.7 VDC input
3) Provides an adjustable timer SC30 (0-30 sec) or xed time,
SC30-XXX: specied in 15 second increments (beginning
with 45 seconds - 045) and adjustable VDC (5-15 VDC)
output to the modulating gas valve on startup (powering of
SC30). The feature eliminates problems associated with
lighting the burner at its lowest gas input.
Adjustment potentiometers:
R18 0-30 second timer (SC30 only)
R22 5-15 VDC output voltage (All)
Additional relays and timers external to SC30 can be replaced
with TR1 - Timer Relay Control. See TR1_MI_EN_12.2006.
Modulator and modulator-regulator valves are available up
to 5 psi (350 mbar) inlet pressure, 30,000 CFH (850 m3/h)
maximum, and pipe sizes from 3/8” to 4”. (For additional valve
information see Bulletin MT2035, or consult your Maxitrol sales
representative.)
DIMENSIONS: 4.75" W x 3.38" H x 2.09" D
SIGNAL CONDITIONER:
Ambient Limits ................. -40º to 150ºF (-40º to 66ºC)
SIGNAL CONDITIONER POWER REQUIREMENTS:
24 VAC transformer, 20 VA capacity (50/60 Hz).
(No grounded secondary.)
READ PRIOR TO INSTALLATION: To Avoid Internal Damage
to SC30 Series Signal Conditioners Follow These Guidelines.
1. Transformer secondary must not be grounded in any
portion of the circuit external to the SC30 Series signal
conditioners. A separate, independent transformer is
recommended.
2. Multiple SC30 Series signal conditioners controlled by
a signal source with common outputs (terminals 7 & 8)
require separate transformers for each SC30 Series signal
conditioner.
3. Multiple SC30 Series signal conditioners powered by a
single transformer require independent signal inputs (ter-
minals 7 & 8) to each SC30 Series signal conditioner.
Figure 1: Wiring Diagram
Maxitrol Company
23555 Telegraph Rd., P.O. Box 2230
Southeld, MI 48037-2230 U.S.A.
SC30_MS_EN_08.2008
www.maxitrol.com
© 2008 Maxitrol Company,
All Rights Reserved.