GENERAL DESCRIPTION

GENERAL DESCRIPTION
Sales Manual Section 180
PRODUCT SPECIFICATION ZT-100
High Temperature
Shutdown System
Model ZT-100
GENERAL DESCRIPTION
The ZT-100 Series self-actuated Temperature Shutoff
System offers an improved means of monitoring heated
liquid temperatures and initiating preventative action in
the event of a temperature overshoot or accidental
damage to the system. It is installed in connection with
controlled water heaters of the storage or instantaneous
type (see "Instantrol" Heater Package), where an extra
degree of precaution against the discharge of
overheated liquid is important.
The ZT-100 system consists of a single-seated
diaphragm control valve, a temperature sensitive pilot
with a manual relatch feature, and a combination
pressure regulators trainer-relief valve. The system
operates on the cold water supply pressure and requires
no electrical or pneumatic supplies. Loss of cold water
supply closes the system down. Piping is completed at
installation as illustrated in Fig. 1A or B.
SPECIFICATIONS
PILOT VALVE:
Type: ..............................................................Three-way
Ends: ...............................................................1/2" NPT
Port: ....................................................................... 3/16"
Medium: ........................................................Cold water
Thermal System: ..............................................Fail-Safe
Capillary: ..................................... 6 ft. standard, copper
Bulb: ........................ 12B (bushed) 1/2" x 3-7/8" copper
Well: .... Available on order in S. S. 1/2" NPT mounting
thread, 4-7/32" insertion.
Range Selection:
100 - 128°F
125 - 140°F
135 - 165°F
160 - 190°F
180 - 210°F
Setpoint: ........................................................Adjustable
VC231A-MA
HOW TO ORDER
Specify:
1. Control valve size.
2. Pilot range and setpoint.
3. Medium.
4. Supply pressure and pressure drop through control
valve.
DIAPHRAGM SHUTOFF VALVES (VC231A-MA)
REGULATOR/STRAINER RELIEF VALVE
REGULATOR:
Ends: ...............................................................1/2" NPT
Range: ........................................................... 10-25 psig
(factory set 12 psig)
Max. Pressure: ..................................................125 psig
RELIEF VALVE:
Ends: ...............................................................1/2" NPT
Pressure Setting: ................................................ 30 psig
1
LINE
SIZE
VALVE
SIZE
MATERIAL
MAX. SUPPLY
MAX.
BODY TRIM WATER STEAM PRESSURE
DROP
3/4"
3/4"
BZ
SS
250
250
250
1"
1"
BZ
SS
250
250
250
1-1/4"
1-1/4"
BZ
SS
250
250
250
1-1/2"
1-1/2"
BZ
SS
250
250
250
2"
2"
IRON
SS
125
125
125
OPERATION
DIMENSIONS
With the temperature sensing bulb of the pilot installed
in the heated water line, the latched open pilot supplies
a 12 or 20 psi pressure to the shutoff valve diaphragm
so that the valve remains in the full-open position.
If the shutoff valve is installed in the heated medium
line, liquid is allowed to flow on demand as long as the
temperature at the pilot sensing bulb is below the pilot
setpoint. If the liquid temperature exceeds the setpoint,
the pilot vents the pressure on the shutoff valve
diaphragm and the shutoff valve immediately closes
and stops the liquid flow. The condition causing the
over-temperature must be corrected and the pilot
manually relatched before monitored service is
restored.
If the shutoff valve is installed on the heating medium
supply line, then the supply to the heater is shut off
when or if a temperature over-run is detected at
sensing bulb, but the liquid flow is not affected.
Damage or failure of the thermal system of the pilot
results in closure of the shutoff valve on either line.
SHUTOFF VALVE DIMENSIONS
Fig. 1A - With Shutoff valve installed in steam supply line.
VALVE
DIMENSION
SIZE
A
B
K
E
F
3/4"
14-5/16" 10-7/8" 9-1/2" 6-15/16" 1"
14-5/16" 10-7/8" 9-1/2" 7-1/8"
1-1/4"
1-1/2"
2"
14-1/2"
15"
10-7/8" 9-1/2"
10-7/8" 9-1/2"
15-13/16" 10-7/8" 9-1/2"
G
-
H
-
J
-
L
-
-
-
-
-
7-1/2"
-
-
-
-
-
8-1/2"
-
-
-
-
-
4"
5/8"
7"
6" 4-3/4" 3/4"
Fig. 1B - With Shutoff valve installed in hot water discharge line.
NOTE: Setpoint must be higher than ambient temperature surrounding the
pilot and its capillary. Pilot and its sensing bulb should be installed several
feet downstream from heater outlet.
2
Q-4052 (5/01)
Printed in U.S.A.
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