Installation, Operation
4
and
cas
PQ435-1
(Supersedes PQ435)
RENEWAL PARTS IDENTIFICATION
161-562795-001
JUNE, 1994
Type CAS-20CM Electric Steam Boiler
(Standard Trim is 100 PSI — 0-90 PSI Operating Pressure Range)
Boiler Serial No. ______________________________________________ Power Circuit Voltage __________________________
Model No. ___________________________________________________ Control Circuit Voltage__________________________
National Board No. ____________________________________________ Amps ___________Phase __________Cy __________
IMPORTANT – This data file contains the National Board Registration Certificate approving your boiler. It must be kept near the boiler at all
times.
Model
CAS-20CM
Note: Control circuit 120V
© 2010 Chromalox, Inc.
Electric Capacity
BHP Rating
Voltage
Phase
Amperes Drawn
Contactor
50A, 4 Pole
20 kW
2.0
208
1
96
16/20 kW
1.6/2.0
208/230
3
45/51
60A, 3 Pole
20 kW
2.0
240
1
84
50A, 4 Pole
20 kW
2.0
346
3
34
40A, 3 Pole
20 kW
2.0
380
1
53
60A, 2 Pole
20 kW
2.0
480
3
24
30A, 3 Pole
INSTALLATION
3. When any type of feed other than a pump feed is used, the
water supply line pressure must be 10 pounds greater than the
boiler operating pressure to assure proper water level in boiler.
Lack of water can cause heater failure. Keep feed water line
valves open at all times.
4. Connect steam line (with outlet valve) to boiler steam outlet.
5. Open all gauge valves and steam outlet valve; keep drain valve
closed.
Note: The safety valve should be provided with a drain line
sized no less than the outlet size of the valve and routed per
local codes.
6. Floor drain to be provided directly below unit.
WARNING: To avoid electrical shock hazard, boilers
must be suitably grounded to earth.
Note: Chromalox boilers are pre-tested before shipment; no internal piping or wiring is necessary. WARNING: Substitution of
components or modification of wiring without prior consent of
Chromalox voids warranty.
1. Bolt unit securely to level floor or platform.
Note: A minimum distance of 18 inches from wall, other
equipment, etc. must be allowed for removal of the elements.
2. Complete all piping to boiler. Connect water line to tagged fitting on the motor and pump assembly if used, or to tagged fitting on water control feeder.
Type CAS
Electric Steam Boiler
WIRING
tectors should be installed per manufacturer’s recommendations at your service entrance.
4. Be sure that all electrical connections are sufficiently tightened. Loose connections will cause overheating and damage to
the electrical wiring.
5. Special instructions for customers supplying their own condensate or pump system.
A. Check the voltage of the motor before making the wiring
connection. The motor should always match the voltage of
the control circuit. Standard control circuit voltage is 120
volts ± 10 volts.
B. Internal water feed relay is rated at a maximum of 1/3 H.P.,
120 volts. Motors rated greater than 1/3 H.P., or other than
120V, single phase, require the use of a suitable motor starter.
6. After all service connections are made, open feed water supply
valve and energize the boiler. The feed water solenoid will
open, fill the boiler to the proper water level and automatically shut off. The feed solenoid will continuously cycle on and
off as the boiler requires water. If, for any reason, the water
drops below the minimum safe operating level, the boiler’s
electrical circuits, except the feed solenoid will be de-energized automatically. Upon refilling to the proper level, the
boiler will automatically restart.
WARNING: Hazard of Electrical Shock. Disconnect
all power before working on boiler. Boilers must be
grounded in accordance with the National
Electrical Code (NEC) standards to avoid shock
hazard.
WARNING: Use 90°C copper conductors only.
1. Select proper wire gauge and type for supply conductors in
accordance with the National Electrical Code and local wiring
codes following wiring diagram supplied (See recommendations for disconnect switches and fusing).
Note: Purchaser should use a safety disconnect employing circuit breakers or fuses between the main power source and the
boiler. This overcurrent protection should be installed in addition to any other supplementary fuses or circuit breakers provided as an integral part of the boiler.
2. If a separate control circuit is used, the control circuit should
be connected to the control terminal block and the circuit protected by overcurrent devices in accordance with the National
Electrical Code.
3. Chromalox boilers are solid state devices. Since boilers are
connected to water lines, these devices are susceptible to voltage surges and lightning damage. Industrial type lightning pro-2-
SCHEMATIC WIRING DIAGRAM
Wire Color Code —
B = Black
W = White
R = Red
O = Orange
Y = Yellow
GR = Green
BL = Blue
HTR
O
OPERATION
once a day. In soft water areas, once each week. If water is known
to be corrosive, consult water treating specialists to recommend
water treatment needed to insure corrosion free boiler operation. If
there is a particular problem which applies to your own local water
condition other than mineral content, take this into consideration
in determining what schedule is to be followed.
1. At the end of the working day turn switch to the OFF position
and close water supply valve. De-energize wall mounted safety switch (main power supply).
2. If blowing down into a receptacle, cover receptacle to prevent
splash of scalding water.
3. It is preferable to connect the blowdown valve directly into a
drainage system. If this is done, the boiler can be discharged at
operating pressure. However, check local codes and suitability
of drainage system before connecting.
4. When blowdown is complete and boiler is drained (a) close the
blowdown valve; (b) open water supply valve; (c) put boiler
switch in the ON position; and, (d) close wall mounted safety
switch.
5. When refilling is complete, turn off the boiler switch unless
further operation is desired.
SOLID STATE FLOATLESS LIQUID LEVEL
CONTROL SYSTEM
This boiler is equipped with a solid state, floatless liquid level
control which operates by sensing the electrical resistance of
water. Note: Control will not work with de-ionized or demineralized water. Two probes are provided. The HI probe activates and
controls the feed water relay. The LOW probe is a safety back-up
probe that turns off the power to the element in the event of low
water. A 12 volt potential is established between each probe and
ground. The presence or absence of water generates a small signal
that is amplified and fed to a SCR. The SCR, in turn, activates a
relay, depending on the function and the water level.
ADJUSTING PRESSURE CONTROLS
Chromalox boilers are supplied with operating and high limit pressure controls. One is used for controlling the operating pressure of
the boiler while the other is used as a high limit control.
MANUAL BLOWDOWN INSTRUCTIONS
Blowdown is an essential part of boiler operation. It is the best
preventive maintenance you can give your boiler and will add
years of life to the unit. Make sure a blowdown schedule is established and followed regularly.
Blowdown will remove accumulated hard water scale and dislodge scale from water heating surface thereby insuring efficient
heating. In extremely hard water areas blowdown is necessary
The use of chemical boiler cleaning compounds in these boilers
voids all warranties unless approved by Chromalox, Inc.
-3-
MAINTENANCE
Normal Operation Sequence.
1. Water drops below HI probe. After 10 second delay, water feed
energizes refilling boiler.
2. Water reaches HI probe and turns off water feed.
3. Sight glass should be 1/3 to 1/2 full. Heater contactor will cycle at
operating pressure depending on load. Heater contactor should
not chatter on short cycle. In the event of contactor chatter,
check for low water condition and check for damaged or shorted probes.
Inconsistent water level causing low water cutoff.
1. Test feed solenoid control circuit by energizing control circuit.
Remove cover plate from probes.
2. Check for shorted or failed water feed probes.
3. Check water feed lines, valves and circuits.
WARNING: Hazard of Electric Shock. Disconnect all
power before working on boiler.
1. A monthly inspection should be made to ensure that all electrical connections are tight.
2. When steam or water leaks are observed, fittings should be
tightened immediately.
3. Every four months, the Solid State Liquid Control probes
should be checked for deposits and cleaned if necessary.
Remove deposits from probe and teflon sleeve. This is accomplished by removing the inspection plate and with the use of a
standard spark plug wrench, removing the probes. Care should
be taken during the removal and reinstallation of the probes so
the porcelain insulator is not damaged.
The feed water probe is mounted in a surge isolator tube. This
isolator tube should be removed and cleaned at the same time
as the probes.
Note: Make sure that probe does not touch the insulator tube,
as grounding will occur. This will cause boiler to run dry.
4. At the same time, remove the heating element and inspect for
scale formation. If scale has begun to form, clean element and
also flush boiler.
INSTRUCTIONS FOR ELEMENT REPLACEMENT
Note: Element failure is usually caused by excessive scale build
up or low water operating conditions. Before replacing element, be
sure boiler tank is clean and free of scale. Check control board,
water feed system and control probes for proper operation.
Failure to perform the above maintenance checks may result in
immediate burn-out of new elements.
1. A monthly inspection of the boilers, boiler installation and
electrical wiring should be made to insure proper operation.
These inspections should include:
A. Electrical connections. Look for overheated or discolored
power terminals. Check and tighten all terminals that may
work loose from expansion and contraction.
B. Check for steam or water leaks and tighten all pipe fittings.
C. Check safety relief valve.
D. Check water feed line, strainers and check valves.
E. Blow down boiler and make sure drain lines are clear.
Read completely before starting work.
1. Disconnect boiler from electric power supply at main safety
switch or fuse panel. Then turn boiler switch to “off” position.
2. On automatic feed units, close valve on incoming water line.
Drain boiler completely of water.
3. Remove wiring compartment end panel to expose heating element.
4. Disconnect wire (electric) leads connecting element to main
power system of boiler. Again note wire connections to facilitate re-assembly. Proceed to remove (6) 5/16-18 bolts from
flange.
5. Thoroughly clean boiler flange of all foreign material. Be certain no part of old gasket remains on boiler flange.
6. Apply “Slic-Tite” Gasket Compound (or equivalent) to both
surfaces of new gasket supplied with replacement element.
Proceed to install element flange assembly with gasket
between boiler flange and element flange. In doing this, be
careful to align flange holes; element flange is marked “TOP”
so wire connection terminals on top element assembly will be
in line with previously disconnected wire leads to facilitate
easy connections.
7. When all (6) flange bolts are tight, connect all wires to terminals. Make certain wires are clean and bright to assure good
electrical contact and nuts on screws are firmly secured.
Note: Bolts should be tightened to a torque of 22 ft. lbs.
8. Open water valve so water supply can reach boiler feed mechanism.
9. Put main safety switch to “ON” position.
10. Turn boiler switch to “ON” position.
11. As boiler automatically refills, observe the new flange assembly for possible leaks. If water is noticed, the bolts must be
retightened. Before doing this, turn the boiler off at the main
fuse safety switch.
12. As boiler is heated to working pressure, check flange assembly
again for leaks.
WARNING: Avoid use of chemical cleaning compounds. Follow maintenance instructions.
TROUBLE SHOOTING HINTS
1. Boiler does not energize when main switch is turned on (nothing happens).
A. Check to see if main power is turned on.
B. Check to see if control circuit voltage is turned on. (ONOFF switch has a pilot light)
C. Check power and control circuit fuses or breakers.
D. Check control circuit fuse on boiler.
E. Check all electrical connection for tightness.
2. Boiler power control circuit pilot light is on. Boiler will not fill
or heat.
A. No water in boiler. Check sight glass, it should be 1/8 to 1/2
full. Check water feed lines, valves, pumps, strainer, etc. for
proper operation.
B. Solid state water feed probe inoperative. Check solid state
liquid controls probes. Water feed solenoid should activate
10 seconds after control circuit is turned on. Clean probe
and isolator tube as required. Make sure probe is straight
and does not touch wall.
C. Water feed relay bad – replace plug-in relay.
D. Solenoid valve bad — replace solenoid valve.
3. Boiler has power and water in sight glass. Boiler will not heat.
A. Bad heating contactor. Check for open coil or frozen contacts.
B. Bad relay on control Board. Replace control board.
C. Burned out element. Replace heating element.
D. Loose power connection. Tighten electrical connections.
4. Boiler floods.
A. Check high water probe and isolator tube for deposits.
B. Check water feed relay for frozen contacts.
C. Check solenoid valve, may be stuck or damaged.
5. Element repeatedly burns out.
A. Low water cutoff probe damaged or shorted to ground.
Remove and check low probe.
B. Boiler not supplied with water. Check water feed lines,
valves and circuits. Check water feed probe.
C. Control board defective. Check operation of board and
component. Replace board if necessary.
6. Control board trouble shooting. Start-up sequence.
The two probe board has the following sequence of operation
when the boiler is initially energized.
A. Turn on control circuit power.
B. Approximately 10 second delay before water feed solenoid
or pump starts.
C. Water rises in boiler and contacts low probe which closes
relay contacts, turning on heater.
D. Water continues to rise to HI probe. Turns off water feed.
-4-
RENEWAL PARTS IDENTIFICATION
HEATING ELEMENTS
Description
PRESSURE CONTROLS
Part Number
20kW 240V 1PH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20kW 208V 1-3PH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
155-300121-006
155-554735-023
16/20kW 208/230V 3PH . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20kW 346V 1-3PH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
155-554735-024
155-554735-051
20kW 380V 1PH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20kW 480V 3PH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
155-554735-042
155-554735-030
Element Gasket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Element Bolt (6 Req’d.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
132-146012-001
345-072565-428
Description
Operating Pressure Control Auto Reset . . . . . . . . . . . . . . . . .
High Limit Pressure Control – Auto Reset . . . . . . . . . . . . . . .
VALVES AND GAUGES
Description
ELECTRICAL COMPONENTS
Description
Part Number
Rocker Switch with Pilot (ON/OFF) . . . . . . . . . . . . . . . . . . . .
Contactor 30A, 3 pole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
292-053223-002
072-047913-020
Contactor 40A, 3 pole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contactor 50A, 4 pole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
072-047913-012
072-047913-021
Contactor 60A, 2 pole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contactor 60A, 3 pole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
072-047913-026
072-047913-016
Fuse Holder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Terminal Block, Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
129-300029-001
303-075444-001
Terminal Block, Power (1 PH only) . . . . . . . . . . . . . . . . . . . .
303-047468-003
Fuse 15A, 250V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
128-072576-027
Description
334-300032-004
344-118536-005
Drain Valve 1/2” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Solenoid Valve, 120V, 1/4” NPT . . . . . . . . . . . . . . . . . . . . . . . .
344-121194-006
344-121780-012
Strainer 1/4” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pressure Gauge, 1/4”, 0-160 PSIG . . . . . . . . . . . . . . . . . . . . .
351-118664-003
130-118661-001
SOLID STATE LEVEL CONTROL PARTS
Part Number
Sight Glass O-Rings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Valve Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
132-073284-001
344-120970-003
Sight Glass Protector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
334-056360-002
Nipple, Conduit 1” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
198-300084-004
-5-
Part Number
Probe Level Control, 53/8” . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Probe, Cutoff, 57/8” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
242-300036-010
242-300036-011
Control Board with Relay (2 probe) . . . . . . . . . . . . . . . . . . . .
Control Board* (1 probe) . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Control Board* (3 probe) . . . . . . . . . . . . . . . . . . . . . . . . . . . .
323-300033-001
323-300033-011
323-300033-006
Relay for Control Board, Plug-in . . . . . . . . . . . . . . . . . . . . . .
Spark Plug . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
072-300047-001
346-300035-001
Probe Isolator (For Level Control) . . . . . . . . . . . . . . . . . . . . .
332-300009-002
*Used on older models.
374-121046-021
Part Number
Safety Valve 1/2”, 100 PSIG . . . . . . . . . . . . . . . . . . . . . . . . . . .
Check Valve 3/8” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Description
GAUGE GLASS PARTS
Sight Glass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Part Number
292-300031-001
292-300031-001
Limited Warranty:
Please refer to the Chromalox limited warranty applicable to this product at
http://www.chromalox.com/customer-service/policies/termsofsale.aspx.
2150 N. RULON WHITE BLVD., OGDEN, UT 84404
Phone: 1-800-368-2493
www.chromalox.com