Fuses; Connection Points And Wiring; Solenoid Valves - Cleveland steamcraft 21-CET-8 Service Manual

Page 78 Model 21 -CET-8 Service Manual

Fuses

Connection Points and Wiring

Solenoid Valves

If a fuse is blown and there is no other apparent damage, replace the fuse and try to
start the unit. This blown fuse may be the only damage. Normal current flow through
a fuse over time can weaken the fuse, eventually causing it to blow. If the
replacement fuse blows immediately, some other trouble exists. The unit must then
be thoroughly checked before trying to restart it.
Any component malfunction can result from loose connections or open wiring. Be sure
to check for these conditions before replacing any component,
Discoloration of wire insulation near connection points usually indicates loose
connections. Current flow through loose connections causes oxidation and increased
resistance of the connection. The resistance can increase to a point where the
connection can no longer dissipate the heat generated and the terminal bums.
High-current connections, such as at the terminal block and contactor terminals, are
particularly susceptible to damage when loose. Using wire that is too small in diameter
a also yields the same results. Be sure that any wiring meets the amperage
requirements of the circuit.
All connections should have no resistance and measure 0 VAC across them. Any
voltage reading greater than 0 VAC across a connection indicates a faulty connection
and must be corrected.
The SteamCraft 3.1 uses some pressure type connections. Be sure to tighten screw
and nut connections securely and that threads are not cross threaded. Special care
must be used to secure the high voltage contactor connections. If loose, these high
current connections will bum or explode and cause extensive damage.
All solenoid valves in the SteamCraft: 3.1 energize. to open the valves. The solenoid
energizes at a nominal 120 VAC. Power applied to a properly operating solenoid
causes an audible click sound. While energized, the solenoid hums at low volume.
The click sound usually indicates a properly operating valve. If water does not flow
with the valve energized, check for a solenoid valve stuck dosed, dogged inlet or
outlet in the valve body or in the plumbing external to the valve. Check that external
supply valves are open.
If water flows through the valve when the solenoid is deenergized, check for a stuck
open valve, worn valve seat, or foreign material blocking valve closure.
When testing or replacing any solenoid valve, check the valve for correct flow
direction. Markings on the valve body indicate IN for the inlet, OUT for the outlet, or
both. Some valves may use an arrow to indicate the proper flow direction. Valves
installed backwards will not work correctly.
Energized solenoids generate a magnetic field that can be detected with a steel
screw driver. Note that some stainless steels, brass, and aluminum alloys are not
magnetic and will not sense the magnetic field.
Printed 12/90