Raypak 503-2003 Installation And Operating Instructions Manual page 39

Fig. 36: Air Pressure Switch
Blocked Vent Switch
This heater is equipped with a blocked vent pressure
switch to prevent the operation of the heater when too
much of the vent is blocked. This switch is located on
the right side of the heater near the right rear corner.
Fig. 37: Blocked Vent Switch
UDB Diagnostic Board
This heater is equipped with a diagnostic board which
will indicate faults as they occur. It has the ability to
retain up to 256 faults in history. Refer to the Trouble-
shooting section for instructions on accessing,
reviewing and clearing these faults.
SW1
SW2
Fig. 38: UDB Diagnostic Board
37
SECTION C: Installation