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AIR INLET PRESSURE SWITCH REPLACEMENT --
Air pressure switch should come with switching limit preset. Changing adjustment on
switch, could allow heater operation without adequate air flow, resulting in damage to
heating system components.
1. Check label (12) on new pressure switch (6). Label should be marked 1823--1. If marking is not as stated
obtain correct pressure switch.
2. Apply anti--seizing tape to threads of elbows (9 and 10).
3. Install elbows (9 and 10) into pressure switch (6) and orient as shown.
4. Thread pressure switch (6) onto sub--panel (11)
5. Connect tubes (7 and 8) to elbows (9 and 10).
6. Remove screw (4), then remove cover (5) from pressure switch (6).
7. Connect wires to pressure switch (6) as tagged.
8. Install cover (5) onto pressure switch (6), then secure with screw (4).
9. Close door (2) and secure to heater enclosure (3) by tightening four latches (1).
When testing heating system to ensure proper setting on air pressure switch, air flow will be
partially blocked off. If heating system does not automatically stop with in five seconds
remove blocking device from air inlet. Allowing heater to operate for extended periods
without adequate air flow could result in damage to heating system components.
10. Test heating system as follows:
a. Place a piece of cardboard (or other suitable blocking device) over air inlet screen (13).
b. Use maintenance menu to start heating system (WP 0010 00).
c. Verify heating system starts then turns off and a BURNER BLWR IN PRESS LO fault is
d. Remove cardboard from air inlet screen (13).
e. Use maintenance menu to test heating system (WP 0010 00). Verify normal operation
END OF WORK PACKAGE