Air Pressure Switches - A.O. Smith BTX-100 Service Handbook

ULTRA HIGH EFFICIENCY POWER VENT/POWER DIRECT VENT - SERVICE MANUAL

AIR PRESSURE SWITCHES

Air pressure switch technical bulletins TB-A023-06 and TB-S023-06 explain air pressure
switch construction and test procedures in detail. These technical bulletins are available on
the manufacturers web site or by calling the technical support phone number shown on the
water heater labeling. Construction and types of air pressure switches used on the water
heater covered in this Service Manual are shown below.
(open switch contacts)
Blower Prover
Air Pressure Switch
Normally open contacts,
close on a rise in pressure.
Blocked Intake
Air Pressure Switch
Normally closed contacts,
open on a fall in pressure.
Blocked Exhaust
Air Pressure Switch
Normally closed contacts,
open on a rise in pressure.
Technical Literature Department
Construction
Normal State
Switch Contacts
Internal Linkage
Flexible Diaphragm
Application & Type
Normal State
Servicing should only be performed by a Qualified Service Agent
Activated State
(closed switch contacts)
Wiring Terminals
Vent Port
Sensing Port
18 of 52
Activated State
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