Pressure Switch Tests; Continuity Test During Standby - State Water Heaters 60120-100250 Service Handbook

PRESSURE SWITCH TESTS

Complete pressure switch testing involves three procedures:
• "Continuity Test During Standby" below.
• "Continuity Test During Operation" on Page 13.
• "Pressure Test During Operation" on Page 13 thru Page 15.

CONTINUITY TEST DURING STANDBY

This test is performed while the Combustion Blower is not running with the water heater turned off. This is a
"normal state" continuity test of the contacts inside each pressure switch. Disconnect the two wires to each
pressure switch for this test.
1. If the water heater is in a heating cycle lower the Operating Set Point to end the cycle.
2. Turn off the circuit breaker that serves the water heater.
3. Disconnect both wires at each pressure switch.
4. Using an ohm meter set for continuity testing, check for continuity between the two wiring terminals at
each pressure switch, see Figure below.
5. After completing the tests, confirm that all of the pressure switch wires are reconnected including the
replacement part if necessary based on the Results/Actions listed below. Restore the electrical power
to the water heater. Reset the Operating Temperature Set Point if it was adjusted. Run the water heater
through a complete heating cycle before leaving to ensure it is operating properly.
Results/Actions
Passed Results: If the Blower Prover switch contacts are open during this test (infinite ohms/open circuit)
the Blower Prover switch has passed the test. If the Blocked Air Intake Switch and Blocked Exhaust Switch
contacts are closed during this test, (zero ohms/direct short), these switches have passed the test.
Failed Results: If the Blower Prover switch contacts are closed (zero ohms/direct short/beep) during this
test, the Blower Prover switch must be replaced. If the Blocked Air Intake Switch and/or Blocked Exhaust
switch contacts are open during this test, the switch(s) must be replaced.
Proceed to the Continuity Test During Operation on next page.
12 Servicing should only be performed by a Qualified Service Technician