State Industries SHE50-100NE, SHE50-100PE manual AIR Pressure Switch Testing, Normal State Test

Page 22

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

AIR PRESSURE SWITCH TESTING

Air pressure switch testing involves three procedures:

Normal State Test

Operational State Test

Pressure Test

Normal State Test

Turn off power and disconnect the wires to the pressure switches. Wrap electrical tape around the wire ends to prevent shorts. A continuity test is performed, using an ohm meter, between the wiring terminals of the switch. The Blower Prover switch has normally open contacts. The Blocked Intake and Blocked Exhaust switches have normally closed contacts.

If this test confirms the Blower Prover switch contacts are open and the Blocked Intake/ Exhaust switch contacts are closed - the switches have passed the test. If test results indicate the Blower Prover switch contacts are closed - the switch must be replaced. If either the Blocked Intake or Exhaust switch contacts are open - the switch must be replaced.

Operational State Test

The operational test is also a continuity test performed with an ohm meter between the pressure switch wiring terminals. However, this test is performed while the blower is running during the pre-purge mode. Ensure the wires to the air pressure switches are disconnected and that electrical tape is wrapped around the wire ends to prevent shorts. Perform a continuity test between the wiring terminals on the air pressure switches with the blower running (water heater in pre-purge mode).

During this test the normally open contacts of the Blower Prover switch should close. The Blower Prover switch “activates” (closes its contacts) during normal operation to verify or “prove” that the blower is running. If the contacts remain open during this test the third test, the pressure test, must be performed to determine if the pressure switch is defective. During this test the Blocked Intake and the Blocked Exhaust switch contacts should remain closed, if the contacts open during this test the third test, the pressure test, must be performed to determine if the pressure switch is defective.

Technical Literature Department

21 of 52

Ashland City, TN © 2008

Servicing should only be performed by a Qualified Service Agent

 

Image 22
Contents Service Handbook Ultra High Efficiency Power VENT/POWER Direct Vent Service Warning Qualifications Qualified Service AgentImportant Service Reminder Tools Required Closed Water Systems Thermal ExpansionAIR Requirements Contaminated AIRVenting Maximum Equivalent Length RequirementsMaximum Elbow Requirements Service Notes VentingPipe Size Requirements Number Maximum Pipe Elbows Length Feet MetersCorrectly Wired Outlet Service Notes ElectricalVAC 1Ø Power Supply Electrical RequirementsHOW IT Works Internal ViewService Notes Blower BlowerService Notes Burner Flame Sensor BurnerBurner & Blower Removal On NextService Notes Blower Flange & Blower Adapter Gaskets Burner/Blower RemovalVenturi BlowerGas Valve Removal GAS ValveGasket Orifice GAS Pressure Testing Service Notes Checking Gas PressuresGAS Pressures Service Notes Gas Pressure AdjustmentGas Pressures AIR Pressure Switches Normal State Activated StateBlocked Intake Switch Blower Prover SwitchBlocked Exhaust Switch AIR Pressure Switch Operation Blower Prover FailureNormal State Test AIR Pressure Switch TestingOperational State Test Pressure Test Air Pressure Switch ParametersBlower Prover Blocked Intake Blocked Exhaust Page Measuring Flame Sensing Current Flame Sensing TestFlame Sensor Service Notes Hot Surface Igniters Igniter Current TestControl System Features IntroductionService Notes Button Pad Ribbon Cable UIMCommercial & Residential Product Differences Discreet Menu Contact InformationService Note Sequence of Operation Display Desktop ScreenStatus Icons Status Icon DescriptionOperational States Modes State DescriptionOperating SET Point Adjustment Action DisplayControl System Menus ECO Service Notes CCB Replacement CCBJ10 J13 J15 J11 J16 Socket IdentificationJ2 Socket 120 VAC To Blower J3 Socket 120 VAC Power SupplyJ1 Socket Transformer PIN # DescriptionRetry Ext Use Yes Input Type Tstat OpenWiring Diagram Service Notes Polarity & GroundSequence of Operation YESRough Starting Rough Operation Note Resetting the control systemImportant Service Reminder Heater Status MenuUIM is Inoperable Control System UnresponsiveUIM Display Is Blank Displayed Message CHECK/REPAIR CONDITION/INDICATESFault Messages AC ReversedFlame Probe Short Upper Probe ShortFlame Detect Error Energy Cut Out ECOBlocked Inlet Blocked Exhaust Vent Blower Prover Open Perform ALL These Tests with PowerTurned on and a Call for Heat Active Low Igniter Current Ignition Failure Rough Starting Rough Operation NoteCheck for 24 VAC to the Gas Valve solenoid coil Gas Valve Failure Communication FailureTennessee Waltz Parkway Ashland City, TN