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Servicing should only be performed by a Qualified Service Technician

BLOWER PROVER SWITCH

The blower prover switch is provided on the heater to verify that the fan is operating. It is a positive pressure 

switch whose electrical contacts are 

normally open

. The blower prover switch electrical contacts will 

close 

on a rise in pressure

 as the blower increases the pressure in the burner. This switch is connected to the 

blower outlet pressure tap by a piece of silicone tubing. This tubing must be connected in order for the switch 

to close the electrical contacts.

BLOCKED OUTLET SWITCH

The blocked outlet switch electrical contacts are 

normally closed

. The blocked outlet switch electrical 

contacts will 

open on a rise in pressure

.

 

HIGH LIMIT SWITCH/ DIGITAL THERMOSTAT

The digital thermostat contains the high limit (energy cut out) switch. The high limit switch interrupts burner 

gas flow should the water temperature reach 203°F (95°C).
In the event of high limit switch operation, the water heater cannot be restarted unless the water temperature 

is reduced to approximately 120°F (49°C). The manual reset button on the front of the control then needs to 

be depressed.
Continued manual resetting of high limit control, preceded by higher than usual water temperature is evidence 

of high limit switch operation.
Contact your dealer or qualified service technician if continued high limit switch operation occurs.

Temperature  

Adjustment 

Dial

Display 

LED Label

Display LED's

To Lower (E4) 

Temperature 

Probe

To Pressure Switch, I/O Modules & Ignition Control (E1)

Fuse

To 120V 

supply 

(E2)

Manual 

Reset

To Upper (E3)Temperature Probe

Summary of Contents for SBL85275NE

Page 1: ...CING SHOULD ONLY BE PERFORMED BY A QUALIFIED SERVICE TECHNICIAN Service Handbook COMMERCIAL GAS WATER HEATERS FOR MODELS SBL85275NE A SBL85310NE A SBL85366NE A SBL85390NE A ULTRA LOW NOx SERIES 104 IN...

Page 2: ......

Page 3: ...OF OPERATION FLOW CHART 17 SEQUENCE OF OPERATION FLOW CHART 18 LIGHTING AND OPERATING LABEL 19 TROUBLESHOOTING 20 CONTROLS OVERVIEW CONTROL BOX ASSEMBLY 21 PRESSURE SWITCHES ALL MODELS 22 HIGH LIMIT...

Page 4: ...Qualified Agency Any individual firm corporation or company that either in person or through a representative is engaged in and is responsible for 1 the installation testing or replacement of gas pip...

Page 5: ...s required for testing pressure switches and can replace a gas pressure gauge draft gauge or slack tube manometer for checking gas pressure UEi model EM200 or equivalent Water pressure gauge w lazy ha...

Page 6: ...ration 3 Check the operation of the limit and operating controls 4 Check the vent system seams and joints and ensure that there is no discharge of flue products into the room 5 Check the input rate Su...

Page 7: ...the installed space The vent system on one or more gas fired appliances can experience down drafts due to the outdoor air pressure being greater than the ambient air pressure in the installed space Wh...

Page 8: ...ommunicate with the outdoors and must communicate through a vertical or horizontal duct to the outdoors or spaces crawl or attic that freely communicate with the outdoors and must have a minimum free...

Page 9: ...ue to thermal expansion Thermal expansion can cause premature tank failure leakage This type of failure is not covered under the limited warranty Thermal expansion can also cause intermittent Temperat...

Page 10: ...ef Valve Upper Thermostat Probe ECO Lower Thermostat Probe Control Box Assembly Drain Valve Combustion Blower Burner Assembly Gas Control Valve Clean Out Cover The Eliminator Exhaust Vent Combustion A...

Page 11: ...rom the blower at the gas valve flange by unscrewing the 4 retaining screws Keep the o ring that is located in the flange groove This o ring seals the flange to the gas valve 5 Remove the 4 fasteners...

Page 12: ...ew burner gasket over the three studs extending from the flange plate 17 Install the adapter tube on the flange plate with the 3 brass locknuts Torque the nuts to 60 in lb 18 Install the new skirt rin...

Page 13: ...The spark gap between the spark rod and grounding rod is 1 8 FLAME SENSOR This water heater is equipped with a flame sensor The flame sensor senses flame by passing a small electric current through t...

Page 14: ...low Figure and Table In all installations the minimum combustible clearances from vent piping shall be 6 15 2 cm Vent piping passing through a combustible wall or ceiling must be a continuous run no j...

Page 15: ...s the required clearances for venting units using natural draft venting The vent must extend at least 3 feet above the highest point where it passes through a roof of a building and at least 2 feet hi...

Page 16: ...0 1 Ft 8 8 8 7 7 6 6 310 000 2 Ft 8 8 8 7 7 7 6 6 310 000 3 Ft 8 8 8 7 7 7 6 6 Number of Heaters Combined Input in Thousands of Btu hr Manifold and Common Vent Diameters Inches 2 620 000 12 10 10 9 9...

Page 17: ...Diameter Inches 0 6 6 6 6 5 5 5 5 2 7 7 7 6 6 6 6 5 4 7 NA NA NA NA NA NA NA 5 NA 7 7 6 6 6 6 5 6 7 NA NA NA NA NA NA NA 8 NA 7 NA NA NA NA NA NA 10 NA NA 7 6 6 6 6 6 15 NA NA NA 7 6 6 6 6 20 NA NA NA...

Page 18: ...or does not detect proper flame the Ignition Control shuts off the Gas Valve and allows the Blower to purge the unit At that time the Ignition Control restarts with step 6 It will try and ignite the m...

Page 19: ...17 Servicing should only be performed by a Qualified Service Technician DIAGNOSTIC SEQUENCE OF OPERATION FLOW CHART...

Page 20: ...18 Servicing should only be performed by a Qualified Service Technician SEQUENCE OF OPERATION FLOW CHART...

Page 21: ...t causing property damage personal injury or loss of life BEFORE OPERATING ENTIRE SYSTEM MUST BE FILLED WITH WATER AND AIR PURGED FROM ALL LINES A B This appliance does not have a pilot It is equipped...

Page 22: ...ency Check gas input If incorrect check for inlet air blockage and or flue gas exhaust blockage Water temperature too hot Thermostat set too high Set thermostat to a lower setting Rumbling Sediment ac...

Page 23: ...d by a Qualified Service Technician CONTROLS OVERVIEW CONTROL BOX ASSEMBLY Variable Frequency Drive Digital Thermostat Ignition Control Blocked Outlet Switch Blower Prover Switch ON OFF Switch High Sp...

Page 24: ...ation of the unit The switches are wired to the Ignition control in series It is important to understand the purpose of each switch PRESSURE SWITCHES PRESSURE SWITCHES Model Setpoint WC Tolerance WC B...

Page 25: ...pen on a rise in pressure HIGH LIMIT SWITCH DIGITAL THERMOSTAT The digital thermostat contains the high limit energy cut out switch The high limit switch interrupts burner gas flow should the water te...

Page 26: ...ut Out has opened Check for excessively hot water 203 F or higher Check the resistance of the temperature probes and continuity of the high limit ECO No power Check the breaker Tank is at a set temper...

Page 27: ...uity is indicated ZERO 0 0 Resistance Opens at 203 F closes at 193 F If water is below 193 F continuity is correct Continuity is not present meter reads 0 L Replace ECO sensor if water temperature is...

Page 28: ...Temperature Probe continuity check Red wire to red wire Turn supply power Off for this test IF THEN Test indicates no continuity Replace probe Continuity is indicated Probe should be okay also verify...

Page 29: ...inuity check Red wire to red wire Turn supply power Off for this test IF THEN Test indicates no continuity Replace probe Continuity is indicated Probe should be okay also verify Ohms resistance for wa...

Page 30: ...o ignite the burner three times before lockout The control waits 15 minutes before trying again to ignite the burner This is a continuous cycle This is a 24 VAC ignition control The microprocessor cir...

Page 31: ...VFD speed signals are de energized immediately FAILURE TO LIGHT LOCKOUT MULTI TRIAL CONTROL Should the burner fail to light or if flame is not detected during the first trial for ignition period the g...

Page 32: ...ad control check LED for steady on or flashing code see above Table d Pressure switch contacts did not close Tubing or wire off pressure switches 2 Thermostat on no spark a Miswired b No 24V AC power...

Page 33: ...lower motor The VFD receives a signal from the thermostat and ignition control that instructs the VFD to transmit the proper frequency to the blower to produce the proper blower speed and proper input...

Page 34: ...rive Line supply is at the top of the drive the motor power supply is at the bottom of the drive VFD BLOWER SPEED AND FREQUENCY READINGS The logic inputs for the VFD are sent from the thermostat and i...

Page 35: ...33 Servicing should only be performed by a Qualified Service Technician WIRING DIAGRAM SBL85275NE A THRU SBL85390NE A...

Page 36: ...link of www statewaterheaters com for a listing of available Service Handbooks For additional information contact State Water Heaters 500 Tennessee Waltz Parkway Ashland City TN 37015 1 800 527 1953 w...

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