Lochinvar SNA400-125, SNA500-125, SNR200-100, SNA285-125 Sequence of operation, HTR Ignition

Page 49

TM

Installation & Service Manual

11 Operating information (continued)

Sequence of operation

 

 

OPERATION

DISPLAY

 

 

 

1.

When the tank temperature falls below the set point minus the

HTR: Standby

 

differential, the control will start the burner.

TANK: 123.8F(129)

 

 

 

2. The control connects 120 VAC to the blower. The blower does not

 

 

run at this time.

HTR: Standby

 

•

The manual reset high limit must be closed before the control

 

 

powers up the blower.

TANK: 123.8F(129)

 

•

The control starts the internal pump.

 

 

•

If there is an external limit connected to the heater, it must be

 

 

 

closed.

 

 

 

 

3.

The control then starts a 10 second prepurge cycle.

HTR: PREPURGE

 

 

 

TANK: 123.9F(129)

4.

Once the prepurge cycle is complete, and the blocked drain

HTR: IGNITION

 

switch and auto-reset high limit are closed, the control starts the

 

5 second trial for ignition by sending spark voltage to the spark

TANK: 123.9F(129)

 

electrode and opening the gas valve.

 

 

 

5.

If the control does not detect flame by the end of the trial for

HTR: POSTPURGE, PREPURGE

 

ignition, the control performs a 10 second postpurge, another

 

prepurge and tries to light the burner again. If the burner does

TANK: 123.9F(129)

 

not light after 4 trials, the control locks out for 1 hour and then

 

 

tries another set of 4 trials.

 

 

 

 

6.

If the control detects a flame before the trial for ignition ends, it

HTR: RUN 20% RATE

 

begins to modulate the burner in order to maintain the set point.

TANK: 124.8F(129)

 

 

 

7.

Once the tank temperature goes 3 - 4°F above the set point, the

HTR: POSTPURGE

 

control will turn off the burner. The blower will remain on for the

 

10 second postpurge cycle. The internal pump will continue to

TANK: 127.4F(129)

 

run for its pump delay time, then turn off.

 

 

 

8.

Burner off.

HTR: Standby

 

 

 

TANK: 124.7F(129)

49

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Contents What to do if YOU Smell GAS Installation & Service ManualContents Hazard definitions Please read before proceedingBlower Shield How it worksModels SNR150-100 -- SNA285-125 Model SNA500-125 Model SNA400-125CSA RatingsCloset and alcove installations Installation must comply withDetermine water heater location Before locating the water heater, check1Closet Installation Minimum Required Clearances Remove water heater from wood pallet Flooring and foundationPrevent combustion air contamination Do not install the Shield water heater into 3Combustion Air Direct from Outside Minimum Recommended Combustion AIR Supply to Equipment Room Direct venting options General ventingCanada Venting and combustion airVent pipe and fittings Air inlet pipe materials Air intake/vent connectionsRemoving from existing vent Vent LengthVent and air piping Sidewall direct venting If using the alternate sidewall terminationVent/air termination sidewall Vent Size2Clearance to Gravity Air Inlets Prepare wall penetrations Alternate Field Supplied Option Prepare wall penetrationsTermination and fittings 5AMultiple Vent Terminations must also comply with -1A Multiple vent/air terminationsSidewall termination optional concentric vent Sidewall termination installationDescription and usage 9Concentric Vent Dimensional Drawing Multiventing sidewall terminations 12Concentric Vent Sidewall AttachmentVent/air termination vertical Vertical direct venting2Vertical Terminations with Multiple Water Heaters Prepare roof penetrationsVertical termination optional concentric vent Vertical termination installationMultiventing vertical terminations 6Concentric Vent Roof Installation1Vertical Direct Venting w/Room Air Conventional and sidewall ventingSystem water piping methods System pipingScalding General piping informationWater chemistry Piping componentsDelta T Single Unit 3Multiple Units Water Tank Supply Gas connections Connecting gas supply pipingPropane gas Natural gasCheck inlet gas supply Natural Gas Pipe Capacity ChartLength of Pipe in Straight Feet for 1/2 PSI Gas pressure Gas valve replacementField wiring 3Low Voltage Field Wiring Connections Inputs Condensate drain Condensate disposalCheck for gas leaks Inspect/fill condensate system Start-upFinal checks before starting the water heater If water heater does not start correctly Start the water heaterCheck system and water heater Check flame and combustion2Operating Instructions Models SNR150-100 -- SNA285-125 3Operating Instructions Models SNA400-125 -- SNA500-125 Protection features Temperature controlOperating information GeneralAdjustable control parameters Water heater temperature regulationSaving parameters HTR Ignition Sequence of operation1Control Panel Shield control moduleStatus Display Screens Status display screensStatus Display Screens cont’d Service technician Maintenance Maintenance and annual startupOwner maintenance Maintenance Check water system Flue vent system and air pipingCheck expansion tank Check water heater relief valveCheck all water heater wiring Check ignition ground wiring Check burner flameCheck control settings Check flame signalHandling ceramic fiber materials Cleaning heat exchangerOiled bearing circulators Niosh stated First AidBefore troubleshooting TroubleshootingCheck control module fuses Check the followingNo Burner Operation No DisplayUnit Does Not Modulate Above 50%Temperature F Resistance Ω Checking temperature sensorsTroubleshooting Sequence FlameNo Flame Ign Running No FlameGV/Relay FailHigh Limit Manual ResetFan Low Fan Speed LowFan High SwitchFan Speed High Sensor OpenProgr ParametersWatch Dog Error Service BlkLow 24 VAC Write EEPromGas Valve Adjustment Combustion Analysis ProcedureOr Obstruction Gas Supply PressureModels SNR150-100 -- SNA285-125 Gas valve adjustment procedureModel SNA400-125 Model SNA500-125120 VAC DiagramsLOW Voltage

SNA400-125, SNR150-100, SNA285-125, SNR200-100, SNA500-125 specifications

Lochinvar has established itself as a leader in the realm of high-efficiency heating solutions, and its line of condensing boilers, including the SNA500-125, SNR200-100, SNA400-125, SNA285-125, and SNR150-100, exemplifies the brand’s commitment to innovation, efficiency, and reliability.

The SNA500-125 model stands out with its impressive heating capacity, designed for larger commercial applications. Featuring advanced modulating burners, it can precisely adjust its output based on real-time demand, significantly enhancing energy efficiency. The stainless steel heat exchanger ensures robust durability and improved thermal performance, while the integrated controls offer advanced diagnostic capabilities and user-friendly operation.

Next in the lineup, the SNR200-100 serves as a versatile option for mid-sized applications. Its compact design allows for flexible installation, making it a valuable choice for facilities with limited space. The boiler incorporates a high-efficiency combustion system that maximizes fuel utilization, while its low NOx emissions technology aligns with environmental standards, reducing the carbon footprint of users.

The SNA400-125 delivers a robust solution for diverse heating needs, equipped with state-of-the-art modulation technology that not only optimizes efficiency but also offers quiet operation – a crucial feature for facilities where noise reduction is paramount. This model also includes built-in redundancy options, enhancing reliability during peak operational periods.

The SNA285-125 provides a balance of performance and efficiency for smaller commercial settings. Its innovative control system offers precise temperature management and easy integration with existing systems. Energy Star certified, this model is not only cost-effective but supports sustainability efforts in various industries.

Lastly, the SNR150-100 is ideally suited for light commercial applications, featuring a compact footprint and excellent heat transfer capabilities. The user-friendly interface and robust safety features make it an excellent choice for operators prioritizing both ease of use and reliability.

All these models incorporate Lochinvar's commitment to superior design and advanced technologies, setting a benchmark in the high-efficiency heating market. With a focus on long-term performance and compliance with modern environmental standards, Lochinvar continues to deliver top-tier solutions tailored to meet diverse customer needs. Whether for large-scale operations or smaller settings, these boilers represent a significant advancement in commercial heating technology.
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