Bryant 355CAV installation instructions Sequence of Operation, Purge Gas Lines

Page 48

355CAV

Purge Gas Lines

If not previously done, purge the lines after all connections have been made and check for leaks.

!WARNING

FIRE AND EXPLOSION HAZARD

Failure to follow this warning could result in a fire, explosion, personal injury, or death.

Never purge a gas line into a combustion chamber. Never test for gas leaks with an open flame. Use a commercially available soap solution made specifically for the detection of leaks to check all connections.

Step 3 — Sequence of Operation

!CAUTION

UNIT OPERATION HAZARD

Failure to follow this caution may result in intermittent unit operation.

Furnace control must be grounded for proper operation, or control will lock out. Control is grounded through green/yellow wire routed to gas valve and burner box screw.

Using the schematic diagram (See Fig. 48), follow the sequence of operation through the different modes. Read and follow the wiring diagram very carefully. ! !

NOTE: If a power interruption occurs during a call for heat (W/W1 or W/W1-and-W2), the control will start a 90-second blower-only ON period two seconds after power is restored, if the thermostat is still calling for gas heating. The amber LED light will flash code 12 during the 90-second period, after which the LED will be ON continuous, as long as no faults are detected. After the 90-second period, the furnace will respond to the thermostat normally.

The blower door must be installed for power to be conducted through the blower door interlock switch ILK to the furnace control CPU, transformer TRAN, inducer motor IDM, blower motor BLWM, hot surface igniter HSI, throttling valve TV, and gas valve GV.

Single-Stage Thermostat and Step-Modulating Heating

(Adaptive Mode)

See Fig. 29 or Fig. 59 for thermostat connections.

NOTE: Low-heat only switch SW1-2 selects the low-heat only operation mode when ON. Medium-heat only switch SW4-2 selects medium-heat only operation mode when ON. If both switches are ON the furnace control will default to medium-heat. If either or both switches are ON the furnace control will operate at two-stages only as referenced in Section 2 below. If both switches are OFF the furnace control will operate in the adaptive heating mode in response to a call for heat. (See Fig. 33.) When the W2 thermostat terminal is energized it will always cause high-heat operation as long as the R to W circuit is closed, regardless of the setting of the low-heat or medium-heat only switches.

This furnace can operate as a step-modulating furnace with a single-stage thermostat because the furnace control CPU includes a programmed adaptive sequence of controlled operation, which selects low-heat, medium-heat, or high-heat operation. This selection is based upon the stored history of the length of previous gas-heating periods of the single-stage thermostat.

The furnace will start up in either medium-, or high-heat. The furnace will operate in low-heat after starting and operating for 1 minute at medium-heat before transitioning to low-heat. The furnace control CPU determines the combined low-heat and medium-heat on-time (from 0 to 16 minutes) which is permitted before switching to high heat.

If the power is interrupted, the stored history is erased and the furnace control CPU will select medium-heat for 1 minute, low-heat for 15 minutes and then switch to high-heat, as long as the thermostat continues to call for heat. Subsequent selection is based on stored history of the thermostat cycle times.

The wall thermostat ”calls for heat”, closing the R to W circuit. The furnace control CPU performs a self-check, verifies the low-heat and medium-heat pressure switch contacts LPS and MPS are open, then de-energizes the HPSR relay to close the NC contact.

1.Inducer Prepurge Period - The furnace control CPU turns on inducer motor IDM and slowly increases the inducer motor speed. After the low-heat pressure switch LPS closes the furnace control CPU continues to increase the inducer motor speed until the medium-heat pressure switch MPS closes. When the medium-heat pressure switch MPS closes, throttling valve TV is energized, in- ducer motor RPM is noted by the furnace control CPU, and a 25-second prepurge period begins. The RPM is used to evaluate vent system resistance. This evaluation is then used to determine the required RPM necessary to op- erate the inducer motor during medium-heat prepurge, the first minute of medium-heat mode, and low-heat mode.

NOTE: The heat cycle can start in either high- or medium-heat. If a high-heat cycle is initiated, the furnace control CPU will continue to increase the inducer motor speed after the medium-heat pressure switch MPS closes. When the medium-heat pressure switch closes, throttling valve TV is energized, inducer motor RPM is noted by the furnace control CPU, and a 25-second prepurge period begins. The RPM is used to evaluate vent system resistance. This evaluation is then used to determine the required RPM necessary to operate the inducer motor in high-heat pre-purge, and high-heat mode.

2.Igniter Warm-Up — At the end of the prepurge period, the Hot-Surface Igniter HSI is energized for a 17-second igniter warm-up period.

3.Trial-For-Ignition Sequence — When the igniter warm- up period is completed the main gas valve relay contact GVR closes to energize the gas valve solenoid GV-M. The gas valve solenoid GV-M permits gas flow to the burners where it is ignited. Five seconds after the GVR closes, a 2- second Flame-Proving period begins. The HSI igniter will remain energized until flame is sensed or until the 2-second flame proving period begins.

If the furnace control CPU selects high-heat operation, the high-heat gas valve solenoid GV-HI is energized when the high-heat pressure switch HPS closes.

4.Flame-Proving — When the burner flame is proved at the flame-proving sensor electrode FSE, the furnace control CPU begins the blower-ON delay period and continues to hold the gas valve GV-M open. If the burner flame is not proved within two seconds, the furnace control CPU will close the gas valve GV-M, and the furnace control CPU will repeat the ignition sequence for up to three more Tri- als-For-Ignition before going to Ignition-Lockout. Lock- out will be reset automatically after three hours, by mo- mentarily interrupting 115 vac power to the furnace, or by interrupting 24 vac power at SEC1 or SEC2 to the furnace control CPU (not at W/W1, G, R, etc.).

If flame is proved when flame should not be present, the furnace control CPU will lock out of Gas-Heating mode

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Contents Installation Instructions Required Notice for Massachusetts Installations Table of Contents Safety ConsiderationsDimensions In. / mm Environmental Hazard355CAV Clearances to Combustibles Electrostatic Discharge ESD Precautions Codes and StandardsIntroduction Unit Damage HazardApplications Upflow ApplicationProperty Damage Hazard Condensate Trap Alternate Upflow Orientation Carbon Monoxide Poisoning HazardCondensate Trap Tubing Alternate Upflow Orientation Upper Inducer Housing Drain Connection Condensate Trap Field Drain AttachmentCondensate Trap Freeze Protection Downflow Applications Condensate Trap LocationHorizontal Left Tube Configuration Horizontal Left SUPPLY-AIR Discharge ApplicationsCombustion AIR Intake Vent Property Damage Construct a Working PlatformUnit Operation Hazard Horizontal Right SUPPLY-AIR Discharge Applications Condenste Trap Field Drain AttachmentProhibit Installation on Back LocationFire or Death Hazard Hazardous LocationsFIRE, EXPLOSION, Injury or Death Hazard Installation Installation in Upflow or Downflow ApplicationsInstallation in Horizontal Applications Leveling Legs If DesiredFurnace, Plenum, and Subbase Installed on a Angle AIR Ducts Fire Hazard FIRE, Carbon Monoxide and Poisoning HazardUnit MAY not Operate Gas Piping Fire or Explosion HazardRemoving Bottom Closure Panel Wiring Electrical Shock HazardDisconnect Switch and Furnace Electrical Shock and Fire HazardAccessories Fire or Electrical Shock HazardRemoval of Existing Furnaces from Common Vent Systems AIR for Combustion and Ventilation Fire and Explosion HazardCombustion-Air and Vent Pipe Diameter Pipe Fittings Cement Description Marked on PrimersFurnace Control Direct Vent Termination Clearance Ventilated Combustion Air Vent Termination Clearance Vent Pipe Termination for Ventilated Combustion Air System Combustion AIR Pipe Unit Corrosion HazardAttachment of Combustion Air Intake Housing Plug Fitting Combustion Air Termination Ventilated Combustion Air OptionVent Pipe Combustion Air Termination-Direct Vent / 2-Pipe SystemCarbon Monoxide Poisoning Property Damage Hazard Attachment of Vent Pipe304.8mm minimum 76.2mm minimum Vent Termination Extended Exposed Sidewall PipesVent Termination Kit Direct Vent / 2-Pipe System Only Two-Pipe Termination Kit Direct Vent / 2-Pipe System OnlyWinter Design Maximum Allowable Pipe Length Ft M Number of 90 Elbows BtuhDirect Vent 2-Pipe Only Condensate Drain Multi-venting and Vent TerminationsApplication Personal Injury HazardSTART-UP, Adjustment and Safety Check Air Conditioning A/C Setup SwitchesContinuous Fan CF Setup Switches Additional Setup Switches SW4Example of Setup Switch in Off Position Prime Condensate Trap with WaterWiring Diagram Inducer Housing Drain Tube Furnace Setup Switch DescriptionSequence of Operation Purge Gas LinesTwo-Stage Thermostat and Two-Stage Low / High Heating Two-Stage Thermostat and Two-Stage Medium/High HeatingThermidistat Mode Super Dehumidify Mode Continuous Blower ModeContinuous Blower Speed Selection from Thermostat Heat PumpStep-Modulating Furnace with Single-Speed Air Conditioning Pump Furnace and Two-Speed Air Conditioner Furnace and Two-Speed Heat PumpSet Gas Input Rate Redundant Automatic Gas ValveBurner Orifice Altitude AVG. GAS 675 Altitude Derate Multiplier for USA Burner FlameSet Temperature Rise Gas Rate cu Ft/HrSet Thermostat Heat Anticipator Checklist Check Safety ControlsCheck Pressure Switches Check Primary Limit ControlChecklist Installation Combustion and Vent PipingCatalog No. II355CAV---060---4
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355CAV specifications

The Bryant 355CAV is a state-of-the-art automated vertical machining center designed to enhance precision and efficiency in the manufacturing sector. Renowned for its robust construction, this machine is engineered to handle a broad spectrum of machining tasks, making it suitable for both small and large-scale production environments.

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In summary, the Bryant 355CAV is a versatile, high-performance machining center that showcases cutting-edge features and technologies. Its combination of user-friendly controls, sturdy construction, energy efficiency, and advanced monitoring positions it as a vital asset for manufacturers aiming to elevate their productivity and precision in an increasingly competitive landscape.
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