Thomas & Betts UDAP, UDAS dimensions Combustion Air Proving Switch Pressure Switch

Page 17

Make sure that the heat anticipator setting on the thermostat is 0.6 amps (or in accordance with the amperage value noted on the wiring diagram of your heater).

Make thermostat connections at the terminal strip on the back of the heater. The strip has four terminals, R, G, W1, and W2; refer to the wiring diagram.

FIGURE 13 - Terminal Strip for 24-volt wiring is on the outside rear of the heater

NOTE: The size of heater illustrated has a vertical terminal strip. Some sizes have a horizontal terminal strip.

Rear View - Model UDAP

Terminal

Strip R

G

W1

W2

Supply

Wiring

Entrance

Rear View - Model UDAS

Terminal

Strip R

G

W1

W2

Built-in

Disconnect

Switch

Supply

Wiring

Entrance

Unit Mounted

Thermostat -

Option CM3

Multiple Heater

Control - Option

CL31 and Option

CL32

16.Combustion Air Proving Switch (Pressure Switch)

If the heater was ordered with Option CM3, a kit for mounting the thermostat on the rear of the heater is shipped separately. Follow the instructions in the option package to attach the bracket.

Select a snap-action thermostat when using the unit mounted thermostat bracket. Do not use a mercury switch thermostat because the vibration may cause exces- sive unit cycling. Be careful with the thermostat leads; shorting the thermostat wires to a metal surface will cause the transformer to fail.

If the heater was ordered with a multiple heater control option, one thermostat can be used to control up to six heaters. The option includes a 40VA transformer that replaces the standard transformer in the “master” unit and a relay assembly that attaches to the “slave” unit. Option CL31 provides for control of two heaters. If control of additional heaters is desired (up to six total), Option CL32 which is the relay assembly only must be added to each of the “slave” heaters.

The option packages are shipped separately and include complete instructions on installation and wiring.

The combustion air proving switch is a pressure sensitive switch that monitors air pressure to ensure that proper combustion airflow is available. On Model UDAP, the switch is a single pole/normally open device which closes when a negative pressure is sensed in the venter housing. On Model UDAS, the switch senses the differential pressure between the negative pressure in the venter housing and the pressure in the cabinet. (For switch location, see FIGURE 18, page 31.)

On startup when the heater is cold, the sensing pressure is at the most negative level, and as the heater and flue system warm up, the sensing pressure becomes less negative. After the system has reached equilibrium (about 20 minutes), the sensing pressure levels off.

If a restriction or excessive flue length or turns cause the sensing pressure to be outside the switch setpoint, the pressure switch will function to shutoff the main burner. The main burner will remain off until the system has cooled and/or the flue system resistance is reduced.

Form RZ-NA I-UDA, Mfg #195673 Rev 5, Page 17

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Contents Series Fan-Type Unit Heaters Table of ContentsGeneral Installation CodesHazard Levels of Warnings in this Manual Venting Manual by ModelMassachusetts Requirement Warranty Uncrating and PreparationSize DimensionsModel Udas Separated Combustion Fan Size 100 125 Technical DataPressure Switch Instructions for Changing Pressure SwitchHigh Altitude Operation ClearancesModel Udap and Model UDAP-CV Combustion Air applies to Model Udap and ModelLocation Recommendations Unit Heater LocationHeater Throw Hanging the Heater Unit Heater Location cont’dModel Udap Size 100 125 150 175 225 250 300 350 400 Model Udas Size 100 125 150 175 225 250 300 350 400Recommended maximum hanger rod length is 6 feet 1.8M Connectors areBe sure Threaded swivel Locked toGas Connection Size Gas Piping and PressuresSizing Gas Supply Line Instructions Gas Piping and Pressures cont’d Manifold Pressure Settings by Altitude for CanadaInstructions for High Altitude Derate Two -Stage ValveFeet Meters High Altitude Capacity ChangesThermostat and Connections Burner Electrical Supply and ConnectionsCombustion Air Proving Switch Pressure Switch Limit Control Pressure Switch SettingsCombustion Air Proving Dip Switch Door Switch Model Udas only Ignition SystemNormal Heat Cycle Operating Sequence StatusLED LightsSW1 SW2 Time Ignition System cont’dContinuous Fan Operation Fault Modes Gas Valve Fan Motor Fault Modes cont’d LockoutOperating Sequence Wiring DiagramsWiring Diagrams cont’d SW1 Operating Instructions Operating Sequence Check Installation and StartupCheck the installation prior to startup Heater Startup Vent System Testing Procedure Model Udap Check installation after startupUse only factory-authorized parts Maintenance ScheduleStartup cont’d Burner Removal Instructions Refer to Figure Heat Exchanger Maintenance Burner MaintenanceInspect and Clean the Burner Re-Install the Burner Burner Maintenance cont’dInstructions to Re-Install the Burner Refer to Figure Burner OrificeDSI System IgnitionCont’d Fan BladesDoor Switch Combustion Air Pressure SwitchOperating Gas Valve Udas onlySwitch Flame Rollout Switch Sizes 30-125 onlyAir System Troubleshooting DisconnectVenter motor General TroubleshootingWill not start Burner willCont’d Troubleshooting cont’d

UDAP, UDAS specifications

Thomas & Betts is a well-respected name in the electrical and industrial products sector, known for its innovation and quality. Among its impressive portfolio, the UDAS and UDAP series of connectors stand out for their reliable performance and advanced features. These connectors are specifically designed to meet the rigorous demands of electrical applications in various industries.

The UDAS (Universal Disconnect Appliance Switch) and UDAP (Universal Disconnect Appliance Plug) are engineered for high-capacity applications where safety, efficiency, and ease of use are paramount. One of the main features of these connectors is their ability to deliver increased electrical resistance and durability. They are constructed from high-quality materials that can withstand extreme environmental conditions, making them ideal for outdoor and harsh industrial applications.

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The UDAS and UDAP connectors are manufactured to comply with several industry standards, ensuring that they meet or exceed the requirements for electrical safety and performance. Their user-centric design features help in reducing installation time and costs, making them a preferred choice among contractors and engineers.

Furthermore, these connectors are versatile, compatible with a wide range of electrical systems, and can be employed in applications such as HVAC, lighting, and power distribution. They also come in various sizes and configurations to accommodate diverse specifications, improving customization options for different projects.

In summary, the Thomas & Betts UDAS and UDAP series stands out for their robust design, quick-connect technology, and versatility across various industrial applications. Their durability and compliance with safety standards make them an excellent choice for professionals seeking reliable connectivity solutions in demanding environments. Investing in these connectors ensures optimal performance and safety in electrical installations, showcasing Thomas & Betts' commitment to excellence in electrical components.
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