Common questions about Honeywell and Resideo fan coil thermostats, BACnet communicating thermostats, and aquastat controllers. Contact our team or call (901) 458-2000.
What is the difference between the TB6575A1000 and TB6575B1000?
Both are Honeywell SuitePRO line voltage (120/240 VAC) fan coil thermostats but they differ in pipe configuration and changeover capability. The TB6575A1000 works with both 2-pipe and 4-pipe fan coil units and supports manual or automatic heat/cool changeover. The TB6575B1000 is for 2-pipe only fan coil systems and supports seasonal or manual changeover only — no automatic changeover. If your system is 4-pipe or needs automatic changeover, use the TB6575A1000. If your system is 2-pipe with a seasonal switch from heat to cool, the TB6575B1000 may be the right fit.
Is there a TB8575B1000?
No — the TB8575B1000 does not exist. The SuitePRO 24 VAC fan coil thermostat family only has the TB8575A1000. The "B" suffix in the TB6575 line (TB6575B1000) refers to the 2-pipe-only line voltage model, but there is no equivalent "B" model in the 24 VAC TB8575 line. If you need a 24 VAC SuitePRO fan coil thermostat, the correct model is the TB8575A1000.
What is the Honeywell TP970A2004?
The Honeywell TP970A2004 is a pneumatic thermostat — it uses compressed air as the control signal rather than electricity. It is a two-pipe, single-setpoint, direct-acting pneumatic thermostat that provides proportional control of pneumatic valves and damper actuators in heating and air conditioning systems. Setpoint range is 59–90°F with an adjustable throttling range of 2–10°F (factory set at 4°F). Used in older commercial buildings — hospitals, universities, office buildings — with pneumatic HVAC control systems. Replacement kits are available for Johnson Controls, Powers, Robertshaw, Barber-Colman, and older Honeywell two-pipe pneumatic thermostats. Note: the cover is sold separately. Contact us for availability.
What is the difference between the TB6575A1000 and TB8575A1000?
Both are Honeywell SuitePRO fan coil thermostats with the same features — LCD display, 3-speed fan control (Low/Med/High/Auto), 2-pipe and 4-pipe FCU capability, and manual or automatic heat/cool changeover. The only difference is voltage: the TB6575A1000 is line voltage (120/240 VAC) and the TB8575A1000 is low voltage (24 VAC). Check your existing thermostat wiring or fan coil documentation to confirm which voltage you need before ordering.
What does the TB6575A1000 replace?
The TB6575A1000 is the direct replacement for these discontinued Honeywell models: TB6575A1016, T6051A1016, T6575D1009, T6069A4010, T6575B1003, and T6575C1001. If you have any of these models installed, the TB6575A1000 is the current replacement.
What is the difference between the TC300B-G and TC320B-G?
Both are 24 VAC Honeywell commercial BACnet thermostats for fan coil, conventional, and heat pump applications with BACnet MS/TP and Modbus RTU over RS485. The TC320B-G adds Wi-Fi/BACnet IP over 2.4 GHz and Bluetooth 5.3 for wireless BAS integration and remote control via the Honeywell Connect Me app. Choose TC300B-G for wired RS485 systems; choose TC320B-G when wireless BACnet IP or app control is needed.
What is the Honeywell TC500A-N?
The TC500A-N is an advanced commercial touchscreen thermostat with Wi-Fi/BACnet IP connectivity, built-in temperature sensor, 2 universal inputs, 2 universal I/Os, and Sylk bus terminals for sensors and accessories. Configurable via touchscreen HMI or BACnet IP, with firmware upgradeable over Wi-Fi. It is the current replacement for T7350 series thermostat applications. Available in stock at Memphis Control Center.
What is a Resideo aquastat controller?
A Resideo aquastat (formerly Honeywell) is an immersion or remote bulb temperature control used to regulate or limit water temperature in hot water heating systems. Used for high-limit control (preventing overheating), low-limit control (maintaining minimum boiler temperature), and circulator control (starting the pump at setpoint). Series breakdown: L4006 (immersion copper bulb, SPST, 100–270°F depending on model); L6006 (immersion copper bulb, SPDT, high/low limit plus circulator); L4008 (remote bulb with 5.5' or 10' capillary, SPST); L6008 (remote bulb with capillary, SPDT, circulator); L4081 (dual element, separate high and low limit setpoints in one unit).
What is the Honeywell T775 series used for?
The Honeywell T775 series are electronic temperature controllers for commercial boiler control, HVAC, and industrial process temperature management. They accept multiple temperature sensor inputs and provide relay and analog outputs for controlling boilers, pumps, valves, and dampers. Key models: T775U2006 (universal single-loop, 24/120/240 VAC), T775M2048 (dual loop), T775P2003 (boiler reset with pump output and 3 included sensors), T775M2014 (4 SPDT relays, NEMA 4X enclosure).
