Tekmar 254 4 stage boiler control hvac hydronics

What is for sale: Tekmar 254 4 stage boiler control hvac hydronics

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The tekmar Four Stage Boiler Control 254 is a microprocessor-based control which
regulates the supply water temperature from up to 4 boilers based on the outdoor air
temperature, and optionally, the indoor air temperature. When a Setpoint Demand
signal is present, the control will operate the boilers to regulate the supply water
temperature at a selected setpoint. The System pump is turned on whenever there is
a Setpoint Demand, or whenever there is a Heat Demand and the outdoor temperature
is cool enough to require heat in the system.
Technical Specifications Dimension (h x w x d) — 6-5/8" x 7-9/16" x 2-13/16" (170 x 193 x 72mm) Weight — 2.9 lbs (1.3 Kg) Ambient — 30 to 120°F (0 to 50°C), < 95% RH non-condensing Power supply — 24Vac ± 10%, 60Hz, 3VA class II Relay capacity — SPST, 24Vac, 10 Amps Sensors — Sensor 071, Outdoor Sensor 070. Accurate with up to 500 feet (150m) 18AWG cable Control accuracy — ± 1°F (± 0.5°C)
12 Indicator lights — Power, Heat Demand, Setpoint Demand, WWSD, Unoccupied, Minimum,Supply,Pump, Stage 1, Stage 2, Stage 3, Stage 4, Test Pump output — Isolated SPST relay contacts close when heating is required Stage 1, 2, 3 & 4 output — Isolated SPST relay contacts close to operate each stage Test button — Initiates and controls pre-programmed test run Error message display — Sensor faults are indicated by flashing light codes
Heating Curve — 0.4 to 3.6 Setpoint temperature — 110 to 230°F (43 to 110°C) Minimum Supply — Off, 80 to 170°F (Off, 27 to 77°C) Boiler Differential — 2 to 42°F (1 to 23°C) Occupied — 35 to 105°F (2 to 41°C) Unoccupied — 35 to 105°F (2 to 41°C) Stage 1, 2, 3 & 4 switches — To switch each Stage off or into operating mode Rotate switch — To allow boilers to rotate firing sequence based on hours of use Fixed lead switch — Configures Stage 1 to be first/on first off regardless of hours of use Lo/Hi fire switch — Configures stages to fire and rotate as pairs Zone Control/Sensor switch — Input from tekmar Zone Control or Indoor Sensor 074 Heat Demand switch — External 24Vac signal or permanent internal signal Setpoint Demand switch — External 24Vac signal or permanent internal signal
This control was removed during system upgrades, tested 100%.
Will include 071 & 070 sensors, a real deal for someone in the boiler/hydronics trade.