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The Switching Relay 304P connects up to four thermostats and operates circulators to provide heating to a zoned hydronic heating system. Zone 1 has optional priority over zones 2 through 4 and can be used to provide heat to an indirect domestic hot water tank. The 304P includes optional exercising to prevent circulator seizure when not in use, and optional post purge operation of the last operating zone to maximize energy savings. The 304P provides a RoomResponseTM signal to modulating-condensing boilers to optimize comfort while improving boiler efficiency.

  • Away signal shared between tekmar thermostats
  • CSA approved
  • Compatible with all low voltage thermostats
  • Four ground screws
  • Fuses protect transformers and pumps
  • LED for each zone, priority, end switch and RoomResponseTM
  • Post purge
  • Priority override
  • Pump exercising
  • RoomResponseTM signal
  • Top, bottom and back conduit knockouts
  • Two spare fuses included
  • Unlimited zone expansion
  • Zone priority
  • Enclosure - Cover: ABS plastic, Base: galvanized steel, NEMA type 1
  • Approvals - CSA C US
  • Ambient conditions - Indoor use only, 32 to 122°F (0 to 50°C), RH 90% non-condensing
  • Power supply - 115 V (ac) ±10%, 60 Hz, 11 A
  • Transformer - 40 VA, expandable to 80 VA with additional transformer M3069 (sold separately)
  • Fuses - T5A 250 V slow blow, two spare fuses included
  • Pump relays - 230 V (ac), 5 A, 1/3 hp
  • Boiler XX end switch - 24 V (ac), 5 A
  • DHW end switch - 24 V (ac), 5 A
  • Mod boiler output - 0-10 V (dc) 500 ohm min load impedance / 4-20 mA 1 k ohm max load impedance
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