© 2018 tekmar 304P_D - 12/18
304P_D
12/18
Zoning
Replaces: 11/16
Switching Relay 304P
Installation & Operation Manual
• RoomResponse
TM
signal
• Compatible with all low voltage thermostats
• Unlimited zone expansion
• Zone priority
• Priority override
• Pump exercising
• Post purge
• LED for each zone, priority, end switch and RoomResponse
TM
• Away signal shared between tekmar thermostats
• Four ground screws
• Top, bottom and back conduit knockouts
• Fuses protect transformers and pumps
• Two spare fuses included
• CSA approved
Introduction
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 RoomResponse
TM
signal to modulating-condensing boilers to optimize comfort while improving boiler efficiency.
RoomResponse
TM
Power
Priority
Zone 1
Zone 2
Zone 3
Zone 4
Switching Relay 304P
Four Zones with Priority
H3020A
Features