Submittal

Job __________________________
Designer ______________________
Contact _______________________
© 2019 tekmar 303P
_
C - 09/19
303P_C
Submittal
Features
• RoomResponse
TM
signal (Patent Pending)
• 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
Specifications
Switching Relay 303P Three Zones with Priority
Literature
Submittal 303P_C, Installation Manual 303P_D,
Job Record 303P_J
Packaged weight 5.0 lb. (2250 g)
Dimensions 8-3/16" H x 10-11/16" W x 2-3/8" D (208 x 271 x 60 mm)
Enclosure Cover: ABS plastic, Base: galvanized steel, NEMA type 1
Approvals CSA C US, RoHS
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, 16 A
Transformer
40 VA at 24 V (ac), expandable to 80 VA with additional
transformer M3069 (sold separately)
Control load 7 VA at 24 V (ac)
Fuses
T5A 250 V slow blow 5 x 20 mm glass fuse,
two spare fuses included
Pump relays 115 V (ac), 5 A, 1/3 hp, 15 A combined
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 Ω min load impedance
4-20 mA 1kΩ max load impedance
Warranty 3 Year Limited Warranty
The Switching Relay 303P connects up to three thermostats and operates circulators to provide heating to a zoned hydronic heating
system. Zone 1 has optional priority over zones 2 and 3 and can be used to provide heat to an indirect domestic hot water tank. The
303P 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 303P provides a RoomResponse
TM
signal to modulating-condensing boilers to optimize comfort
while improving boiler efficiency.
Switching Relay 303P
Front View Side View Inside View
8–3/16"
(208 mm)
6–7/16"
(164 mm)
10-11/16"
(271 mm)
1/2" (22 mm) knockout
∅ 3/16"
(4 mm)
2-3/8"
(60 mm)
FUSE 2
FUSE 7
FUSE 8
FUSE 3 FUSE 4 FUSE 5
FUSE 6
70 80
9060
50 100
MOD MAX %
MASTER MEMBER
OFF
OFF
OFF
4-20 mA
T-STAT 1 PRIORITY : 0N
EXERCISING : ON
POST PURGE : ON
MOD BOILER : 0-10V
RESERVED
FUSE 1
120 VAC
POWER
MOD
X X
tN4
POWER ROOM
RESPONSE
T1 T2 T3 T4 T5 T6
A
DHW C R W
BOILER T-STAT 1 T-STAT 2 T-STAT 3
PRIORITY
PUMP 1
PUMP 2 PUMP 3 PUMP 4 PUMP 5 PUMP 6
L
-
+
N L N L N L N L N L N L N
tN4
A
C R W
tN4
A
C R W
T-STAT 4
tN4
A
C R W
T-STAT 5
tN4
A
C R W
T-STAT 6 EXPANSION
tN4
A
C R W
tN4
A
B C D E
9"
(229 mm)
Switching Relay 303P
Three Zones with Priority
H3025A
Power
Priority
Zone 1Zone 2Zone 3
RoomResponse
TM