Description
The Tekmar 303P is a three‑zone switching relay designed for hydronic heating systems. It accepts up to three low‑voltage (24 V) thermostats and controls up to three circulators. Zone 1 has optional priority over zones 2 and 3, which makes it ideal for configurations with an indirect domestic hot water load. The control also provides a RoomResponse™ output signal for modulating‑condensing boilers to optimize comfort and efficiency.
Features
- Supports up to three thermostats and three pumps
- Priority override on Zone 1 for indirect domestic hot water applications
- Pump exercising to prevent circulator seizure when idle
- Post‑purge of last operating zone to increase energy savings
- RoomResponse™ signal output compatible with modulating‑condensing boilers
- LED indicators for each zone, priority status, end‑switch and RoomResponse™
- Top, bottom and back conduit knockouts for flexible wiring
- Fuses protect transformer and pump circuits; two spare fuses included
- CSA C / US listed, indoor use only
Specs
| Agency Approvals | CSA C US |
| Ambient Conditions | Indoor use only, 32 to 122 degrees F (0 to 50 degrees C), RH less than or equal to 90 percent non-condensing |
| Control Load | 7 VA |
| Control Type | Microprocessor control, is not a safety/limit control |
| Dimensions | 8-3/16" H x 10-11/16" W x 2-3/8" D (208 x 271 x 60 mm) |
| Enclosure Material | ABS Plastic, Glavanized Steel |
| Enclosure NEMA Rating | NEMA 1 |
| Markets | Multifamily Homes, Single-Family Homes, Small Commercial Buildings |
| Power Supply | 115 V (ac) plus / minus 10 percent, 60 Hz, 11 A |
| Pump Relay | 115 V (ac), 5 A, 1/3 hp, 17.3 A combined |
