Brand: K-Rain SKU: 1521
Product Overview
The K-Rain 1521 is a pump start relay that allows a compatible controller or timer with a 120 VAC control output to start and stop an irrigation pump without routing the pump's full motor current through the controller. The relay uses a 120 VAC coil and switches an approved pump load through double-pole, single-throw contacts.
K-Rain rates the 1521 for compatible pump loads up to 3 horsepower at either 120 VAC or 240 VAC. The control-coil voltage and motor-load voltage are separate specifications: the coil must receive the correct 120 VAC control signal, while the relay contacts switch the pump supply circuit. This distinction is critical because the 1521 is not the correct model for a typical 24 VAC master-valve or pump-start output.
The relay is housed in a rainproof Type 3R enclosure with accessible terminals and conduit entry locations. Before ordering, confirm the controller's pump-start output voltage, pump phase, supply voltage, horsepower, full-load current, starting current, wire size, disconnecting means, and required overcurrent protection. Installation involves hazardous line voltage and should be completed by a qualified electrician or irrigation professional following the current K-Rain instructions and applicable codes.
Key Features
- 120 VAC, 60 Hz control coil
- Double-pole, single-throw relay contacts
- Compatible load rating up to 3 HP at 120 or 240 VAC
- 20-amp inductive and 30-amp resistive contact ratings
- Rainproof Type 3R enclosure
- Large wiring-access area with recessed knockouts
Common Uses
- Starting a compatible irrigation pump from a 120V timer output
- Separating controller current from motor current
- Replacing an exact K-Rain 1521 relay assembly
Compatibility and Installation Notes
- The controller signal must match the 120 VAC coil.
- Do not connect this coil to a standard 24 VAC pump-start terminal.
- Confirm motor horsepower and current remain within all relay ratings.
- This model uses double-pole contacts and is not intended for three-phase pump switching.
- Disconnect all power sources before installation or service.
Frequently Asked Questions
Can a standard 24V irrigation controller activate the 1521?
No. The 1521 has a 120 VAC coil. Use a verified 24 VAC-coil relay when the controller provides a standard 24 VAC pump-start signal.
Does the relay supply power to the pump?
No. It switches a separately supplied pump circuit when the control coil is energized.
Can it control a three-phase pump?
No. The 1521 uses double-pole, single-throw contacts. Use a verified three-phase relay configuration when required.
Why Buy This K-Rain 1521 from Big Frog Supply?
Big Frog Supply clearly separates the 1521's 120V coil from the pump circuit rating, helping prevent the common mistake of ordering it for a 24V controller output or confusing it with the otherwise similar 1522.
Product Type Pump start relay
Manufacturer Part Number 1521
Control Coil 120 VAC, 60 Hz
Contact Configuration Double pole, single throw
Pump Load Rating Up to 3 HP at 120 VAC; up to 3 HP at 240 VAC
Inductive Contact Rating 20 A
Resistive Contact Rating 30 A
Coil Inrush 42 VA per current product specification brochure
Coil Sealed 8.5 VA, 3.6 W per current product specification brochure
Enclosure Type 3R rainproof
Three-Phase Operation No
