Overview

The Blue Sea Systems 1821 is a high-temperature sensor for monitoring raw water exhaust temperature on a boat without drilling into the pipe. It mounts on the outside of the surface being monitored and works with Blue Sea Systems products that accept a temperature sensor, including the P12 Charger, M2 OLED, and Mini OLED meters.

Its sensing range runs from -40°F to 300°F (-40°C to 150°C), which makes it useful anywhere a standard low-temperature probe would not be enough. The sensor has an 18-inch lead for short routing runs near the monitored point, and its IP65 construction is suited to wet onboard spaces that see spray and washdown water, but not full submersion.

Key features

• Measures from -40°F to 300°F (-40°C to 150°C) for higher-heat monitoring points such as raw water exhaust
• External surface-mount setup lets you monitor exhaust temperature without drilling into the hose or pipe
• Compatible with Blue Sea Systems products that require a temperature sensor, including P12 Charger, M2 OLED, and Mini OLED meters
• IP65-rated body handles water spray and washdown conditions, but it is not a submersible sensor
• 18-inch lead helps with short, tidy cable runs in engine spaces and nearby monitoring locations
• Non-polarized leads connect in either order, which keeps wiring straightforward during installation
• Multiple mounting options, including included double-sided tape, a through-hole for a #8 screw, or a hose clamp on the outside of a pipe

Installation and setup

This sensor is meant to read temperature from the outside of the component you are watching, not from inside the fluid path. On a raw water exhaust run, it can be strapped to the outside of the pipe or hose so you can track temperature changes without opening the system.

For a fixed mount, the through-hole accepts a #8 screw. For pipe mounting, a hose clamp can be used to hold the sensor against the outside surface. The included double-sided tape is useful on a clean, dry mounting point when a clamp or screw is not the better fit.

Compatibility and fit

This is a good match for boats that already use a Blue Sea Systems charger or display with a temperature-sensor input and need a remote sensor at the engine space or another hot surface. Before ordering, check that the 18-inch lead will comfortably reach the connection point on your charger or meter, especially if the display is mounted away from the area being monitored.

Because it is a high-temperature, non-submersible sensor, it fits dry-contact surface sensing better than applications where the probe needs to sit underwater or inside a tank. That makes it especially practical for engine-room monitoring where spray, heat, and vibration are part of normal use.

What’s included

• Temperature sensor
• Double-sided tape