Heyco

Heyco sensor mounts for pool temperature measurement

Temperature measurement sits behind almost every automated function in a pool installation. A controller only switches a heat pump, a boiler circuit, a solar loop or a frost protection routine once it knows how warm the water actually is, and that reading comes from a sensor sitting in the flow. The sensor itself needs somewhere to live, and that is the job of a screw-in mount: a threaded fitting that holds the probe in the pipe run so the tip is in contact with the water while the cable stays dry and accessible on the outside.

Here you will find the Heyco fitting listed for this purpose, intended for temperature sensors with a 3/8″ screw thread. It is a small part, but it is the kind of component that stops an installation in its tracks when it is missing, cross-threaded or the wrong size, so it is worth identifying carefully before ordering.

The 3231 screw-in mount for 3/8″ sensors

The Heyco 3231 is a screw-in sensor mount sized for temperature sensors with a 3/8″ thread. In practice it is used where a probe has to be introduced into pipework, a manifold, a filter housing or a heater body and held securely in position. The threaded body takes the sensor; the mount is fixed into the pipe or housing so that the probe can be removed later for checking or replacement without having to break into the plumbing itself.

Because the thread size defines compatibility, the first thing to confirm is the sensor you are working with. A 3/8″ probe will not seat in a 1/2″ boss and vice versa, and forcing a mismatched thread damages both parts. If the existing sensor is still in place, read the thread marking or measure the male thread before ordering a replacement mount.

Identifying the right fitting before you order

A few checks save a return trip to the plant room:

• Taille du filetage – the 3231 is for 3/8″ sensors. Measure the outside diameter of the sensor thread, or check the sensor’s own documentation, rather than guessing from appearance.
• Sensor length and tip shape – the probe needs to reach into the water flow, not stop short in the wall of the pipe. Note how far the old sensor protruded when it was removed.
• Where the mount sits – before or after the heater, on the suction side, in a bypass, or in a dedicated boss. The position affects the reading the controller sees and should be kept the same as the original unless the equipment manual says otherwise.
• Méthode d'étanchéité – threaded fittings in pool pipework are normally sealed with PTFE tape or a suitable thread sealant. Check whether the original used a washer or an O-ring and have a replacement to hand.
• Référence du schéma éclaté – if the mount is part of a heater, controller or filtration assembly, match the position number on the manufacturer’s parts diagram. That is usually quicker and safer than comparing photographs.

Installation and maintenance notes

Work on a depressurised, drained section of pipe. Threaded sensor mounts should be tightened by hand first to make sure the thread has started straight, then brought up with a spanner on the flats rather than on the sensor body or cable gland. Over-tightening a plastic boss is one of the most common causes of hairline cracks that only show up as a slow weep days later, so firm is enough.

Once refilled, run the circulation and check around the fitting while the system is under pressure. Then compare the controller’s displayed temperature with a separate thermometer in the pool. A reading that is consistently high or low, or that swings about, often points to a probe that is not properly immersed, is sitting in a dead leg, or has a poor connection at the terminal rather than to a faulty controller.

Sensors and their mounts live in a warm, chemically treated environment, so they do age. Signs that a mount needs attention include corrosion or staining at the thread, a sensor that has become difficult to turn, or moisture tracking along the cable where it leaves the fitting.

Heyco at PoolParthub.com

Here we list the Heyco screw-in sensor mount for 3/8″ temperature sensors, article 3231, alongside the broader range of sensors, controllers and plumbing fittings used in pool heating and automation. Small threaded components like this are stocked because they are rarely held locally and are almost always needed in a hurry, during a service visit or a repair rather than a planned upgrade.

If you are unsure whether this mount matches your sensor, note the thread size, the probe length and the make and model of the equipment it belongs to, and compare those details with the parts list for your unit before ordering.