Views: 0 Author: JC Publish Time: 2026-11-10 Origin: JC
An electrically heated hose is a small engineered system: an inner tube, a uniformly braided heating layer, insulation, a temperature sensor and a cable that must match the controller on the machine. When the display shows an error, the temperature hunts, or the hose never reaches set point, the cause is often not a failed heater. It is more often a sensor the controller cannot read, a pin that does not match the drawing, or a supply voltage the hose was not built for.
This article is a practical field checklist for those faults. It follows the sensor types, voltages and wiring fields on the JINGCHENG order form, and the installation rules in the catalog. It does not replace the pin table supplied with your hose, and it is not a reason to modify the assembly.
If the hose still has its label, read the model code first. A code such as JCH-200-16-B-3X220-P2-8 already tells you the working temperature (200 °C), inner diameter (Φ16 mm), inner tube material, voltage (three-phase four-wire 220 V), sensor (PT100 two-wire) and working pressure (8 MPa). Compare the sensor letter with the controller input before replacing anything.
Sensor code | Meaning |
|---|---|
P2 | PT100, two-wire |
P3 | PT100, three-wire |
K | Type K thermocouple |
J | Type J thermocouple |
W | No sensor |
T | Special sensor |
The catalog order form also lists Ni120 and PT1000 as standard options; these are called out in the inquiry or coded as a special sensor (T). Your controller is built for one input type. A Type K hose on a PT100 channel, or a two-wire PT100 hose on a three-wire input, will typically show an open-sensor error, a frozen reading or a temperature that never makes sense.
Check three things: the sensor on the hose label, the input type in the controller manual or on its terminal diagram, and the pin table supplied with the hose. When you order a replacement, specify the same sensor as the original, including PT100 two-wire (P2) versus three-wire (P3). If the old label is missing, read the controller first and match the hose to it.
JINGCHENG heated hoses can be built with a Type J thermocouple, a Type K thermocouple, Ni120, PT100, PT1000, or another special sensor. De-energize the hose and disconnect the sensor leads from the controller before you measure resistance or continuity.
Confirm J versus K. They use different alloys and are not interchangeable. A K hose on a J input, or the reverse, can display a plausible but wrong temperature.
Check polarity at the connector and at the controller terminals. Reversed thermocouple leads often read "cold" while the jacket is warming, or move in the wrong direction when you apply a little heat near the sensor.
An open thermocouple circuit usually produces a controller alarm or a full-scale reading, not a stable process temperature. A short between the two thermoelement wires often looks like a room-temperature or near-zero reading even when the jacket is warm.
PT100 and PT1000 are platinum resistance sensors; Ni120 is a nickel resistance sensor. A controller configured for one of these will not correctly read the others.
For PT100, two-wire (P2) and three-wire (P3) are not the same wiring job. A two-wire sensor on a three-wire input leaves one terminal unused or jumped; a three-wire sensor on a two-wire input loses the lead-compensation wire. Either mistake can shift the displayed temperature or trip an error.
As a quick identity check on a disconnected sensor, a PT100 is 100 Ω at 0 °C, a PT1000 is 1,000 Ω at 0 °C, and an Ni120 is 120 Ω at 0 °C. Do not apply a tester to a live controller input.
An open circuit typically alarms as a broken sensor. A short typically reads as a very low temperature.
If the controller has more than one heating channel—JINGCHENG supplies separate heating control boxes with 2, 3 or more channels—confirm that the hose sensor is landed on the channel that is enabled, and that the set point you are watching belongs to that channel.
Every JINGCHENG electrically heated hose is built to a pin table. The order form asks for pin number, wire color and function at the controller (host) end and at the gun or tool end. A hose that heats on the bench and faults on the machine is often a pin swap or a mismatched connector.
Compare the installed connector with the pin table supplied with the hose. Check pin numbers, wire colors and functions, not only the housing.
Look for bent or recessed pins, a partially mated plug, oil or moisture in the insert, and strands pulled out of a ferrule.
Confirm that heater conductors, sensor conductors and any earth or screen are on the pins the table calls for. A sensor pair landed on heater pins will not survive first power-up; a heater pair landed on a sensor input will not heat and may damage the input.
If the original connector was cut and re-terminated in the field, treat the new termination as untrusted until it is checked against the table. A photo of the connector with its pin markings is the fastest way to get a replacement hose wired correctly.
Do not re-pin or modify the hose to "make it fit" a different controller without guidance from the manufacturer. Unauthorized modification or adjustment of the hose voids the warranty. If the instructions supplied with the hose do not cover the problem, contact our engineers rather than opening the jacket.
If the sensor reading is stable and the wiring matches the table, look at the supply and the controller next.
The hose must be built for the heating-zone output it is connected to, not merely for the plant mains. Catalog options include 380 Vac, 220 Vac, 110 Vac, 12 Vdc and other values; the model code uses 220 for 220 V and 3X220 for three-phase four-wire 220 V. The catalog operating range is 12 Vac to 380 Vac, within the limits of the hose you ordered. A 220 V hose on a 110 V output will heat slowly or never reach set point. A lower-voltage hose on a higher-voltage output is a safety fault—do not try it.
JINGCHENG temperature controllers use PID control with SSR output, or PID with thyristor output. Options include a waterproof enclosure and a volt/ammeter. If the process value looks correct but the hose never warms, check that the controller is in run mode, that any alarm lockout has been cleared, and that the SSR or thyristor output is actually driving the hose.
Rated power on the order form is 110, 150, 170 or 200 W/m, or another value agreed when the hose was specified. Power per meter affects how quickly the hose reaches set point and how well it holds temperature in a cold environment. The catalog operating environment is −40 °C to +55 °C, relative humidity not more than 85 %, and atmospheric pressure 86 kPa to 106 kPa. A hose that reaches set point only very slowly in still air may be under-powered for that ambient, or may have a damaged heating circuit. A hose that overshoots hard is more often a controller-output or tuning issue than a failed sensor.
The heating layer is made of uniformly braided heating elements, intended to keep the temperature along the inner wall as even as possible. A single cold or hot section, with a correct reading at the sensor, is more often a local mechanical problem—a kink, crushed jacket, tight bend, or a length left in a cold draught—than a "bad winding."
These installation mistakes can look like a temperature-control failure. Check the routing before you condemn the sensor or the controller:
Do not twist the hose sideways during or after installation. Lateral twisting can cause leakage, flow loss, hose damage or fire, and can also damage the heating layer or the sensor leads.
Avoid sharp bends and respect the minimum bend radius specified for your hose size. Bending the hose too tightly can damage it and cause short circuit, leakage or fire.
A long run pinned to a cold steel beam, or a loop left outside a heated enclosure, can pull heat out of the hose so the sensor never sees set point, or the controller stays at full output.
The surrounding medium should not contain gases that corrode metal or damage insulation, or conductive media, and severe mold must not be present. Moisture in a connector or a damaged jacket can create leakage currents that look like sensor noise. Special environments need a customized hose.
The hose should be operated only by authorized, trained personnel.
If the medium itself is the clue—hot-melt adhesive that chars in one section, a gas sample line that wets out (JINGCHENG gas sampling hoses are offered with heat resistance up to 230 °C), or a viscous fluid that solidifies at a low point—treat that as a process-temperature or insulation problem first. Then return to the sensor and wiring checks if the controller reading does not match what you feel on the jacket. Extruder hoses, rated up to 250 °C, follow the same electrical checks.
Work in this order, with the machine in a safe state and the hose de-energized for resistance or pin checks:
Read the hose label (model code, voltage, sensor letter) and the controller input type.
Confirm Type J, Type K, Ni120, PT100 or PT1000, and for PT100 whether the hose is two-wire or three-wire.
Check the pin table against the connector: pin numbers, wire colors and functions at both ends.
Inspect the plug, pins and strain relief for damage or contamination.
Confirm that the voltage at the hose output matches the voltage the hose was built for.
Confirm that the controller channel, set point and output (SSR or thyristor) are active.
Inspect the routing for lateral twist, tight bends, crushed jackets and obvious cold or hot spots.
If the hose still faults, do not modify it. Send JINCHEN ELECTRIC TRACING CO., LTD. the model code, the controller type, a photo of the label and a photo of the connector pin markings so an engineer can guide the next step.
Need help diagnosing a heated hose temperature fault? Send JINCHEN ELECTRIC TRACING CO., LTD. the model code, the sensor and voltage on the label, and photos of the controller terminals and the connector. Our engineers will help you match the sensor, wiring and power to the machine, and every JINGCHENG hose is inspected before packing and shipment.
