Cotherm Thermostat Cross-Reference: GTL Controls & Safety Limiters

Cotherm of France has built bulb-and-capillary thermostats since 1948, and its GTL family is fitted across European commercial kitchens — ovens, fryers, bain-maries and warming equipment — as well as water heating. The GTL is built to order: the type code says what the device does, and the temperature range, bulb and capillary are specified when the part is ordered. This page maps the GTL type codes our customers send us most often to their verified V.Crown equivalents, and sets out the checks that make a cross-reference safe.

How to read the original part number

A Cotherm GTL code reads as series plus function: GTLH is a control, GTLHR a manual-reset safety limiter, GTLU an automatic-reset limiter, and the UL-listed versions are GTLU (automatic reset) and GTLUR (manual reset). A trailing 3 means SPDT changeover contacts instead of SPST. The code does not carry the temperature range, the bulb size or the capillary length — those are specified when the part is ordered, so always confirm them from the rating label or the dealer listing, then verify against the tables.

GTLH / GTLH3 — single-pole control thermostats

These are adjustable liquid-filled capillary controls, 20A class at 250V, built to the customer’s range anywhere from −35 to 350°C. Every range below sits inside the AG16-K envelope, so the mapping is by function and range, not by the variant digits — the capillary and bulb are made to the original’s dimensions. One worked example: a dealer-listed GTLH preset to 155°C, 20A/250V (exparta-parts ref. 505992).

Original part	Original specification	V.Crown equivalent
Cotherm GTLH	Control · adjustable · 1-pole SPST · 20A/250V · range −35 to 350°C to order	AG16-K
Cotherm GTLH3	Control · adjustable · 1-pole SPDT changeover · 20A/250V · range −35 to 350°C to order	AG16-K
Cotherm GTLH 155°C	Control · preset 155°C · 1-pole · 20A/250V · dealer ref. 505992 (exparta-parts)	AG16-K

The AG16-K capillary thermostat is built to the same envelope — 50–400°C, 16A/20A at 110V/250V, SPST/SPDT contacts, automatic reset, 100,000-cycle mechanical life — with the capillary and bulb made to the original’s dimensions and the shaft to match the existing knob. The AG16-K heads the same control family as the compact AGO series.

GTLHR / GTLHR3 / GTLUR / GTLUR3 — safety limiters (manual reset)

These are fixed-trip safety devices: they do nothing until the control fails, then cut the circuit and stay open until a technician resets them by hand. The trip point is a property of the part ordered — and on the V.Crown side it is factory-set to the original’s value, so the number you send us is the trip point we build. The GTLUR types are the UL-listed equivalents of the GTLHR types.

Original part	Original specification	V.Crown equivalent
Cotherm GTLHR	Manual reset · fixed trip to order · 1-pole SPST · 20A/250V	AG16-S (trip point to order)
Cotherm GTLHR3	Manual reset · fixed trip to order · 1-pole SPDT changeover · 20A/250V	AG16-S (trip point to order)
Cotherm GTLUR	Manual reset · fixed trip to order · 1-pole SPST · 20A/250V · UL-listed	VL-S (trip point to order)
Cotherm GTLUR3	Manual reset · fixed trip to order · 1-pole SPDT changeover · 20A/250V · UL-listed	VL-S (trip point to order)

The AG16-S manual-reset safety limiter covers the GTLHR types — 16A/20A at 110V/250V, manual reset, standard trip points 380/400/430°C with other trip points factory-set to order. The UL-listed GTLUR types map to the VL-S (manual reset, UL E491946, SPDT). The AG16-S is TÜV certified; never substitute a manual-reset limiter for an automatic-reset one to make a cross-reference fit.

GTLU / GTLU3 — safety limiters (automatic reset)

These are fixed-trip limiters that reset themselves once the temperature falls back — a different safety behaviour from the manual-reset types above, and not interchangeable with them. Their trip point is likewise factory-set to the original’s value.

Original part	Original specification	V.Crown equivalent
Cotherm GTLU	Automatic reset · fixed trip to order · 1-pole SPST · 20A/250V · UL-listed	VL-Z (trip point to order)
Cotherm GTLU3	Automatic reset · fixed trip to order · 1-pole SPDT changeover · 20A/250V · UL-listed	VL-Z (trip point to order)

The VL-Z automatic-reset safety limiter covers the GTLU types — automatic reset, UL E491946, trip point factory-set to the original’s value. A manual-reset limiter must never be replaced with an automatic-reset one (or the reverse) to make a cross-reference fit.

Outside the scope of these tables

Cotherm also makes BBSC combi thermostats (control and safety limiter in one housing, mainly for water heaters), rod thermostats for immersion heaters, electronic controls and three-phase combistats — none of which have a mechanical V.Crown equivalent in the tables above, and the three-phase combistat type codes are not published in the sources we could verify. GTL variants ordered for ranges below 50°C, for example 30–90°C water-heating controls, fall outside the AG16-K envelope and are not listed here either. Send us the number and we confirm the match in writing; a part outside these tables is not a failed match, it is an unconfirmed one.

Cotherm® is a trademark of Cotherm SAS. HengTherm parts are replacement equivalents manufactured by Guangzhou V.Crown Thermostat Co., Ltd.; we are not affiliated with Cotherm, and part numbers are used for cross-reference identification only. Verify the equivalent against the original specification before installation.

The five checks before you order

Function and reset type — a control is adjustable and cycles; a limiter is fixed-trip. On limiters, manual reset and automatic reset are different safety behaviours, not options — GTLHR and GTLUR are manual reset, GTLU is automatic reset.
Range or trip point — the original’s range must sit inside the equivalent’s range (AG16-K 50–400°C). GTL variants ordered below 50°C do not map to the AG16-K. For limiters the trip point is factory-set to the original’s value — a near-enough temperature is not a match.
Poles and current — single-pole 20A controls switch one circuit. Check the pole count, the contact form — SPST or SPDT changeover, the trailing 3 in the GTL code — and the switching current before ordering.
Capillary length and probe — read the capillary length and probe size from the rating label — the GTL code does not encode them (capillaries run 150–3000mm, bulbs Ø3–8mm). Too short will not reach the well; the probe must seat correctly in the existing thermowell.
Mounting and head temperature — the GTL is offered with several bracket options for retrofit, and the head is rated to 120°C or 150°C depending on the variant. The replacement must fit the same bracket and panel cut-out, take the same knob, and its head must sit within its temperature rating in the mounting position.

Send us the part number you are replacing — or a photo of its rating label — and we run all five checks in writing before quoting, so the equivalent arrives as a fit, not a project.

Certification: ask for numbers, then verify them

The VL-S and VL-Z are covered by UL E491946, verifiable on UL Product iQ and listed on our certifications page; the AG16-S is TÜV certified. The AG16-K’s approvals are confirmed for the exact model before ordering. When an alternative supplier quotes a safety device, ask for the file number — not a logo — and check it before the part goes into certified equipment.

Samples and trial orders

Free samples of the AG16-K and the AG16-S are available for bench testing — you only cover the courier, and the freight is credited against your first order. Trial orders start from 200 pcs, with models mixed in one shipment, and mechanical customization (range, trip point, capillary length, bulb, dial printing) is developed free of charge. Send us the Cotherm GTL code you currently buy and we will map it.