Rotork YTC Smart Valve Positioner YT3350

The YT-3350 is the stainless steel 316 member of the YT-3300 smart positioner family. Everything electrical and pneumatic inside it is the same as a YT-3300; what you are buying is the enclosure. It is 5.1 kg of solid 316 against the YT-3300’s 2 kg aluminium die-casting, and it is the one model in the range that carries no paint at all — the manufacturer’s epoxy polyester powder coating is applied to every variant except the YT-3350, because bare 316 outlasts a coated substrate in the environments this model is bought for. There is no coating to chip, chalk or lift at an edge, and no aluminium underneath it to corrode once it does.

Two practical consequences of the stainless build show up in the model code. The conduit entry is G(PF) 1/2 only, where the aluminium bodies also offer NPT 1/2 and M20 × 1.5P, and the air connection is NPT 1/4 with an NPT 1/8 gauge port — a single conduit-and-air combination rather than the five the YT-3300 offers. Check your site’s cable-gland and tubing standard against that before ordering.

How the YT-3350 differs from the rest of the family

The YT-3350 keeps the full output option list: a 4~20 mA position transmitter, a mechanical (Omron, AC 125 V 3 A / DC 30 V 2 A) or proximity (P+F, DC 8.2 V 8.2 mA) limit switch, or a transmitter and switch together. Only the YT-3350 and the YT-3300 offer limit switches; the YT-3303 and YT-3301/3302 stop at the transmitter.

• Against the YT-3300 — same options, same right-yoke mounting, same electronics. Trade 3 kg of extra weight and a restricted connection choice for a housing that will not corrode.
• Against the YT-3303 — the YT-3303 is aluminium, mounts on the left-hand yoke and has a field-adjustable variable orifice, but takes no limit switches.
• Against the YT-3301/3302 — those separate the feedback sensor from the body on a cable up to 20 m, which solves heat and vibration rather than corrosion. If your problem is a hot or shaking mounting point, that is the answer, not this one.

Note also that at 5.1 kg the YT-3350 needs the bracket and the actuator yoke to carry more than twice the load of an aluminium positioner. On small actuators, check the mounting is rated for it.

Specification

KCs certificates cover the plain unit (12-KB2BO-0402X), the unit with a dry-contact limit switch (12-KB2BO-0401X) and with a non-contact limit switch (14-KB2BO-0334X). ATEX, IECEx and NEPSI intrinsic-safety approvals and the FM and CSA ratings are common with the rest of the family, as is the SIL 2 certificate V 460.02/15.

Typical application

The YT-3350 is what we quote for coastal installations around Karachi and Port Qasim and for anywhere the positioner shares its atmosphere with the process. Three cases come up repeatedly:

Biogas and effluent plant. Digester gas carries hydrogen sulphide; combined with condensate it forms an acid film that strips paint and pits aluminium within a season. A 316 body on the gas-train control valves survives it.

Sugar mill wet ends. The lime and sulphitation station, and the milling floor generally, run wet with juice, wash water and SO₂. Positioners there are effectively in a corrosive mist all crop.

Chemical dosing and washdown areas in cement and textile plants, where equipment is hosed down on a schedule and any coating breach becomes a corrosion site.

In each case the mounting hardware matters as much as the positioner: use stainless brackets and fasteners, and where the filter regulator shares the exposure, specify the stainless YT-205 or YT-225 rather than the aluminium YT-200. If the duty needs a stainless positioner but not smart functionality or HART, the analogue YT-1050 is the cheaper 316 option.

View the product manual or the datasheet, or for more details visit the manufacturer’s website.