The Tesla UK 14" Incoloy Unvented Immersion Heater (MPN TIH476PI) is a 3kW, 240V element purpose-built for unvented hot water cylinders, using the 1-3/4" BSP boss common to sealed unvented systems rather than the standard 2-1/4" domestic boss. It is supplied complete with a thermostat and an O-ring seal, ready to fit.
Manufactured in Incoloy, this heater is recommended for medium-to-hard water areas and is suitable for use in both standard unvented cylinders and stainless steel unvented cylinders. It is approved to EN 60335-2-73, BEAB approved, and CE marked.
EN 60335-2-73
Approval Standard
Please Note: This heater uses the 1-3/4" BSP unvented boss, not the more common 2-1/4" domestic boss. Confirm your cylinder's existing thread size before ordering, as the two boss sizes are not interchangeable without a separate adaptor.
Incoloy Element for Medium-to-Hard Water
Incoloy is the manufacturer-recommended material for medium-to-hard water areas, offering improved scale resistance over a plain copper element for longer service life.
Supplied Complete with Thermostat
This heater is supplied complete with a thermostat and a WRAS-approved O-ring seal, so no separate thermostat needs to be sourced for installation.
Suitable for Stainless Steel Unvented Cylinders
Designed to be suitable for use in unvented stainless steel cylinders as well as standard unvented cylinders, without the galvanic corrosion risk associated with copper-pocket elements.
BEAB Approved & CE Marked
Manufactured to EN 60335-2-73 and BEAB approved, with full CE marking, confirming compliance with UK and European electrical safety standards.
1-3/4" Boss for Sealed Unvented Systems
Uses the 1-3/4" BSP boss specified for many sealed unvented cylinder systems, distinct from the standard 2-1/4" domestic boss used elsewhere in the Tesla range.
Horizontal Mounting
At 14" (355mm) in length, this heater is designed for horizontal fitting, in line with Tesla's general guidance that heaters of 14" or shorter mount horizontally.
| General Specification |
| Manufacturer |
Tesla UK Ltd, Sutton Coldfield, West Midlands |
| MPN |
TIH476PI |
| Element Length |
14" |
| Element Material |
Incoloy |
| Boss Size |
1-3/4" BSP |
| Power Rating |
3kW @ 240V |
| Cylinder Type |
Unvented, including stainless steel unvented cylinders |
| Approval Standard |
EN 60335-2-73 (BS EN 60335-2-73) |
| Safety Certification |
BEAB Approved |
| Other Certification |
CE Marked |
| Sealing |
O-ring, included |
| Recommended Water Hardness |
Medium to hard water areas |
| Mounting Orientation |
Horizontal |
| Warranty |
1 year manufacturer guarantee |
Important Safety Information: This is a mains-voltage electrical heating product for installation into a water-filled cylinder. It is a legal requirement under Part P of the Building Regulations that this unit is fitted by a competent, suitably qualified person, with the installation compliant with all local and national rules and current IEE wiring regulations (BS 7671). The appliance must be earthed and wired through a double-pole isolator with a contact separation of at least 3mm in all poles. The heater must never be switched on unless fully immersed in water.
What water hardness is this heater suitable for?
This Incoloy element is recommended by the manufacturer for medium-to-hard water areas. For hard-to-very-hard water, a Titanium element would offer longer service life.
Can this be used in a stainless steel cylinder?
Yes — this heater is specifically suitable for use in unvented stainless steel cylinders, as well as standard unvented cylinders.
Does this heater include a thermostat?
Yes, it is supplied complete with a thermostat and a WRAS-approved O-ring seal, ready to install.
What boss size does this heater use?
This variant uses a 1-3/4" BSP boss, which is specified for many sealed unvented cylinder systems, rather than the more common 2-1/4" domestic boss.
Should this be fitted horizontally or vertically?
At 14" in length, this heater is designed for horizontal fitting, following Tesla's general guidance that heaters 14" (355mm) or shorter mount horizontally.
What approvals does this heater carry?
It is manufactured to EN 60335-2-73, is BEAB approved, and carries full CE marking, confirming compliance with UK and European electrical safety requirements.
