The OSO Immersion Heater with Pocket (current product code 72091) is a genuine OSO Hotwater replacement element rated 3kW at 240V, supplied without a built-in thermostat. Instead, it is fitted with a thermostat pocket, designed for use with a separate rod or smart thermostat fitted into the pocket after installation.
This variant is specifically intended for the OSO SX-IQ cylinder range. It is the current replacement for the earlier OSO code 71248, and supersedes the now-discontinued interim code 71252. It shares the same 1-1/4" non-standard OSO boss as the standard built-in-thermostat heater, so the same 50mm box spanner is required for installation.
1-1/4"
Boss Size (Non-Standard)
Rod or Smart
Thermostat Compatibility
SX-IQ
Primary Cylinder Compatibility
Please Note: This heater does not include a thermostat. It is supplied with a thermostat pocket only, and a separate rod or smart thermostat must be fitted into the pocket to complete the installation. Confirm which thermostat your OSO SX-IQ cylinder requires before ordering.
Good to Know: OSO Product Code 72091 is the current listing for this part on the manufacturer's own spares site. The interim code 71252, which previously covered this same specification, has since been discontinued.
Thermostat Pocket for Rod or Smart Thermostats
Rather than a built-in thermostat, this element has a dedicated pocket allowing either a conventional rod thermostat or a compatible smart thermostat to be fitted, giving flexibility over temperature control method.
Purpose-Built for OSO SX-IQ Cylinders
This part is specifically designed and listed as compatible with the OSO SX-IQ cylinder range, distinguishing it from the standard built-in-thermostat element used across other OSO series.
Direct Replacement for Code 71248
This part directly replaces OSO code 71248, making it the current specification for like-for-like replacement on SX-IQ cylinders originally fitted with that earlier element. It also supersedes the discontinued interim code 71252.
Same Non-Standard 1-1/4" Boss
Uses the same 1-1/4" non-standard OSO boss as the rest of the OSO immersion heater range, requiring a 50mm box spanner for installation or removal.
3kW Output at 240V
Rated at 3kW, 240V, matching the power output of OSO's standard built-in-thermostat immersion heater, so heat-up performance is unaffected by the choice of pocket-mounted thermostat.
| General Specification |
| Manufacturer |
OSO Hotwater (UK) Limited |
| OSO Product Code |
72091 |
| Replaces |
71248 (also supersedes discontinued interim code 71252) |
| Power Rating |
3kW @ 240V |
| Boss Size |
1-1/4" (non-standard OSO boss) |
| Thermostat Type |
Pocket only — for separate rod or smart thermostat (not included) |
| Recommended Tool |
50mm box spanner |
| Electrical Connection |
Double-pole linked switch, minimum break capacity 13A |
| Cylinder Compatibility |
| Primary Compatibility |
OSO SX-IQ |
Important Safety Information: This is a mains-voltage electrical heating product for installation into a water-filled cylinder. Installation, wiring and testing must be carried out by a suitably qualified electrician or a Part P registered competent person, in accordance with current IEE wiring regulations (BS 7671). The appliance must be permanently connected to the electrical supply through a double-pole linked switch with a minimum break capacity of 13A. As this heater has no built-in thermostat, a suitable rod or smart thermostat must be fitted into the pocket before the heater is energised. The heater must never be switched on unless fully immersed in water.
Does this immersion heater include a thermostat?
No. This variant (71252) is supplied with a thermostat pocket only. A separate rod or smart thermostat must be fitted into the pocket to control water temperature and provide safety cut-out protection.
What is the difference between this and the standard OSO immersion heater (8015192)?
The standard heater (8015192) has a built-in thermostat factory-fitted inside the element. This variant (72091) instead has an empty pocket, designed so a rod or smart thermostat can be fitted separately — typically to enable smart/WiFi temperature control on an OSO SX-IQ cylinder.
Which OSO cylinder is this designed for?
This part is specifically listed as compatible with the OSO SX-IQ cylinder range.
What size spanner do I need to fit this heater?
Like other OSO immersion heaters, this uses a non-standard 1-1/4" boss, and a 50mm box spanner is recommended for installation and removal.
Is this a direct replacement for an older OSO part?
Yes — this part (72091) directly replaces OSO code 71248, and also supersedes the discontinued interim code 71252.
