Low surface temperature fan convectors for buildings with vulnerable people
Active LST Fan Convectors are Belgravia Classic and Belgravia Supreme Fan Convectors fitted with SPC’s Active LST (low surface temperature) control. A thermal switch on the outlet grille, the hottest point of the casing, closes a valve at the coil connection to keep the casing surface at or below 43°C, the figure NHS guidelines give for vulnerable occupants. Active LST is available on the floor-standing A and BS styles in all four sizes.
Manufactured in Leicester by S & P Coil Products Limited, Active LST Fan Convectors are specified for hospitals, care homes, special schools, nurseries and other buildings where someone could fall against the heating and be unable to move away. Surface temperature and heating capacity are controlled separately, so the usual Belgravia thermostats, switches and BMS options still control the heat.
43°C limit
Casing held at or below the NHS guideline figure
Direct sensing
Measures the casing at its hottest point
Classic or Supreme
A and BS floor-standing styles in four sizes
Made in Leicester
Designed, tested and built by SPC
43°C
Maximum casing surface temperature: the figure NHS guidelines give for vulnerable occupants.
Tested at 85/75°C
SPC testing held a Belgravia Classic A style unit at 43°C with 85/75°C flow and return water, the worst case for a conventional boiler.
Up to 8.0 kW
Heating output from a BEL/SPR150 unit with Active LST, with 80/60°C water and 20°C room air.
4 sizes
Nominal lengths from 700 to 1,500 mm (Belgravia Classic) and 800 to 1,600 mm (Belgravia Supreme).
What are Active LST Fan Convectors?
Active LST Fan Convectors are LTHW fan convectors with a surface temperature limit built in. Fan convector casings usually run at around 50 to 55°C, because the coil heat exchanger made by SPC is shrouded inside the casing. Where vulnerable people could fall against the heating, that is not always low enough, so Active LST measures the casing directly and limits it to 43°C. For the whole range, see Belgravia Fan Convectors.
Because Active LST responds to the measured surface temperature, not to the air or water temperature, it holds the same 43°C maximum whatever the water and air conditions. When the casing nears the limit, the actuator closes the valve over about three minutes, and as the casing cools the valve opens again. The chart shows the outlet grille temperature of an SPC fan convector with Active LST control.
Measured outlet grille temperature (°C) over 16 minutes on an SPC fan convector with Active LST control
What sizes do Active LST Fan Convectors come in?
Active LST Fan Convectors come in all four Belgravia Classic and Belgravia Supreme sizes, in the floor-standing A and BS styles, with standard 2-row coils.
| Size | Belgravia Classic nominal length (mm) | Belgravia Supreme nominal length (mm) |
|---|---|---|
| 40 | 700 | 800 |
| 60 | 900 | 1,000 |
| 90 | 1,200 | 1,300 |
| 150 | 1,500 | 1,600 |
Planning heating for a school? Read our guides: Specifying Fan Convectors for Schools: What to Choose for a Half-Term or Holiday Window and Why Do Schools Use Fan Convectors and Radiant Panels Together in a Heating Upgrade?
How does Active LST control work?
Active LST senses the casing at its hottest point and closes a valve to reduce the hot water flow when the surface nears 43°C.
- Thermal switch on the outlet grille, where SPC testing measured the highest casing temperatures
- 230 V thermic actuator, on/off, closing in about three minutes with a maximum draw of 2 W
- The valve opens again as the casing cools, so the unit carries on heating
Who needs low surface temperature heating?
NHS guidelines give 43°C as the maximum exposed surface temperature where unsupervised vulnerable people could fall against a heater.
- Hospitals, care homes and supported living
- Special schools, nurseries and early years settings
- Any room where occupants may be left unsupervised near the heating
Does Active LST reduce heat output?
Active LST limits the surface temperature, not the heating capacity, which is still set by the fan speed and controls.
- With 80/60°C water and 20°C room air, outputs run from 3.1 kW (BEL/SPR40) to 8.0 kW (BEL/SPR150)
- The valve only closes when the casing nears 43°C, so average output depends on the water and air conditions
- Fan speed and room temperature are controlled as on any Belgravia unit
Outputs and airflows for every size are in the Active LST leaflet.
Active LST Fan Convector casing styles, controls and installation
Active LST is available on Belgravia Classic and Belgravia Supreme Fan Convectors in the vertical A and BS styles, for floor-standing units. Choose the Belgravia Supreme for a rounded casing with no sharp corners, for enhanced safety where people move close to the heating.
A and BS styles
Vertical, floor standing.
Rounded casing
Belgravia Supreme: no sharp corners.
Active LST works alongside the Belgravia capacity controls, because surface temperature and heating capacity are controlled separately.
- ALTC adjustable low water temperature fan cut-out
- In-built and remote on/off thermostats (T1, RT1) and a tamper-proof on/off thermostat (TLX1)
- Rocker switches for on/off and summer/winter (RS1, RS2, RS12)
- BMS relay for remote enable/disable (BMS1)
- Master and slave units, so one unit can control others
The thermal switch is fitted in the factory. The valve and actuator are supplied loose for your installer to fit at the coil connection, with ¾” connections, and the actuator’s two-wire 1 m cable is pre-wired to the fan convector. No additional pipework or wiring is needed.
- Air filter behind the inlet grille (AF2)
- Lockable or tamper-proof access panel (LAP, TAP)
- Plinth (P), fuse spur box (FSB) and customer connection box (CCB)
- Special paint finish to order (SPF)
Installation steps are in the Active LST installation, operation and maintenance instructions (IOM 96) in the downloads.
Active LST valve and thermic actuator, supplied loose for fitting at the coil connection
Project support from SPC: from survey to commissioning
SPC manufactures and supplies Active LST Fan Convectors for installation by your M&E contractor, and supports the project from the first survey to handover.
Site surveys
We visit site to check mounting positions and which casing styles suit each room.
Selection
We size each unit and choose the coil for your water temperatures.
Technical support
Our technical team answers coil, control and installation questions.
Area Sales Managers
A local ASM supports you from specification to delivery.
Specifying Active LST Fan Convectors
Free tools to select units and add them to your BIM model.
Select units online
Size and configure Belgravia Classic and Belgravia Supreme Fan Convectors with the Active LST option using our free online configurator, which also covers our other fan convectors, air curtains and unit heaters.
Download BIM objects
Add Belgravia Classic and Belgravia Supreme Fan Convectors to your BIM model. Our BIM objects are free to download from SPC on bimstore, alongside the rest of the SPC range.
Belgravia Fan Convectors in UK projects
Active LST is an option on Belgravia Classic and Belgravia Supreme Fan Convectors, which are installed in buildings across the UK, including schools, libraries, churches and other public buildings. Recent Belgravia projects include Bickleigh Down C of E Primary School in Plymouth, Witney Library, Dover Town Hall and St George’s Church in Marlborough. See more in our Belgravia Fan Convector projects.
Active LST Fan Convector specification summary
| Feature | Active LST Fan Convectors |
|---|---|
| Available on | Belgravia Classic and Belgravia Supreme Fan Convectors |
| Casing styles | Vertical A and BS styles, floor standing |
| Sizes | 40, 60, 90 and 150 |
| Nominal lengths | Belgravia Classic 700 to 1,500 mm; Belgravia Supreme 800 to 1,600 mm |
| Coil | Standard 2-row coil heat exchanger made by SPC |
| Maximum casing surface temperature | 43°C, the NHS guideline figure for vulnerable occupants |
| Sensing | Thermal switch on the outlet grille (the hottest point), fitted in the factory |
| Valve and actuator | On/off valve with 230 V thermic actuator, closing in about 3 minutes, maximum 2 W; supplied loose for fitting at the coil connection |
| Pipe connections | ¾” connections on the unit tails |
| Wiring | Two-wire actuator with 1 m cable, pre-wired to the fan convector |
| Heating output | 3.1 to 8.0 kW (BEL/SPR40 to BEL/SPR150, 80/60°C water, 20°C room air) |
| Controls | ALTC, T1, RT1, TLX1, rocker switches (RS1, RS2, RS12), BMS1 relay, master and slave units |
| Testing | Held at 43°C with 85/75°C flow and return water (SPC test report, Belgravia Classic A style) |
| Maintenance | Active LST kit is maintenance free (IOM 96) |
| Manufactured | Leicester, UK, by S & P Coil Products Limited (ISO 9001:2015) |
Discuss your fan convector project
Planning heating for a hospital, care home, special school, nursery or other building where vulnerable people are close to the heating? Tell us about your project and we will help you specify Active LST Fan Convectors. Call 0116 249 0044 or email spc@spc-hvac.co.uk.
Frequently Asked Questions
An LST fan convector keeps the surfaces people can touch at or below a set temperature, usually 43°C, so that someone who falls against it is not burned. Active LST Fan Convectors do this by measuring the casing temperature at its hottest point and reducing the hot water flow, so the limit holds even with high water temperatures.
NHS guidelines give 43°C as the maximum exposed surface temperature where unsupervised vulnerable people could fall against a heat emitter or its pipework. Active LST Fan Convectors keep the casing at or below this figure. Check which guidance applies to your project with the client or designer.
Active LST is available on Belgravia Classic and Belgravia Supreme Fan Convectors in the vertical A and BS styles, for floor-standing units, in all four sizes with standard 2-row coils. It is not offered on ceiling-mounted units or on Belgravia Tilevector Fan Convectors.
No. The thermal switch is fitted in the factory. The valve and actuator are supplied loose: the installer screws the valve into the coil connection, and the actuator clips onto the valve. The actuator’s two-wire 1 m cable is already wired to the fan convector, so no additional pipework or wiring is needed. IOM 96 in the downloads below has the steps.
Yes. Active LST can be supplied as a retrofit kit for existing Belgravia Classic and Belgravia Supreme Fan Convectors. The kit includes the thermal switch, valve and actuator. Contact SPC with your unit details to confirm compatibility before ordering.
Active LST controls the surface temperature, not the heating capacity. The valve only closes when the casing nears 43°C and opens again as the casing cools, so the average output over time depends on the water and air conditions. Fan speed and room temperature are still controlled by the unit’s thermostats, switches or BMS.
Active LST is available with standard 2-row coils and is intended for units fed with higher water temperatures, such as conventional boiler systems, where the casing could otherwise go above 43°C. For a heat pump or other low water temperature system, talk to SPC about the right Belgravia coil and whether Active LST is needed.
The Active LST kit is maintenance free; general maintenance follows the fan convector’s own instructions. Faults specific to Active LST are limited to the valve not opening or closing, so check the wiring against the wiring diagram before replacing any parts.
Yes, in practice. LTHW (low temperature hot water) and LPHW (low pressure hot water) both describe the wet heating systems Belgravia Fan Convectors run on. SPC uses LTHW.
