Frequently Asked Questions
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Can the FHT Stove be connected to a 'Combi' central heating system? Up Arrow

Yes!   FHT Stove components are designed for operation with pressurised central heating systems as required for 'Combi' boilers. Stove heat can circulate in the heating system to supply radiators but cannot heat the hot water as this requires the short-term high output of the boiler for 'instant' heating.

How many radiators can an FHT Stove supply? Up Arrow

Around half of the stove output can be sent to the central heating system. For a nominal 5kW stove (range 3~7kW) typically 2~3kW of heat is transferred to the heating system when the fan is 'on'. This is not enough to heat the whole house, but would provide all the heat for a moderate sized adjacent room.

When used with a central heating system, the heat gets dispersed throughout the house, so this either gently warms the rooms away from the stove, or reduces the amount of fuel used by the central heating boiler when operated in parallel.

In terms of radiator sizing, one typical radiator, 600mm tall, 1200mm wide, single panel, will output around 1,200W at 75°C water temperature, so 2~3 radiators can be supplied.

Is the FHT Stove noisy? Up Arrow

The FHT Stove incorporates a small electric fan to direct air heated by the stove surfaces towards a heat exchanger. The fan is optimised to be quieter than most refrigerators and consumes only around 10W of power - about the same as an energy efficient light bulb.

Are there any restrictions to the location of radiators connected to the FHT Stove? Up Arrow

No! The FHT Stove utilises a low power pumped circuit where hot water can be sent to radiators in any location, even on floors below the room in which the stove is located. There is no need for wide bore pipes for 'natural circulation' as required for most 'back boiler' stoves.

When the FHT Stove is connected to an existing central heating system, stove heat is distributed throughout the home via the heating system, supplying any radiator that is turned on and working in parallel with the central heating boiler if it is operating.

Do I need big pipes to connect the FHT Stove? Up Arrow

No!   The FHT Stove can be connected in any preferred pipe bore provided sufficient flow can be achieved. Connection via small bore piping allows neat, hidden pipe-work to be used so that the appearance of your installation is not affected.

Can the FHT Stove be connected to pressurised central heating systems? Up Arrow

Yes!   FHT Stove components are designed for operation in excess of 3Bar in line with requirements for pressurised heating systems (with an expansion vessel). The FHT Stove can also be connected to open vented systems if required. See also 'Combi' answer above.

What happens in the event of a power supply failure? Up Arrow

The FHT Stove simply reverts to 'off' mode and all the stove heat is released into the room in which the stove is located. The design is fail-safe and cannot result in the central heating water boiling in the stove.

TRV Can I have TRVs on my radiators? Up Arrow

Yes! This is a unique feature of the FHT Stove. Whether the stove is sending heat to the central heating system or a dedicated radiator loop, the radiators can be turned 'on' and 'off', or can be controlled by thermostatic valves. The FHT Stove incorporates simple controls that detect whether there is sufficient heat demand elsewhere to distribute heat, and if necessary it can turn off if the water becomes too hot.

What happens if the radiators are turned off? Up Arrow

See answer above - if there is not a heat demand the FHT Stove simply reverts to sending all the heat to the room as hot air.

How does the FHT Stove compare to back boiler systems with safety cold water loops? Up Arrow

A number of stove manufacturers are now offering back boiler systems which incorporate a safety feature which dumps cold water through the back boiler to prevent boiling if the water overheats. Whereas such technology is clearly an important safety advance over a simple back boiler system, it only offers emergency protection to the customer. The FHT Stove offers fail-safe operation which does not rely on additional cold water 'dump' circuits (and the plumbing costs associated), but also offers the considerable benefit of giving the user the ability to choose whether to transfer heat or to send all the heat to the room.

Is the FHT Stove a replacement for back boilers? Up Arrow

No - although it does offer considerably lower installed costs for customers who specifically want a 'back boiler' system. Typically, 'back boiler' stoves transfer a higher proportion of the fire heat to a radiator circuit whenever the stove is lit with no on/off control.

The FHT Stove is aimed at all stove users, primarily to give additional comfort control, improved efficiency, and a reduced Carbon 'footprint'. As the FHT Stove can be turned 'on' and 'off', customers can choose to have all the heat passing to the room, or if it becomes too warm, to direct around half of the heat to other locations via the existing central heating system or a dedicated radiator loop.

Stove flames
Can FHT Stoves be used in Smoke Controlled Regions? Up Arrow

Yes! The FHT Stove will only be implemented on the most efficient convector stoves. Stoves which meet the 'clean burn' requirements for DEFRA smoke controlled area exempt appliances and those which are Ecodesign Ready (ready for new, tighter efficiency and emissions requirements in 2022) maintain a high fire temperature which can be maintained by the FHT Stove. Most 'back boiler' stoves are unlikely to achieve these standards as the boiler surrounds the fire and cools combustion. The FHT Stove is therefore 'future proof'!

To achieve high efficiency and low emissions, stoves often require that the fire cannot be 'damped' down as a smouldering fire is inefficient and emits a lot of smoke (particulates). The benefit of the FHT Stove under these circumstances is that heat output to the room can be reduced by turning 'on' the heat transfer whilst still burning efficiently and cleanly.

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