Flueboost FAQs

Why is there no live feed to the boiler?

On a new installation this usually indicates that the unit has been incorrectly wired so please read the instructions supplied carefully and ensure that the unit has a separate live supply to the fan. This allows the fan to start the pre purge process and allow the boiler/water heater to ignite once the pressure switch makes contact.

Do not put the switch live with the permanent live as this sends a continuous feed to the relays and prevents the post purge from taking place. It also damages the relays after a while which results in early failure of the pcb.

Fault Checklist

  • Check that the unit is correctly wired
  • Turn up the fan speed (350/800 models only)
  • Check for flue blockage by performing a spillage test
  • Check airflow pressure on the ports using a micro manometer
  • The pressure switch could be blocked with moisture so try cleaning the tubes
  • Blow down the positive (+)port and listen to determine that the switch is making & closing contact
  • Try adjusting the switch anti clockwise no more than one full turn
  • Check the fuses on the circuit board (350/800 models only)

Why is the motor not working?

Check fuses are ok – 5 amp maximum.
Isolate the fan supply and check if the motor can be moved freely – motor bearings may have seized.

Can a new motor be fitted?

Yes although we cannot offer a guarantee if this is not factory fitted. Our fans are designed so that the inner control tray can be removed as a sub assembly and returned to us for assessment and repair; a quotation would be supplied prior to carrying out any work.

Note: We do not offer this service for units over 5 years old. Replacement parts fitted by Flueboost carry a 12 month warranty.

Do you re-stock goods?

Yes providing the product is returned within 14 days of purchase and in the original packaging we will re-stock subject to a 20% re-stocking charge.

Low voltage boilers

The fan can be used but low voltage relays need to be installed to reduce the voltage from 240 to 12-24v then back up again.

Can the fan run permanently?

Although our fans can run for 24 hours a day we do not recommend this as it will decrease the life expectancy of the unit. The motor bearings and windings should ideally have a cooling down period to prevent them overheating and burning out. Ideally the unit should be integrated into a time clock, thermostat or BMS as shown on the instructions supplied with the fan.

How do I Install a new PCB?

NOTE: If your boiler transformer or control is faulty or broken it will blow the new board so ensure these are fully tested beforehand.

Before installation of a new board check that the fan motor is not faulty by connecting a 240v live and neutral through the incoming mains and testing that the motor starts. If it doesn't start, do not install the new PCB as a faulty motor will cause the new board to blow. Please contact Flueboost for advice.

Checklist for fitting a new PCB
After ensuring the instructions above have been adhered to take the following steps:

  • Disconnect switch live to boiler supply cable on the 350/800 models)
  • Turn on and put multi meters on the boiler live supply cable
  • Bring a neutral in from the incoming mains to determine that there is a 240v supply out after the 30-50 second pre-purge has elapsed
  • Turn off then reconnect the switch live feed back to the boiler
  • Check boiler/gas valve isn't faulty before reconnecting

How do I maintain my fan?

  • Isolate the fan supply
  • Disconnect the lead (350/800 series only)
  • Remove the inner sub assembly as shown below
  • Clean the fan blade using either a soft brush or ideally an air compressor


Do not lubricate the fan motor as it has sealed for life bearings.

NOTE: Take care not to cause imbalance when cleaning the main impeller.

Please note, do not attempt any maintenance work on any electrical appliance unless you are a fully qualified electrician.

Fan Maintenance

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