Welcome to Vent-Axia's online FAQs service

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If you do not find the answer to your question within this FAQs section, please contact us for further assistance.

Or for further information on sizing ventilation, download our technical document.

Domestic Ventilation

Please choose from the options below to proceed.

If you do not find the answer to your question within this FAQs section, please contact us for further assistance.

I have a question about a domestic/residential fan

I have a question about my basic fan

The fan or fan and shutters do not work

It is within the warranty period

If the product as been installed in accordance to the fitting/wiring instructions and there is a supply at the fan but it does not work, then return to place of purchase for a replacement.

It is outside the warranty period

Check there is a stable supply to the fan and that the impeller is able to spin freely and there is no blockage within the fan and any duct run or termination.

Check nothing is obstructing the shutters mechanism

How do I clean my fan

The product instructions will normally give guidance on fan maintenance so please check those in addition to the following information.

Otherwise after ensuring that the fan is safely isolated from the mains supply, periodically check the fan is free of any dust/dirt/grease build up using a damp cloth with warm water and a mild detergent.

How do I mount a fan?

window mounting

Glazing must be prepared by your glazing specialist - all other details are found in the relevant fitting and wiring instruction supplied with the product or available online

wall mounting

Core cut the relevant size hole, full details are in the releveant F&W

I have a question about my timer fan

The fan or fan and shutters do not work

It is within the warranty period

If the product as been installed in accordance to the fitting/wiring instructions and there is a supply at the fan but it does not work, then return to place of purchase for a replacement.

It is outside the warranty period

Check there is a stable supply to the fan and that the impeller is able to spin freely and there is no blockage within the fan and any duct run or termination.

Check nothing is obstructing the shutters mechanism

How do I clean my fan

The product instructions will normally give guidance on fan maintenance so please check those in addition to the following information.

Otherwise after ensuring that the fan is safely isolated from the mains supply, periodically check the fan is free of any dust/dirt/grease build up using a damp cloth with warm water and a mild detergent.

I have a query/problem with the run-on timer

The timer does not run-on at all

Ensure the fan has been wired in accordance with the fitting/wiring instructions. Timer fans require a permanent live and neutral and a switch live to operate correctly.

The timer does not time out and so the fan runs on continuously

My fan is controlled from the light switch

My lighting is low voltage or low energy and has its own transformer

Ensure there is both a permanent live and switch live on the fan or transformer controller (where applicable) and that they have been connected to correct way round. See product fitting/wiring for full relevant wiring details.

Some types of low voltage and low energy lighting (mainly older types) can create a high voltage surge at the point the light is switched and this can interfer with and in some cases damage timers in fans. If your timer fan has failed due to lighting type you will likely need to replace it. If placing on the same lighting circuit, your electricial should protect the fan with a supression device such as a Varistor of type relevant to the lighting type.

Can I adjust the run-on timer

Run-on timers can usually be adjusted between approximately 3 - 30 mins (this range varies depending on the fan). See product fitting/wiring for guidance.

How do I mount a fan?

window mounting

Glazing must be prepared by your glazing specialist - all other details are found in the relevant fitting and wiring instruction supplied with the product or available online

wall mounting

Core cut the relevant size hole, full details are in the releveant F&W

I have a question about my humidity fan

The fan or fan and shutters do not work

It is within the warranty period

If the product as been installed in accordance to the fitting/wiring instructions and there is a supply at the fan but it does not work, then return to place of purchase for a replacement.

It is outside the warranty period

Check there is a stable supply to the fan and that the impeller is able to spin freely and there is no blockage within the fan and any duct run or termination.

Check nothing is obstructing the shutters mechanism

How do I clean my fan

The product instructions will normally give guidance on fan maintenance so please check those in addition to the following information.

Otherwise after ensuring that the fan is safely isolated from the mains supply, periodically check the fan is free of any dust/dirt/grease build up using a damp cloth with warm water and a mild detergent.

I have a query/problem with the humidity sensor

The humidity sensor is not bring the fan on

It may be that the humidity level within the room is not high enough to trigger the fan. Where necessary, with most humidity fans you can adjust the sensitivity of the humidity sensor. See product fitting/wiring instructions for guidance.

Why won't my humidity fan stop running?

If you have a humidity controlled fan which is staying on most or all of the time, then there are a few points to consider before assuming the fan is faulty, as in most cases when we receive calls with suspected fault humidity fans, they are in fact operating exactly as they should be, and many are returned when there's nothing actually wrong with them.

Firstly, a newly installed humidity controlled fan will normally run for an average of half hour whilst the humidity sensor acclimatises, this is completely normal, so please leave the unit to allow it time to settle down.

Where necessary, with most humidity controlled fans, you can adjust the sensitivity of the humidity sensor. To make the fan less sensitive to humidity, you will need to adjust the sensor towards the maximum set point. Do not expect to see an instant reaction after adjusting the sensor, and please remember to leave the fan for at least half an hour to acclimatise. See the product fitting and wiring instructions for further guidance and before carrying out any maintenance or adjustments on your fan you should ensure that you have safely isolated it from the mains supply.

If your humidity controlled fan has a pull cord, it is also possible that somebody has pulled the cord to the override position, in which case the fan will run continuously until switched back to the sensor mode. Some but not all fans with a pull cord will have a neon light to indicate when the fan has been pulled to override.

Lastly, a humidity controlled fan is looking at the ambient humidity level to activate/deactivate the fan, and so it is important to remember that normal ambient humidity levels on a given day can trigger a humidity fan in just the same way as humidity generated by steam from the bath/shower room or Kitchen if the humidity level rises above the set-point. In addition, new build properties, as well as refurbished and redecorated properties will go through a drying out stage during which time the humidity level within the room will likely be high enough to trigger the fan.

I have a question about my humidity/timer fan

The fan or fan and shutters do not work

It is within the warranty period

If the product as been installed in accordance to the fitting/wiring instructions and there is a supply at the fan but it does not work, then return to place of purchase for a replacement.

It is outside the warranty period

Check there is a stable supply to the fan and that the impeller is able to spin freely and there is no blockage within the fan and any duct run or termination.

Check nothing is obstructing the shutters mechanism

How do I clean my fan

The product instructions will normally give guidance on fan maintenance so please check those in addition to the following information.

Otherwise after ensuring that the fan is safely isolated from the mains supply, periodically check the fan is free of any dust/dirt/grease build up using a damp cloth with warm water and a mild detergent.

I have a query/problem with the run-on timer

The timer does not run-on at all

Ensure the fan has been wired in accordance with the fitting/wiring instructions. Timer fans require a permanent live and neutral and a switch live to operate correctly.

The timer does not time out and so the fan runs on continuously

My fan is controlled from the light switch

My lighting is low voltage or low energy and has its own transformer

Ensure there is both a permanent live and switch live on the fan or transformer controller (where applicable) and that they have been connected to correct way round. See product fitting/wiring for full relevant wiring details.

Some types of low voltage and low energy lighting (mainly older types) can create a high voltage surge at the point the light is switched and this can interfer with and in some cases damage timers in fans. If your timer fan has failed due to lighting type you will likely need to replace it. If placing on the same lighting circuit, your electricial should protect the fan with a supression device such as a Varistor of type relevant to the lighting type.

Can I adjust the run-on timer

Run-on timers can usually be adjusted between approximately 3 - 30 mins (this range varies depending on the fan). See product fitting/wiring for guidance.

I have a query/problem with the humidity sensor

The humidity sensor is not bring the fan on

It may be that the humidity level within the room is not high enough to trigger the fan. Where necessary, with most humidity fans you can adjust the sensitivity of the humidity sensor. See product fitting/wiring instructions for guidance.

Why won't my humidity fan stop running?

If you have a humidity controlled fan which is staying on most or all of the time, then there are a few points to consider before assuming the fan is faulty, as in most cases when we receive calls with suspected fault humidity fans, they are in fact operating exactly as they should be, and many are returned when there's nothing actually wrong with them.

Firstly, a newly installed humidity controlled fan will normally run for an average of half hour whilst the humidity sensor acclimatises, this is completely normal, so please leave the unit to allow it time to settle down.

Where necessary, with most humidity controlled fans, you can adjust the sensitivity of the humidity sensor. To make the fan less sensitive to humidity, you will need to adjust the sensor towards the maximum set point. Do not expect to see an instant reaction after adjusting the sensor, and please remember to leave the fan for at least half an hour to acclimatise. See the product fitting and wiring instructions for further guidance and before carrying out any maintenance or adjustments on your fan you should ensure that you have safely isolated it from the mains supply.

If your humidity controlled fan has a pull cord, it is also possible that somebody has pulled the cord to the override position, in which case the fan will run continuously until switched back to the sensor mode. Some but not all fans with a pull cord will have a neon light to indicate when the fan has been pulled to override.

Lastly, a humidity controlled fan is looking at the ambient humidity level to activate/deactivate the fan, and so it is important to remember that normal ambient humidity levels on a given day can trigger a humidity fan in just the same way as humidity generated by steam from the bath/shower room or Kitchen if the humidity level rises above the set-point. In addition, new build properties, as well as refurbished and redecorated properties will go through a drying out stage during which time the humidity level within the room will likely be high enough to trigger the fan.

I have a question about my PIR fan

The fan or fan and shutters do not work

It is within the warranty period

If the product as been installed in accordance to the fitting/wiring instructions and there is a supply at the fan but it does not work, then return to place of purchase for a replacement.

It is outside the warranty period

Check there is a stable supply to the fan and that the impeller is able to spin freely and there is no blockage within the fan and any duct run or termination.

Check nothing is obstructing the shutters mechanism

How do I clean my fan

The product instructions will normally give guidance on fan maintenance so please check those in addition to the following information.

Otherwise after ensuring that the fan is safely isolated from the mains supply, periodically check the fan is free of any dust/dirt/grease build up using a damp cloth with warm water and a mild detergent.

I have an installation question

How much ducting can I attach to my fan

A common question, and the guidance below is more relevant to domestic type installations.

Domestic Axial fans

An axial fan has a fan blade like a ship propeller. These are low pressure fans and a general rule of thumb for these is to use no more than 1.5 metres of ducting. On a 100mm fan/ducting system, a 90 degree bend is equivalent to 1 metre, preferably rigid duct. For longer runs, a centrifugal type fan should be considered.

Domestic Centrifugal fans

A Centrifugal fan has a fan blade like a hamster wheel. The question of duct run length becomes more difficult here. Centrifugal fans are higher pressure fans and so cope better with ducted runs or where installations are in exposed positions such as an external wall prone to strong gusty winds. To know how far a Centrifugal fan is going to push the air means knowing the overall system resistance/pressure - Anything in the path of the airflow causes a resistance - this could be ducting straight lengths, bends, filters, grilles etc..... In a domestic wet room, you need to be considering a Centrifugal fan once you are over 1.5 meters of ducting, but you must still ensure that the chosen fan will achieve the required airflow for the room being ventilated with the system resistance taken into account.

Can I put more than one fan into a common duct

You should not put more than one fan into a common duct.

Each fan should have its own duct run to atmosphere. If you try to combine them into a common duct it will bring with it a number of problems, including an unbalanced system with positive/negative air pressures which play havoc with the fan motors and could cause motor failure. It can also cause cross-contamination issues.

Also not to forget that incorrect installation of the fan could void the product warranty.

In residential and some commercial applications, an alternative to multiple fans into common ducts could be a Central Extract System Fan such as our Lo-Carbon Multivent MVDC-MS or Lo-Carbon Sentinel Multivent

Why won't my humidity fan stop running?

If you have a humidity controlled fan which is staying on most or all of the time, then there are a few points to consider before assuming the fan is faulty, as in most cases when we receive calls with suspected fault humidity fans, they are in fact operating exactly as they should be, and many are returned when there's nothing actually wrong with them.

Firstly, a newly installed humidity controlled fan will normally run for an average of half hour whilst the humidity sensor acclimatises, this is completely normal, so please leave the unit to allow it time to settle down.

Where necessary, with most humidity controlled fans, you can adjust the sensitivity of the humidity sensor. To make the fan less sensitive to humidity, you will need to adjust the sensor towards the maximum set point. Do not expect to see an instant reaction after adjusting the sensor, and please remember to leave the fan for at least half an hour to acclimatise. See the product fitting and wiring instructions for further guidance and before carrying out any maintenance or adjustments on your fan you should ensure that you have safely isolated it from the mains supply.

If your humidity controlled fan has a pull cord, it is also possible that somebody has pulled the cord to the override position, in which case the fan will run continuously until switched back to the sensor mode. Some but not all fans with a pull cord will have a neon light to indicate when the fan has been pulled to override.

Lastly, a humidity controlled fan is looking at the ambient humidity level to activate/deactivate the fan, and so it is important to remember that normal ambient humidity levels on a given day can trigger a humidity fan in just the same way as humidity generated by steam from the bath/shower room or Kitchen if the humidity level rises above the set-point. In addition, new build properties, as well as refurbished and redecorated properties will go through a drying out stage during which time the humidity level within the room will likely be high enough to trigger the fan.

Electric Underfloor Heating

To assist you in answering any questions you may have about understanding, choosing and installing our electric underfloor heating we have compiled a list of frequently asked questions below.

If you do not find the answer to your question within this FAQs section, please contact us for further assistance.

What is electric underfloor heating?

Electric underfloor heating consists of a resistive cable built into the floor fabric, usually within screed or in the tile adhesive. An Electric underfloor heating system consists of a cable, either loose or manufactured onto a mat or netting and a thermostat with a floor and air temperature sensor.

Electric underfloor heating provides space heating by using the large surface area of your floor to heat your room, this allows the low temperature radiant heat to provide evenly distributed warmth giving much higher levels of comfort when compared to other more traditional methods.

Read more underfloor heating FAQs

Do I need to use insulation boards?

We would always recommend the use of 10mm thick insulation boards, this provision will increase the efficiency and warm up time of your system by limiting the downward conducted losses in the system. This will give you a more comfortable system as well as saving you money.
For applications with limited space we also offer a 6mm insulation board but the more insulation you can install the better your system will perform.

Sizing tool

Read more underfloor heating FAQs

Typical Accessories for Inline fans with Circular Connections

Click on the picture or link below to display a list of typical accessories and part numbers used with Inline fans with circular connections/spigots between 100-500mm.

The parts list is not exhaustive, but we hope it will be of assistance with general selections.

The pdf download also includes a couple of typical installation drawings to show how and where the accessories might be fitted within a ducted system.




Typical Accessories for Inline fans with Circular Connections

T-Series Matching Controllers & Typical Accessories

Click on the link below to display a list of Controls and typical accessories and part numbers used with the T-Series Range Fans.

The parts list is not exhaustive, but we hope it will be of assistance with general selections.

The pdf download also includes a typical installation drawing to show how and where some of the accessories might be fitted. We hope to add further examples in due course.

Click here to view T-Series matching controllers & typical accessories

Specific Fan Power (SFP)

We are often asked for the specific fan power (SFP) for a given fan. This is usually given at duty point, and so you would need to know the design airflow and system pressure for your application.

If you have the design duty, then you can try entering this on our Fan Selection Program, then use the filters to tailor your fan selection, and as you will see, the selection program will give you the specific fan power.

The fan selector will not contain older products, and where the information isn't within the fan selection program, you can obtain a rough guide by formula.

Specific Fan Power (SFP) = watts/ litres per second


Click HERE for Fan Selection Program

Why won't my humidity fan stop running?

If you have a humidity controlled fan which is staying on most or all of the time, then there are a few points to consider before assuming the fan is faulty, as in most cases when we receive calls with suspected fault humidity fans, they are in fact operating exactly as they should be, and many are returned when there's nothing actually wrong with them.

Firstly, a newly installed humidity controlled fan will normally run for an average of half hour whilst the humidity sensor acclimatises, this is completely normal, so please leave the unit to allow it time to settle down.

Where necessary, with most humidity controlled fans, you can adjust the sensitivity of the humidity sensor. To make the fan less sensitive to humidity, you will need to adjust the sensor towards the maximum set point. Do not expect to see an instant reaction after adjusting the sensor, and please remember to leave the fan for at least half an hour to acclimatise. See the product fitting and wiring instructions for further guidance and before carrying out any maintenance or adjustments on your fan you should ensure that you have safely isolated it from the mains supply.

If your humidity controlled fan has a pull cord, it is also possible that somebody has pulled the cord to the override position, in which case the fan will run continuously until switched back to the sensor mode. Some but not all fans with a pull cord will have a neon light to indicate when the fan has been pulled to override.

Lastly, a humidity controlled fan is looking at the ambient humidity level to activate/deactivate the fan, and so it is important to remember that normal ambient humidity levels on a given day can trigger a humidity fan in just the same way as humidity generated by steam from the bath/shower room or Kitchen if the humidity level rises above the set-point. In addition, new build properties, as well as refurbished and redecorated properties will go through a drying out stage during which time the humidity level within the room will likely be high enough to trigger the fan.

How to clean my Residential fan

How to clean my domestic extractor fan

Cleaning your fan


WARNING: THE FAN AND ANCILLARY CONTROL EQUIPMENT MUST BE ISOLATED FROM THE POWER SUPPLY DURING MAINTENANCE.

1. At intervals appropriate to the installation, the fan should be inspected and cleaned to ensure there is no build up of dirt or other deposits.
2. Wipe the inlets and front face with a damp cloth until clean. The fan has sealed for life bearings, which do not require lubrication.

How to clean my domestic Heat Recovery unit

SERVICING AND MAINTENANCE.



WARNING: THE FAN AND ANCILLARY CONTROL EQUIPMENT MUST BE ISOLATED FROM THE POWER SUPPLY DURING MAINTENANCE.

1. At intervals appropriate to the installation, the fan should be inspected and cleaned to ensure there is no build up of dirt or other deposits.
2. Wipe the inlets and front face with a damp cloth until clean. The fan has sealed for life bearings, which do not require lubrication.

In addition to the guidance above - Please click here for additional instructions on cleaning of heat recovery units.
Cleaning Instructions

How do I install the Airflow Shutter with my new Standard Range Fan/Motor

Please select from the below list:

Standard Range Window Fan - Airflow Shutter Installation

With the introduction of the Mark 3 Standard Range motor back in 2010, the installation of the airflow shutter has changed.

In years past, you could install the Airflow shutter over the pre-installed motor, however due to the design of the Mark 3 motor, you must first remove the motor to fit the shutter assembly.

Please click on the link below for a step-by-step guide on installation of the Standard Range shutter assembly in the Window Fan.