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Frequently Asked Questions


Heat Transfer

How long is the maximum length of ducting I can use to transfer heat effectively?

The maximum single run length is 9m, with 15m of ducting supplied in total. The maximum length of ducting to effectively transfer heat is 9m long – any longer and you are battling physics in terms of moving hot air and losing temperature as it travels. So the shorter and straighter the lengths of ducting the more effectively your heat transfer will work.


I have an old round heat transfer vent in my ceiling. How do I find a replacement?

Measure the outer diameter of the vent fascia.

  • If it is a dinner-size plate (lounge or inlet 280mm) then the part code for replacement is 200SET

  • If it is a bread-and-butter-sized plate (bedroom or outlet 200mm) then the part code is HSADJVENT-150

These are available from your local Mitre 10 or electrical wholesaler.


How powerful is the motor?

The motor performance depends on which unit you have. The technical specifications for the motors are available on the downloadable data sheet.


What is the replacement motor for my heat transfer system?

Replacement motors are as follows:

  • Motor for model FV601 is FV05CP

  • Motor for model FV662 is FV06CP

  • Motor for model FV663 is FV16CP

  • Motor for model FV604 is FV16CP

  • Motor for HT125-2 and HT125-3 is FV16CP


What are your installation recommendations?

As per the picture in the instructions included with the product, we recommend that you tape the w or y junction to the fan and then place the metal clamp over the tape to secure it onto the fan.

The fan should be suspended using cable ties to reduce the noise, but the ducting can just lie on top of the insulation in your ceiling cavity.  The motor comes with a mounting of its own.  Please ensure there is a drip loop in the supply cable.


Why is the ducting expensive in a heat transfer system?

Because you are installing a heat transfer system, your ducting needs to be insulated. This makes it a bit more expensive, but the insulation is necessary to retain the heat.


What electrical compliance is required for the installation of a heat transfer system?

You do need to make sure that a registered electrician installs and issues a certificate of compliance for all the wiring requirements for this system. This is necessary for both insurance and product warranty registration. (In reality, it’s probably only making sure that the socket in the ceiling cavity has a certificate of compliance, and that the thermostat has been terminated correctly.)

Troubleshooting issues with Heat Transfer

A few things might affect the performance of heat transfer units:

  • The temperature of the fire in the source room and the temperature that the thermostat is set at - The air will lose approximately half a degree per metre travelled after the system has warmed up.

  • Check that your thermostat is set to 25 degrees (or desired transfer temperature) and the fan will only come on when the room (with the heat source where the thermostat is located) is above that temperature. If this is not the case, it may have been wired to the incorrect terminals in the thermostat i.e. to turn off when it reaches 25 degrees

  • Horseshoe shapes in ducting are not ideal. The most effective configuration is a straight run, but you should appreciate that may not always be possible.

  • Check the location of the vent to ensure it is not sucking cooler air from somewhere else.

Home Ventilation

Can I upgrade an existing system with heat transfer or fresh kit?

It depends on the system you have installed. The FV802 is the oldest system and this cannot be upgraded. Please email a photo of your control pad to, noting your location so we can provide you with the relevant information.


Which system do I have?

Please email a photo of the control pad to


Where can I get a filter for my ventilation system?

Mitre 10, Mico, Plumbing World and any of the electrical wholesalers.


What is the part code for my filter?

  • FV4LCD S touch ventilation - 33 F6

  • FV802 - FV82

  • FV814 - FV84


How do I reset my system after changing the filter?

Check this website for instructions (LINK TO PAGE)


My Control Pad keeps beeping – how do I stop it?

The main cause of beeping is that the touch screen (keypad) is too tightly screwed into the wall. If you remove the half-moon shapes on the key pad there are two screws underneath that you can loosen about a half turn and that should stop the beeping.


I am interested in purchasing a home ventilation system. Can you provide more information please?

Weiss have been designing home ventilation systems for NZ conditions for 20 years. Our systems have smart technology for both the motor and the controller, which means they operate automatically.

Our systems have a wide range of different speeds, combined with humidity sensing technology and we have been working to ensure that they are quiet – even at higher speeds. They can be installed by anyone on the proviso that there is a power point in the ceiling cavity that the system can be connected to. If not, then you will need an electrician to install one.

Noise level of fans

Which fans can go above the shower and which are only allowed outside splash zone?

Above the shower:

FV102, FV105, FV106, FV107, FV110, FV130, FV160 and FV160LED

(7th June 2016. Electrical safety in bathrooms divides into 4 zones. In zone ‘0’, which defines being within the sink bowl, bathtub or shower cubicle, any electrical appliance must be direct current and low voltage)

Not in splash zone:

FV200 and FV120SS, FV120WH cannot be used in zone 0 and must be a minimum of 200mm from the shower or in zone 2. This is still allowed in a bathroom, just not in the shower.

Through wall fans

Do you have a through wall extractor fan?

Yes. Model FV155.


Does the Weiss through wall fan come with a cowl/ backdraft flap?

No. It comes with a standard vent, but Weiss backdraft flaps and cowls are available separately from your supplier.

Service agent

Can Weiss recommend an installer for a home ventilation system?

Yes. See below for various regions:

Waikato – Bill Rees – Goldstar Heat pump Services

Auckland – Steve Campbell – Jarifin Electrical

Christchurch – Aotea Electric Canterbury Ltd

Dunedin – Aotea electric Southern and Security Ltd

Nelson – Aotea Electric Nelson Ltd

Hawera – Kensair Ltd

Tauranga – Switch Electrical

Fan timer

Can I put a timer on my bathroom heater?

No. It will cause the timer to fail immediately.


Can I put a timer on my bathroom Extraction fan?

Yes. Any of the following bathroom extractor fans will work with a Weiss Timer:

FV155, FV102, FV105, FV106, FV107, FV110, FV130, FV160 and FV160LED.

Please note: Manrose timers are not compatible with Weiss fans.

Obsolete products

I have an FH705D. Can I replace the motor?

Yes. The motor replacement is part code WM705.

Where can I get an FH800?

This is an obsolete product that is no longer available.

I have an FV814 / FV801 / FV802. Can I replace the motor?

No. FV814 / FV801 / FV802 are now an obsolete products. However, we can upgrade the fan and the control pad. Please email for further information.


Where can I get a PH400 panel heater?

This is an obsolete product and there are only factory seconds available. They are still functional but may have minor scratches or dents on the front panel. Please email for further information.


I purchased an SM3500 a few years back and would like to get another one. Where are they available?

This is now an obsolete product and is no longer available.


What are your recommendations for Installing a bathroom heater?

Any object needs to be at least 700mm below the heater as per the unit instructions. This heater also needs to be at least 200mm from the ceiling because this will trip the thermal fuse if the heater is too high.

I have an FH24/FH30 bathroom heater and the pull cord has snapped. How do I get it fixed?

The heater pull cord replacement is a very simple repair you can do it yourself. Instructions are downloadable from this website. (FH24 or FH30 models)


What are the dimensions/measurements of your bathroom heater?

Measurements and dimensions are provided on the downloadable data sheet.


My bathroom heater is broken. Do you have parts available or can you recommend a repairer?

No. Unfortunately, no parts are available (including wall mounts). If your heater is broken and it’s out of warranty period, then the only option is to replace it.


Will your heater replace my old SKOPE recessed wall heater?

The only Weiss recessed wall heater available is the FM2400. The dimensions are available on the downloadable data sheet.


What are the main differences between the SM2400 and the SM2400BMS?

The SM2400BMS is designed to function with a building management system and controlled remotely. The SM2400 has the ability to turn on and off according to time or temperature in the room being maintained. It may also be turned on and off manually at the heater.


Do you have a wi-fi app to turn the SM2400 heater on remotely?

No. This is not available.


I have an FH706/FH706LED. What is the code for the middle light bulb (not the heatlamp)?

The part code for this bulb halogen version is GU10 and the LED version is T-L6MR16-5W-GU10. If you need the heatlamp, the part code is FH275.


I have and FV160/FV160LED. What is the code for the middle light bulb?

The part code for this bulb halogen version is MR-130 and the LED version is MR165WWW.

Light Bulb change

I have an FV160LED. How do I replace the centre light bulb?

The bulb is quite a tight fit because we don’t want water getting in there. We recommend that you get up on a step ladder (safely inside a wet environment, of course) so that you are closer to the bulb. Hold on to the outer ring, pushing up lightly with one hand. Then you essentially just grip the bulb with your fingernails around the edge and pull the bulb straight down.  Reverse this process for replacing it. You will see there are 2 little pins that when you replace the bulb, just push straight up.  

Insulation rating on fans/ducting

What is the insulation rating on Weiss ducting?

The insulation rating of our ducting is R0.6.


When should I use a cowl as opposed to a gravity shutter?

Cowls are most suited to high weather exposure environments/locations, as the hooded cowl affords extra protection from the elements.


When do I use a backdraft flap?

A backdraft flap outlet is most suited for areas that are somewhat sheltered. Backdraft flap outlets must be wall mounted.


I am looking for an electric/autoclosing backdraft flap. Do you sell those?

No. We do not sell electric/autoclosing backdraft flaps.


I need to replace just the ring on my FV160/FV160LED. What is the part code?

The part code for the ceiling ring on the FV160/FV160LED is MP644.


I have an old FH705D. Can I just get a new front piece replaced for my new bathroom renovation?

Yes. The fascia is part code 72050. It is available from Mitre 10, Mico, Plumbing World or any of the electrical wholesalers.


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