FAQ

I have bought a house fitted with LVI radiators, but unfortunately there is no instruction manual. Can you help me?

You can view or download instruction manuals from our website [Mounting/Installation & Care].

Who should I contact if there is a fault with a radiator?

You should first contact the electrician who installed the product or one of our resellers. Otherwise, you should contact LVI.

What does linear measure (L), specified in our tables, stand for?

The linear measure is the total length, including the thermostat.

What happens if the output of the radiator I have chosen is too high or too low?

Too high output: There will be an uneven distribution of heat, increased discomfort and a downdraught of cold air can come from the window. Too low output: The radiator is constantly set on maximum output and still does not succeed in heating the room. It is not a good idea to have an under-sized radiator that is constantly overworking. Use the standard calculation: 75W/m² or 30W/m³, + 20% if badly insulated in order to work out the exact output required.

Is it possible to connect two oil-filled radiators together and use one thermostat for both, e.g. in a room with two electric radiators?

Yes, they must be connected as slave radiators, otherwise they will work against each other. The majority of our models can be connected as slaves and our website shows which ones these are.

How do you set a frost guard on electric radiators?

On some of our models there is a special frost guard setting (*). In this case, a temperature of approximately 7 degrees Celsius is maintained.

Which electric radiators may be used in “wet areas” such as toilets and bathrooms?

Electric radiators with the lowest IP21 protection class that are installed using fixed installation in zone 3. Electric radiators with the lowest IP44 protection class that are installed using fixed installation in zone 2. Follow the current regulations and our instructions on installation.

Is it possible to mount an oil-filled radiator edgeways or with the thermostat at the top?

NO, absolutely not. If you require a vertical radiator, we have special radiators for this purpose. Our cast granite radiators are also available in a vertical model and can be mounted “edgeways”.

Why is there no earth connection on cast granite radiators?

Cast granite radiators are double insulated and cannot be earthed.

What type of circuit breakers are used for electric radiators?

A 2-pole circuit breaker is used for all of our models.

Are there any models that can be supported by feet?

The models Alata (CEB) and Kaba (CE) allow the option of being supported by feet. All other models have only been approved for fixed mounting.

Is there any form of guard to prevent anyone from adjusting the thermostat?

It varies slightly according to the model. On models Yali (MEC) and Yali L (MEB60) there is a little pin in the cover, which means that you can lock it using a small tool. The Alata (CEB) also has a lockable cover. The M model has a little fitting that can be mounted in front of the circuit breaker and thermostat knob.

Is it possible to have the thermostat on the left-hand side?

Models Alata (CEB) and Kaba (CE) are reversible and can be mounted with the thermostat on the left-hand side. All other models can only be mounted with the thermostat on the right-hand side.

Is it possible to combine different radiator outputs in the same room, or combine oil-filled and open radiators?

Yes, it is possible. You can have different outputs and different radiators in the same room, but the most important thing is that you have the correct total output. See question and answer above. We recommend placing the radiators under windows to prevent the downdraught of cold air.

How do you calculate the output you require in your house?

You can use 70-75 W/m² or 30 W/m³ as a standard calculation. Always round off upwards. You should add approximately 20% if the house is draughty or badly insulated.

What is the difference between a direct and an indirect system?

A direct system is one where the tap water actually mixes with the water in the radiators. An indirect system separates the tap water from the radiator water, and can also be called a “closed” system. PURMO radiators can only be fitted to an indirect system.

When do I need to use Low Surface Temperature radiators?

LST radiators are an ideal choice wherever high efficiency heating is required, yet where safety demands a low surface temperature, ie. where people may injure themselves if left in contact with a standard radiator. The PURMO Safety Radiator never runs above a maximum 43°C and is ideal for hospitals, nurseries and residential homes, as well as children’s bedrooms.

How can I prove that a radiator has frozen?

Nearly all people suffering a frozen radiator do not agree with the diagnosis. Often, the customer incorrectly believes that the temperature in the room did not fall to below freezing point because a) he trusts his room thermostat, or b) claims that because the other rooms are heated it is not possible for anywhere else in his house to freeze.

There are, of course, ways to prove that a radiator has indeed frozen:

1. the upper water channel will have been deformed by the expansion process of the change from water into ice. The water channel will be wavy and crooked, usually along the whole length of the radiator.
2. the steel between the weld points will have bulged as a result of the expansion of the ice. This bulging of the steel between the weld points will be worse at the top and less serious at the bottom.
3. the steel will be cracked, usually at the top weld points or at the connection box.

There is no doubt that a radiator which displays this degree of deformity has frozen. The pressure exerted on a radiator when freezing takes place is +/- 20 bar. PURMO conducts regular tests on radiators to test their pressure resistance. At +/- 20 bar (the normal test pressure for all radiators amounts to 8 bar, and the guaranteed working pressure is 6 bar) the radiator will start to display exactly the same characteristics as a frozen radiator. This pressure cannot be caused by the central heating water itself, the poor quality of the steel or by another manufacturing fault.

A frozen radiator is always a minor disaster for the customer as they are responsible for the water damage and must pay the costs themselves. It is therefore understandable that they will argue against the conclusion that the radiator froze. Unfortunately, this brings a climate of dissatisfaction and bad publicity for the radiator. Therefore, to prevent such negative occurrences, all the necessary measures need to be taken before and during installation, and the customer is also to be informed about the consequences of spaces that are barely heated or not at all.

How can frozen radiators be avoided?

1. Always fit radiators with thermostat valves. This will guarantee that a supply of warm central heating water remains available. You must, however, always ensure that you do not fully shut the thermostat valve, but turn it to the star.

2. Do not set the night temperature too low. Most people have a room thermostat in the living room. If this is set to 15°C at night and this temperature is maintained in the room, the thermostat will send a message to the boiler to stop heating for the time being. This is dangerous for the radiators in other rooms. The temperature in the living room may stay at around +/- 15°C for a long time, whilst the temperature in the veranda falls below zero. Because the boiler has stopped heating, the radiator in the veranda will freeze.

3. When you are away from home (whether for a relatively short time or for a few days) do not change the settings of the radiators, boiler or the thermostats.

4. Do not assume that heat produced in adjacent spaces will automatically ensure that the spaces you do not heat will be kept frost-free. In other words, make sure that each space is always (at any time of the day or year) provided with the necessary minimum heating.

How and why do radiators freeze?

Household spaces that, in the winter, are either never or rarely heated are called "risk spaces". Examples include: verandas; garages; spare bedrooms; attics; cellars; halls; storage spaces; washing spaces and even living rooms that are not heated in the winter for budgetary reasons. (PURMO's service department has never encountered a frozen radiator in a kitchen or bathroom.)

If these spaces are not heated, the temperatures fall below freezing point and the water inside the radiator turns to ice, causing the radiator to crack, or even explode because of the enormous pressure of the frozen and expanded water (ice). This can lead to the radiator being ruined and needing to be replaced. If thawing takes place, water will spout out of the radiator causing a great deal of damage.

Why can I hear sounds in my radiators?

• a clack-clack-clack sound indicates an incorrect connection with inflow and outflow exchanged.
• a hissing sound indicates that the flow-rate is too high through the valve, caused by the pressure being too high.
• a tick-tick-tick sound indicates there is tension in the system in the pipes, the radiator, and the wall units.

This is common in winter when temperatures outside drop to freezing. A radiator that is not protected against frost inside can freeze. This doesn’t only happen in houses still being built, it can also happen in houses that are already inhabited.

Why are there cold spots in my radiators?

These can be caused by any of the following:

• the system is not balanced correctly.
• the conveying height of the circulation pump is too low or the pump is running at too low a power setting, which causes the flow-rate in certain circuits to be too small.
• there is too much air in the system.
• the thermostat control is covered by an item of furniture, or curtains. This causes the temperature at the thermostat to be significantly higher than in the room itself, which in turn causes the valve to be completely or partially closed and the flow-rate to decrease.
• the thermostat control is not being used correctly.
• the main thermostat is being subjected to large external sources of heat, such as the sun's rays. Since the main thermostat has reached the desired temperature, the radiators in other rooms do not heat up.
• the water temperature is too low.
• the radiator is too long: if both the inflow and outflow connections are at the same end, the water might not be flowing through all of the radiator. For long radiators, the connections should be at opposite corners.
• impurities in the valve unit. When the system is filled with water, suspended particles can collect at the valve and decrease the flow significantly.
• the radiator is only partially warm: a phenomenon which is sometimes easy to explain. When the desired room temperature is reached, the valve will close, even if the radiator is not yet completely filled.

I have bought a house fitted with an LVI towel warmer, but unfortunately there is no instruction manual. Can you help me?

You can view or download instruction manuals from our website [Mounting/Installation & Care].

Who should I contact if there is a fault with a towel warmer?

You should first contact the electrician who installed the product or one of our resellers. Otherwise, you should contact LVI.

I want to buy a towel warmer in another colour (rather than chrome and white) to match my bathroom. What other colours are available?

Our combined cast granite towel warmers and bathroom radiators Milo V (SET) are available in granite colours (white, grey, dark grey and sand). The Bandai IR (Paris IR) is available with a silver gloss finish. The Bandai IR (Paris IR) can also be specially ordered in a number of other colours.

Do you have any towel warmers that are double insulated?

Yes, all our models except for the Nila/Nila R (TF/TFR) and Muria/Muria R (TT/TTR) are double insulated. It is mentioned in our instructions on installation and on the product itself.

What type of circuit breakers are used for towel warmers?

A 2-pole circuit breaker is used for models: Athena (ATHEN), Nila/Nila R (TF/TFR), Muria/Muria R (TT/TTR), Milo V (SET).

How do you mount the Milo TR (HDH) towel rail?

It is screwed tight into the wall.

How many Milo TR (HDH) towel rails can be mounted on a vertical Milo V (SET) cast granite radiator?

It depends on the height of the Milo radiator. The Milo TR (HDH) consists of two rails with a fixed measurement of approximately 27 centimetres in between. In order for it to have space and look attractive, you cannot mount two Milo TR (HDH) towel rails on the Milo V 08 03 (SET 30804) or the Milo V 09 04 (SET 40906).

Should the towel warmer only be used for drying towels?

No, we recommend that you have the towel warmer on 24 hours a day all year round. Our towel warmers only use between 40-100W (similar to a light bulb) so the energy consumption is low. The advantage of having the towel warmer on constantly is that you experience better air circulation in the bathroom and the risk of damage caused by moisture and mould is reduced. This is particularly important during the summer, when the normal heating is off.

Are the models Athena (Athen)/Nila (TF)/Nila R (TFR) fully equipped for concealed mounting?

Yes, they are fully equipped so that you can choose between visible or concealed mounting. You do not need to buy anything else.

I have a hydronic heating system in the house. Do you have any towel warmers for hydronic systems?

Yes. The Alaid X (OSLO MIX) is a combined hydronic and electric towel warmer. In the winter, when you use your heating system, you can operate the towel warmer with water. When you turn off the heating system (e.g. spring, summer, late summer) you can then simply connect your towel warmer to electricity. As a result, your towels will be warm and dry all year round. The Alaid X (OSLO Mix) is fully equipped with a water valve and electronic thermostat.

Is it possible to mount models Jarl (TFT)/Alaid (OSLO)/Bandai (PARIS) with the connection housing on either the right or left-hand side?

The connection housing is mounted on the right-hand side with a visible cable.

Is it possible to mount models Nila/Nila R (TF/TFR) or Muria/Muria R (TT/TTR) with the connection housing on either the right or left-hand side?

Yes, as long as you mount it on the lower part you can mount it on whatever side you wish.

Can a towel warmer be mounted with the circuit breaker box at the top?

It depends on the model. If it is a towel warmer with fluid in, the circuit breaker box must always be mounted at floor level because that is where the immersion heater is fitted. However, if it is a towel warmer with a heating cable inside (Athena), it can be mounted with the circuit breaker at the top, at the bottom, on the left or right-hand side. It mentions in the instruction manual what is important for each model.

How do towel warmers/electric radiators work together with underfloor heating?

The smaller towel warmers work fine together with underfloor heating as they operate at a constant temperature (fixed or variable) regardless of what the temperature of the underfloor heating is.
The larger combined towel warmers and bathroom radiators have in-built thermostats that sense the room temperature. The underfloor heating also has a thermostat that senses the temperature. As a result of this, there is the risk of the two systems working against each other with only one of them providing heat and the other remaining cold. However, this can be overcome by lowering the thermostat on the towel warmer and then using the “boost function” that some of our models are equipped with. (The towel warmer operates on maximum for two hours when programmed regardless of the room temperature, before returning to normal).