PTC Element - Features & Benefits
1/Question
I have heard about new PTC elements being used in radiators and towel rails, can you tell me what these are?
1/Answer
PTC (Positive Temperature Coefficient) technology is not new, but up to now it has been relatively expensive. Rather than controlling the heat by switching a thermostat on and off, PTC uses a natural stone to reach its optimum temperature, known as its Currie Point. Once this is reached, the power is reduced by up to 30%, to maintain the equilibrium temperature. This means that the target temperature is reached smoothly and maintained efficiently, as you don’t have the constant off/on cycling of a thermostat. An added advantage of this is that there are no working parts to wear out, so longevity of the product is greater.
2/Question
Are there any safety advantages with PTC?
2/Answer
Yes, because of the “self limiting” characteristic described above. A PTC element fitted into a towel rail on a central heating system (dual fuel), has the advantage that if it is accidentally switched on before the installer has charged the system with water, there will be no damage to the rail. If this accident occurred on a model with a traditional cartridge element, in a worse case scenario, it could result in a fire. Furthermore, a PTC element would not be damaged and would not need replacing in this situation. A traditional element would “burn out” in this circumstance. A PTC element will therefore help to eliminate costly call outs and negative customer relations.This safety feature also stays with the element through out it’s life. If at any point there is a loss of heating medium for any reason, for example, if there is a leak or if the rail is drained for decorating purposes, there will be no costly disaster if it is switched on too soon. The newer versions of PTC elements are also tested and approved to IP67. This makes it easier to specify as it gives the end user a higher level of protection, safety and peace of mind.
3/Question
It is sometimes difficult to electrify a product, because the element has to go vertically. Does this apply to PTC also?
3/Answer
If a traditional element is fitted horizontally the heat generated cannot escape quickly enough. This causes the thermostat to “flutter” i.e. switch on and off very quickly, causing a hot spot while it is working, and an irate customer once it stops working. This is not the case with PTC elements which work just as efficiently in either vertical or horizontal models. An added advantage is that some of the newer models now have an 11.5mm diameter, so that they can be fitted into smaller tube sizes, giving you even more design freedom. Also, such a small diameter reduces the likelihood of “kettling”, because you have a greater water jacket around the element.
4/Question
Does PTC have any benefits that can be used as USP’s to the end user, or are they only really hidden technical advantages?
4/Answer
The safety and eco benefits already described will certainly be features that can “sell” a product to the end user. However, it is worth noting that some of the more technical characteristics can certainly be translated into USP’s to help installers clinch a sale in these very competitive market conditions. For example, in the first 60 seconds of operation, the element will work at 130% of nominal power. This “turbo boost” will help to get the optimum circulation inside the appliance. This is particularly useful if the appliance has been standing idle for some time, for example in a holiday home. Once the element has reached equilibrium, the power reduces to a level to maintain the desired temperature. However, if a wet towel is placed on the appliance, the element will automatically return to full power until the towel is dry and then revert to its power saving mode. PTC elements can also be used with a range of controllers to allow the customer to reduce the surface temperature.
5/Question
Is a PTC element going to cost me a lot more than a standard cartridge element?
5/Answer
No, technical and manufacturing efficiencies are such that now you should be able to buy a PTC element for around the same cost as a traditional cartridge element.