Tesla (UK) Ltd

[Javascript protected email address]

Over 20 years' experience in manufacturing, product development and distribution

Technical Issues - FAQs

Q. Immersion Heater - My Immersion Heater keeps tripping out and I have to press the reset button to restart it.

A. There are a number of causes of nuisance trip-outs, but often they can be cured simply by reducing the temperature setting on the thermostat. If this does not cure the problem or the resulting water temperature is not warm enough then the following should be considered: 1) The ambient temperature in the surrounding area of the immersion heater is to high. The airing cupboard door needs to have ventilation at the bottom to draw cooler air in and the roof or ceiling above the cylinder needs to be ventilated to take the hot air away. 2) The immersion heater is not fully immersed in water. This may happen due to the design of the cylinder which allows an air pocket to form below the immersion heater, or where there is a pump (e.g. power shower) and the cold-water feed is unable to maintain the water level. 3) The element has become heavily coated in limescale. The rate of limescale deposit is affected by the hardness of the water, the thermostat setting, and the amount of use, but excessive limescale has been seen in elements after less than 6 months. Reducing the temperature can help, but if you are in a hard water area we would recommend a titanium immersion heater.

Q. Immersion Heater - Why is the new side mounted element I fitted making a boiling / bubbling noise?

A. Possibly because the element is not the same model as the one that was removed. Try fitting a 14" element with a Double Bend.

Q. Immersion Heater - Should I use a sealing compound on the 2 1/4'' thread?

A. No, you only really need to use the washer provided although PTFE tape may help if needed. PTFE tape is also a good lubricant and will help if the immersion heater is removed in the future. Also, make sure all sealing surfaces are clean before fitting the element and that no sealant get into the tank or on the element surface itself.

Q. Immersion Heater - Why is the water just getting warm and not hot?

A. Try increasing the temperature that the thermostat is set to, but please ensure that the correct size of element has been fitted to the cylinder.

Q. Why with the old immersion heater could we get steaming hot water and now the new one is nowhere near as hot?

A. The new EN standard means that we cannot allow the upper limit of the control thermostat circuit to rise above 70 Degrees C as this will cause ambient temperature problems with nuisance trip outs due to interference with the secondary safety circuit.

Q. Why is there water in the base of the brass head of the Immersion Heater?

A. That means that there is a potential leak through the thermostat pocket. Please contact us.

Q. Why is the wiring inside the head of the immersion heater burnt?

A. Invariably this is due to an electrical short. Ensure that the wires into the thermostat are securely in place and the retaining screws are suitably secured onto the bared copper wires but NOT over tightened.

Q. Immersion Heater - I have a dead unit with no electrical continuity between the live and neutral terminals. What can I do?

A. Please call us for guidance.

Q. Immersion Heater - What can I do with a dead short between the live or neutral terminals and earth?

A. Please call us for guidance.

Q. What can I do if the circuit breaker trips at the board when the immersion heater is turned on?

A. Generally, this will be because the circuit breaker is of insufficient rating. Please ensure that the circuit breaker fitted has a minimum rating of 25amp and is on its own circuit and that nothing else is connected OR the element has a 'dead short'. Please consult a qualified electrician if in any doubt.

Q. There is covering of something on the sheathing of the immersion heater and it has stopped working. Why?

A. This will probably be a covering of limescale which has come from hard water and has effectively 'choked' the element. A new element of either Incoloy or Titanium should be refitted.

Q. I have a dead unit with no electrical continuity between the live and neutral terminals. What can I do

A. If the heater has failed prematurely it may be due to one of the following causes: (1) Excessive limescale build up caused failure (we advise titanium in hard or very hard water areas) (2) Element damaged due to not being fully immersed when activated - evidence of this is if the element of a copper immersion has turned a pink colour, or an incoloy or titanium immersion has turned a darker colour.

Q. A leak has developed in the thermostat pocket.

A. If an immersion heater with a copper thermostat pocket is fitted into a stainless steel cylinder then galvanic corrosion will erode the copper pocket and it will start leaking after a short period of time.

Q. My Towel Rail Element has suddenly stopped working.

A. A common cause of failure is that the towel rail has insufficient fluid to properly cover the heating element. In this instance the element will overheat and the internal thermal fuse will burn out to protect any further damage. It is essential when installing a Towel Rail Element in an electric only system that all the ports on the towel rail are sealed properly to prevent any water or vapour from escaping. It is especially important to check the upper ports as any escaping vapour will be invisible.

Q. I can't remove the plastic cap

A. Twist the cap until a point is found where it feels a more free fit on the heating element. Rock the cap backwards and forwards while pulling on it and it should come free.