Immersion heater: water not hot enough

[Jamierez]

I replaced the heater element in my boiler at the weekend. Since then, there has not been as much hot water as with the previous element. I've checked the thermostat and it is set to the maximum allowed (unknown value). Its definitely at the maximum (double checked by using multimeter and varied output).

Now there are two differences from the previous element. 1) Its a super alloy based one as opposed to the previous copper one. 2) The length of the element is shorter than the previous one (11" opposed to 14").

Is the length of the element a problem? I would have thought it would have just taken longer to heat up. Could it be the thermostat being set too low? The maximum has been limited by the manufacturer.

Any help would be appreciated.

 

[JohnD]

When you say "boiler" I think you mean Cylinder. Boilers do not have immersion heaters.

If the element is inserted through the top of the cylinder the short element will only heat the water at the top of the cylinder. A 27" element will heat about 2.5 times more water than an 11" one.

The hot water rises to the top of the cylinder and stays there. It does not pass heat to the bottom of the cylinder.

With your recent experience, you should be able to fit a new, longer element quite easily.

You should adjust the thermostat to about 60 degrees. If you turn it too high it might overheat and cut out. Whatever you do to it it will be incapable of heating the whole cylinder. However it will give you a small amount of hot water quite quickly.

You also need to insulate the cylinder well or it will lose the heat you have purchased at great cost and act as an expensive radiator.

 

[kevplumb]

err whats a "Boiulers" john

 

[JohnD]

A speling migtake or a mystipe.

 

[Jamierez]

When you say "boiler" I think you mean Cyulinder. Boiulers do not have immersion heaters.

If the element is inserted through the top of the cylinder the short element will only heat the water at the top of the cylinder. A 27" element will heat about 2.5 times more water than an 11" one.

The hot water rises to the top of the cylinder and stays there. It does not pass heat to the bottom of the cylinder.

You should adjust the thermostat to about 60 degrees. If you turn it too high it might overheat and cut out. Whatever you do to it it will be incapable of heating the whole cylinder. However it will give you a small amount of hot water quite quickly.

Thanks for the response. I did mean to say a cylinder not boiler, doh! It is a side entry element, so will take up to a 14" element. I was unable to source a 14" Alloy element, so went for the 11" variant instead. Is this the problem? Want to make sure before ordering one of the net. I've checked the manufacturers specs for the thermostat and it is factory limited to 60 degrees and it is set to that at the moment.

 

[kevplumb]

 

[kevplumb]

side entry should be at the bottom anyhoo

 

[Jamierez]

side entry should be at the bottom anyhoo

Yup, its at the bottom.

 

[JohnD]

you could look up the wattage of your element.

On the (rare) dual element ones, the long one is about 3kW and the short one is about 2kW.

I have seen people bend the long ones to fit but don't know if you're supposed to.

Tell us about the cylinder insulation.

 

[WDIK]

you could look up the wattage of your element.

On the (rare) dual element ones, the long one is about 3kW and the short one is about 2kW.

I have seen people bend the long ones to fit but don't know if you're supposed to.

Tell us about the cylinder insulation.

yup

 

[Gasguru]

Try another thermostat...I've had a few switching off too soon.