Immersion heater noise

[Johnnorman40]

I had a new water heater element fitted a few weeks ago that heats water at night on economy 7. Previous heater elements have been very quiet but I can hear the new one heating the tank at night. It sounds a bit like a boiling kettle. Is this normal? It’s driving me mad!

 

[John.g]

No John, not normal, are you sure that its not actually boiling?, maybe not installed correctly with its thermostat bypassed or faulty, measure the HW temperature, if its noisy once it starts heating though, above unlikely.
Kettling normally occurs when limestone builds up on the heating element but obviously not on a new element, its possible I suppose that your cylinder is "full" of limescale and in close proximity to the heating element?..Have you replaced this element frequently.

 

[Johnnorman40]

No John, not normal, are you sure that its not actually boiling?, maybe not installed correctly with its thermostat bypassed or faulty, measure the HW temperature, if its noisy once it starts heating though, above unlikely.
Kettling normally occurs when limestone builds up on the heating element but obviously not on a new element, its possible I suppose that your cylinder is "full" of limescale and in close proximity to the heating element?..Have you replaced this element frequently.

It’s been replaced twice in the last 5 years. The hot water temp is 70 degrees C first thing in the morning. The issue only started when the new element was installed. Should I contact the plumber that installed it?

 

[John.g]

Only lasting say 2.5 years might indicate some cylinder problem, is it noisy from the time it commences heating??, if so would contact the installer.

 

[exedon2]

I've had a couple of customers complain of noise when we have swapped standard immersion heaters for titanium one's.
Had to swap one back to normal copper one which to be fair was much quieter.

 

[Chuck]

I suspect your plumber didn't fit a "low watts density" immersion heater, which is the type you want. These are quieter and have longer life than than the standard type.

 

[John.g]

Two 3kw low watts density immersions, below, presume both of these have the same element surface area??.

 

[Chuck]

Two 3kw low watts density immersions, below, presume both of these have the same element surface area??.

There will be a value on the spec sheet, something like "7 W/cm^2", which when multiplied by the active area of the element, e.g. 400 cm^2, gives the total dissipation, 2.8 kW in this example. You can estimate the area with callipers and a tape measure. There is usually about 10cm of inactive area so the mounting doesn't overheat.

 

[John.g]

I've seen something like that.
I measured the element area of a 9kw electric shower a while ago and came up with something like 21w/cm2 and the only singing I hear is myself, of course its a forced flow through the heating can but still and all the residence time is only ~ 3.4 secs at a flow rate of 4LPM as the can only holds 225ml. Electric kettles must have a pretty high density as well hence the "kettling" from the very start on switch on?.