Hissing/boiling sound when immersion heater on.

Prenderb · 30-12-2010 1:10pm #1

Hi all, I'm puzzled the last day or 2 by a hissing noise, a little like a kettle boiling, when the immersion heater is on. I've checked the system for air ( in the hotpress valve) and let out a little but the noise is still there. Anyone any ideas fir where else to look with this? It's not normal, we've never heard it in 4yeara!

Buford T Justice · 30-12-2010 1:33pm

Is the water in the tank hot?

The stat in the immersion could be faulty and the water could be boiling over.

Prenderb · 30-12-2010 1:46pm

Yeah the waters hot alright, someones just had a bath. Will check thermostat, though I think it was fine earlier.

Prenderb · 30-12-2010 2:08pm

Actually, I was checking the stat mounted externally, which I reckon is for the boiler. Is there a stat on the immersion heater itself? Is it a question of just unscrewing it to check?

mp22 · 30-12-2010 2:30pm

Turn the immersion off, unscrew one or two screws then carefully remove the cover on the immersion.(make sure it is off as there is 30 plus amps of power in there)

Prenderb · 30-12-2010 3:47pm

Should I be wary of pressurised hot/warm water?

mp22 · 30-12-2010 4:18pm

Prenderb wrote: »

Should I be wary of pressurised hot/warm water?

No if there is water under the plastic cover you would not have a working immersion.The temp adj is beside the electrical connections

meercat · 30-12-2010 10:55pm

http://www.diydata.com/problem/immersion/immersion_heaters.php
remember to turn power off before going near this job

Prenderb · 31-12-2010 12:41am

meercat wrote: »

http://www.diydata.com/problem/immersion/immersion_heaters.php

Helpful link thanks - and of course your advice is noted! TBH I'm not noticing that the hot water is particularly hotter than usual. Maybe this is an early sign?

Could hard water have anything to do with the noise? I haven't had a chance to
open the cover and see about the thermostat - visitors doncha know.

Dan Jaman · 31-12-2010 4:46pm

It's common for immersion heaters to make a hissing noise in hard water areas. Nothing to worry about, but the scale is building up on the element and it might not last another year, depending on useage. If you have an unlagged cylinder, the noise is louder, of course.

Sparkpea · 01-01-2011 1:05am

I agree a kettle/hissing type noise is fairly normal in my opnion

Prenderb · 01-01-2011 1:21pm

Thanks for all the replies guys. Have just also noticed that there doesn't seem to be any water coming through the top-up feed from the attic tank at the moment. Might be an airlock there if there was ice in the feed, could that be connected to the hissing noise either? There was more air released from the air release valve this morning.

Feel like such a noob!

HAven't checked element or element 'stat yet, btw.

Buford T Justice · 02-01-2011 12:26am

The Hot water in the Cylinder is filled from the bottom, and drains out to the taps from the top.

Sparkpea · 02-01-2011 10:12am

do you boys find the new immersions hiss/boil more now than they did years ago? sometimes they can be seen to shake when the element is heating. the copper body is probably not as strong as it used to be.

Dan Jaman · 02-01-2011 1:27pm

The cylinders are made of pretty thin copper nowadays, but it's still possible to buy a decent quality one - for a price.

Jimibo · 17-02-2020 9:35am

Hi, my heater is making a noise as well. I'm wondering if I should de-scale it. Has anyone done that?

dodzy · 19-02-2020 1:05pm

Panic stations setting in people. A slight buzzing from the tank is normal. If there no problem with you hot water supply, then leave alone. The elements have a life span (shorter in hard water areas ) but sure when it does pack in, you will know about it as there will be most likely an RCD trip on the consumer unit or possibly no hot water when when one of either bath or sink is selected. Address it then.

And forget about descaling.

Hissing/boiling sound when immersion heater on.

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