immersion heater thermostat setting All aspects of plumbing questions and answers, help, tips and information

[Dino]

What setting on the thermostat setting dial delivers the most and hottest
water, I have tried all settings and the longest it stays on is one hour not giving up enough hot water I need the heater to stay on at least one hour and a half for decent bath, but clicks off after one hour...Dino

[marrtin]

The dial on the top of the immersion is a thermostat, and is designed to set the temperature of the water, and not the length of time the heater is on. It is normal for this to be set at no more than 60 deg C.

If you find the water that first flows is suitably hot, but runs out when filling a bath say, the problem is probably more to do with a wrong immersion or stat being fitted.

Elements are available in two lengths. If the 11 inch version is fitted, then only the top 11 inches of water can be heated.

[peter the plumber]

You sound like my wife and I am telling you what I told her.

Right it’s not the cylinder or the thermostat, its you!

There about 115 litres of hot water in that cylinder and once you have used it up, it takes about 3 hours for it to heat up again from the boiler.

If you have an electric immersion heat on your cylinder the recovery time is about 1-2 hour.

There not endless supplies of hot water.

If you need an endless supply of hot water, get a unvented hot cylinder there about £600 and will give you about 8 hours of mains pressure hot water.

[Dino]

Peter the plumber I'll explain again, from a cold immersion tank I turn the immersion on, after one hour it clicks off, I run the bath it has not delivered sufficient water for a full bath, ok ?, for the simple reason, it has not been on long enough to heat enough water for the bath. so I adjust the dial to a higher setting it still goes off after one hour and still doesnt deliver, I have had the dial on all the settings some clicking off below an hour the maximum time my immersion stays on is one hour it needs to stay on longer but the thermostat wont allow it, point of interest before I had this new immersion fitted I coulg get a full bath time and time again no problem whatsoever this just wont deliver enough hot water no matter what setting it is on, funny enough the first reply to my query from Martin or Marrtin is exactly what a sparks told me the length of the element is fitted wrong...Dino

[marrtin]

Take the thermostat out and measure it. It's in a tube so will slide out, but obviously needs disconnecting first so bear in mind mains electrics, frying, burnt flesh etc Lol. If it's only 8" long then measure the depth of the hole it came from needs to be about 18" for a 27" element.

[peter the plumber]

Why are you getting an electrician to have a look at a hot water cylinder?

Do you know this is the first time I have heard of anyone fitting the wrong element to a cylinder, all cylinders are supply with the right size element and there replaced “like for like.â€