Hot water tank not keeping heat

Ectophile

Maybe the thermostat on the immersion is set too low. Most have a thermostat built in, hidden under a cover.

Make sure that the power to the immersion is off, or you could electrocute yourself. Undo the nut or screw holding on the cover of the immersion. See if there's a little dial underneath.

It should be set to at least 55C. 60C is recommended. Anything less than 55C risks getting Legionnaires disease.

theoretica

I would set the clock to the wrong time so the 3 am turn on will happen at a civilised time and see if it does heat up the water at all/how much.  Then you would know if it is those pegs on the timer or something on the element.

Are you a hard or soft water area?

Bendy_House

My concerns about the 'pegs' are that if it's half-activating the switch, there could be a dodgy connection and even some contact scorching going on - so the immersion is not getting full power.

These pegs could well be normal for that timer, but they sure do look 'wrong' for every one I've ever seen!

FB, when doing manual tests on powering the immersion, could you use the 'on/auto' switch on the side, and not these pegs? Tobesure tobesure.

ForestBluebells

I’ve got it set to “on” now using the pegs and turning the dial to that time. Will report back in an hour if that gets the water hot. If not I’ll try the “on” switch on the side

NSG666

How many days was it between you adjusting the timer for the new tariff and the water not getting hot?

YellowCarBlueCar

As a completely different suggestion, does your hot water pipe run through a concrete floor?

My dad's 1970s bungalow had a hot water pipe spring a leak under the floor, and the only way he found out was that the hot water was behaving in the way you describe.

If you're on a water meter, the easiest way to check would be to check the meter when you're not using any water (and tanks & cisterns aren't refilling).  If not you may need to look for header tanks slowly filling after a period of not using any taps.

ForestBluebells

It’s been “on” over an hour and I’m not sure if it’s got much/any hotter. I’d still shower with the water that temperature on the hot tap alone…. So either the buttons are not down properly or the temperature is set wrong. I’ll leave it a bit longer and see if it still heats more otherwise I’ll try the “on” switch on the side

ForestBluebells

YellowCarBlueCar said:

As a completely different suggestion, does your hot water pipe run through a concrete floor?

My dad's 1970s bungalow had a hot water pipe spring a leak under the floor, and the only way he found out was that the hot water was behaving in the way you describe.

If you're on a water meter, the easiest way to check would be to check the meter when you're not using any water (and tanks & cisterns aren't refilling).  If not you may need to look for header tanks slowly filling after a period of not using any taps.

Absolutely no idea, I have suspended wood floors but never looked underneath as I don’t have access without ripping the floor up. Will check the water meter but I took a meter reading recently and it was less than estimated so if leaking it’s very slow

YellowCarBlueCar

ForestBluebells said:

YellowCarBlueCar said:

As a completely different suggestion, does your hot water pipe run through a concrete floor?

My dad's 1970s bungalow had a hot water pipe spring a leak under the floor, and the only way he found out was that the hot water was behaving in the way you describe.

If you're on a water meter, the easiest way to check would be to check the meter when you're not using any water (and tanks & cisterns aren't refilling).  If not you may need to look for header tanks slowly filling after a period of not using any taps.

Absolutely no idea, I have suspended wood floors but never looked underneath as I don’t have access without ripping the floor up. Will check the water meter but I took a meter reading recently and it was less than estimated so if leaking it’s very slow

OK - so probably not that - if you have suspended floors then I'd have thought a leak would be pretty obvious.  In dad's cases the pipe in question was set in the concrete slab, so when it sprang a leak the water was escaping into the ground below, with no signs inside.

Bendy_House

ForestBluebells said:

I’ll leave it a bit longer and see if it still heats more otherwise I’ll try the “on” switch on the side

Cool. That'll be interesting.