Our shower has stopped working: did switching our thermostat off while away affect it?

MothballsWallet

We're having an issue with our 1990s-era Triton T80i electric shower where it's dripping from the shower head and we can't get hot water late at night.

We have a Hive smart thermostat system which was installed in 2016 with a new boiler: this is set up to heat water twice a day for 30 minutes each time.

We had to be away from home last month due to a family emergency and I thought I was being clever by changing the settings on the Hive to "frost protection" (below 11.5 degrees C) for the heating system and switching off the hot water schedule because there would have been no point in heating water while we were away.

After returning home, I changed the Hive settings back to what they were before we left, so the hot water is back on twice a day and the heating system is back to 16.5 degrees C, then when we tried using the shower late at night (after 10 pm), it was not heating the water - the power light never goes on, but it does work if we use it earlier in the day.

We were away during the heatwaves, so could those temperatures have done something?

We're still getting hot water from the taps in the kitchen sink, bathroom sink and bath, but we'll check those again tonight when we perform another test (which I'll film on my phone).

The shower is fed from a pipe leading to the attic/loft that has its own stop tap on it, but I'm not sure if it goes to the cold water tank or another hot water tank.

We've spoken to a local plumber who says what we did with the Hive shouldn't have affected the shower, and recommended replacing the shower, but what we'd like to know is has my changing the Hive thermostat settings done caused the shower to stop working properly? And would replacing it fix the problems?

Please let me know if you need any more information - I should be able to share the video via my YouTube account if needed.

MattMattMattUK

It is a cold water feed shower, it heats the water in the unit, the fact that it does not work at a particular time makes no sense unless there are other issues. Does the pump still work, or does turning it on just result in water flowing through it but not being pumped through?

Exodi

It's an electric shower, so generally it works only off the mains (cold) water supply and heats it on demand. Looking at the manual for the T80i also confirms this. You have somewhat confirmed this also by mentioning a single supply pipe (it wouldn't only get supply from the hot water tank else you'd be boiling yourself alive in the shower) as opposed to two supply lines for hot and cold water.

Likely to be total coincidence with regards to the changing of the thermostat settings or hot water schedule. Could be that the thermostatic valve has failed or the heating element - I replaced my shower this year for the same reason, though as it was also fed by hot water from the cylinder, I had the opposite problem that my water was scalding hot instead of freezing cold!

Likewise the easy check to see if your cylinder has hot water in it would be running any hot tap in the house for a short while.

It's good you have a stop tap on your shower supply, makes it easier to change in the event you replace the shower.

sheenas

My mums t80 failed recently in exactly the
same way. Cold water and no light.

WIAWSNB

As said above, that is an 'instant' electric shower, and works off your cold incoming mains supply. It should have nothing to do with your Hive, or stored hot water. 

You say you can't get hot water 'late at night', so it does work at other times? If so, that suggests the incoming mains pressure drops at that time for some reason. (Tbh, I'd expect the pressure to be higher late and overnight, as there's less use elsewhere, but hey).

Does the Triton have a 'low pressure' warning light? 

Even when it doesn't heat the water, it does still come on? Water does spray out the shower head? Do you notice if this is with less force at these non-heating times?

Does it have an 'on' indicator light? Is it steady, or does it flicker? 

Albermarle

We're having an issue with our 1990s-era Triton T80i electric shower

If it is 30 years old, then probably time for a new one.

FreeBear

WIAWSNB said: You say you can't get hot water 'late at night', so it does work at other times? If so, that suggests the incoming mains pressure drops at that time for some reason. (Tbh, I'd expect the pressure to be higher late and overnight, as there's less use elsewhere, but hey).

If the water pressure drops, I would have expected the temperature to increase - Used to have a cheap electric shower here that would always run hot due to the fact that we have low water pressure & flow rates. It got replaced with a Triton T80z Thermostatic. Although it was twice the price of a bog standard non-thermostatic, it was well worth it (Screwfix currently have the T80z for £177).

Exodi

FreeBear said:

WIAWSNB said: You say you can't get hot water 'late at night', so it does work at other times? If so, that suggests the incoming mains pressure drops at that time for some reason. (Tbh, I'd expect the pressure to be higher late and overnight, as there's less use elsewhere, but hey).

If the water pressure drops, I would have expected the temperature to increase - Used to have a cheap electric shower here that would always run hot due to the fact that we have low water pressure & flow rates. It got replaced with a Triton T80z Thermostatic. Although it was twice the price of a bog standard non-thermostatic, it was well worth it (Screwfix currently have the T80z for £177).

Is it as simple as imagining that lower water pressure = lower flow rate, meaning as the water is moving through the shower slower, it's in contact with the heating element for longer?

Whereas a higher pressure would be blasting out with less contact time with the heating element?

WIAWSNB

Exodi said:

FreeBear said:

WIAWSNB said: You say you can't get hot water 'late at night', so it does work at other times? If so, that suggests the incoming mains pressure drops at that time for some reason. (Tbh, I'd expect the pressure to be higher late and overnight, as there's less use elsewhere, but hey).

If the water pressure drops, I would have expected the temperature to increase - Used to have a cheap electric shower here that would always run hot due to the fact that we have low water pressure & flow rates. It got replaced with a Triton T80z Thermostatic. Although it was twice the price of a bog standard non-thermostatic, it was well worth it (Screwfix currently have the T80z for £177).

Is it as simple as imagining that lower water pressure = lower flow rate, meaning as the water is moving through the shower slower, it's in contact with the heating element for longer?

Whereas a higher pressure would be blasting out with less contact time with the heating element?

That is, indeed, how these instant showers adjust their temp - they tend to have two heating elements to provide a more crude level of control, but ultimate temp adjustment is by altering the flow rate through it - the temp control is a 'tap'. 

Some may be more complex, but that's generally it.

If the incoming flow rate falls excessively, the shower will just shut its heating off - it has a pressure switch to turn on the elements when it detects it has enough flow. So, a serious drop in mains pressure could give the symptoms described.

I missed the age of the shower! As Albe says, surely time for a new one? 

MothballsWallet

Thank you to everyone so far - I'm reading your answers and making a note of the questions that I'll try to answer later along with some video footage to show the daytime and night time differences.

Our water company is working on repairing a pressure problem about 5-10 minutes walk from our house, and that's been going on for a while now - I'm not sure if that might have something to do with it and I can't see when the issue was reported on their website but I know they're still working to fix it.

WIAWSNB

If you place a jug under your cold kitchen tap, turn it on full for 10 seconds, count the litres that came out and 'times' it by 6, you'll get 'litres per minute' - your flow rate. 

Try it again when your shower refuses to work.