Shower not reaching set temperature

[MarkWilliams363]

So to cut a long story short (ish) my old electric shower Triton Madrid was playing up. The shower its self was 10 years old so I decided to just replace it with a like for like equlivant Triton Cara.

The issue I have is that the shower does not heat up to the desired temperature unless i turn on the Basin or bath tap for around 5 seconds. (bath/basin and shower all off the same main cold water feed)

I complained to Triton and they sent an person out to investigate. unfortunately I was not home at the time and my Mum waited for the engineer. From what Ive been informed he turned on the shower and said the pressure seemed low. He then turned off the shower and turned on the cold water tap in the sink and said the pressure was too low and that was the problem. (the isolation valve is turned down as the pressure is too high and the water spills over the sink)

He then went and checked the stop cock which unfortunately was jammed solid and suggested that this may be the issue also.

since then I have changed the stop cock into the house, the basin taps, bath taps & isolation valves and also the isolation valve to the shower yet the problem still exsists, I have tuned off the mains and attempted to flush the sysem to rid of any air locks yet the issue still exsists.

Turning the basin or bath tap on briefly and off with the shower running seems the only way to get the shower upto temperature.

Any advice greatly appreciated.

 

[jj4091]

Did it happen with the old one. Does the low pressure indicator illuminate. Did changing the stop cock and isolators improve the pressure at the taps.

 

[CountryFan]

The only way to measure pressure accurately is with a gauge, not by sight. If you’re turning other taps on this reduces the working pressure slightly and certainly the litres per minute of flow rate. Perhaps now you’ve changed these call Triton out again? Failing this, if still under warranty return for a replacement/change brand?

 

[MarkWilliams363]

Did it happen with the old one. Does the low pressure indicator illuminate. Did changing the stop cock and isolators improve the pressure at the taps.

Hi, No it didn't happen with the old shower. And no lower pressure warnings showing. The things I have changed has not made any difference to the pressure at the taps from what I can see. Saying that the pressure from the taps (basin & bath) is plentiful enough, good pressure.

 

[MarkWilliams363]

The only way to measure pressure accurately is with a gauge, not by sight. If you’re turning other taps on this reduces the working pressure slightly and certainly the litres per minute of flow rate. Perhaps now you’ve changed these call Triton out again? Failing this, if still under warranty return for a replacement/change brand?

The issue with that is Triton will charge £150 if the issue is found not to be with the shower, which sadly is something which I cannot afford. The shower was supplied brand new directly from themselves.

Could an air block be causing the issue? As the pressure on both taps (same feed) is plentiful

 

[Johntheo5]

All electric showers even when working perfectly well take ~ 12 to 25 seconds to reach their operating temperature, they also require a flowrate of ~ 3.5 to 5 LPM to close the pressure switch to send power to the heating elements, suggest getting a container, hold it under the shower with the shower head in its normal position, in the holder, after exactly 30 secs remove the container and measure the flow rate via a 1 litre container, x 2 to give the flowrate in LPM, then turn the temperature control to fully cold and repeat the test. From a now mains temp of 15C a elect shower will provide 1*860/60/(40-15), 0.5733LPM (@ 40C) per kW, so a 9kW shower like mine will provide 0.5733*9.0, 5.16LPM etc. at 40C.

 

[MarkWilliams363]

So I've done the following. (with shower head attached)

1. At temperature 6 (first hottest, temperature I like to shower with) took 10 seconds for 1 ltr. (heated up to temperature)

2. Coldest setting took 7 seconds for 1 ltr.

3. At 6 took 10 seconds (did not heat up)

4. Bath tap (same feed) >4 seconds 1 ltr.

5. Hottest temp. Took 21 seconds. The water flow spluttered. Water went red hot.

6. Coldest setting 7 seconds 1 ltr.

7. Temp 6 10 seconds 1 ltr (got to temperature)

8. Max temp took 24 seconds. Water flow spluttered again. Water went red hot and then cold.

 

[Johntheo5]

1 is 6.0LPM no problem, a 8.5kW shower will have a flow temp of 35.3C.
2 is max flow of 8.57LPM, quite normal.
3 is (again) 6.0LPM, no reason for not heating up.
5 is 2.86LPM, the thermal cut out, TCO, operates at 48C, a 8.5kW shower will potentially have a flow temp of 57.6C at 2.86LPM so the TCO operated correctly to switch off the power to the elements.
6 is again a max flow of 8.57LPM, quite normal.
7. is again 6.0LPM, no problem 8.5kW shower gives a flow temp of 35.3C, as in 1 above
8 as in 5, above.

Some Triton showers had trouble with TCO not resetting after a (hot) 48C trip, every time you switch off the shower then the TCO operates about 10/12 secs later, you will clearly hear it "Clicking".
Suggest running the shower at minumm flow again, it will then run very hot, then quite cold (15C), then very hot again, (if the TCO resets), which it should after maybe 10/15 secs or so, if its taking longer than say 1.5/2 minutes then a problem with the TCO.

Can you post the Shower Power Output, ie 8.5kW or whatever

 

[MarkWilliams363]

I'll give that a go thanks.
Its an 8.5kw shower.

 

[Johntheo5]

OK. I've edited the above to reflect this.

 

[MarkWilliams363]

Turned the shower on whilst it was on temp 6 took about 40 seconds to heat up.

Turned the temperature upto maximum.
Went red hot and then back to cold.
Took around 30 to 40 seconds to heat back up to maximum temperature. Funnily enough when starting to heat back up the flow started spluttering. Whilst cold the flow was fine. Went through the same thing 3 times.

 

[Johntheo5]

Well, ostensibly, nothing wrong with the TCO, I just tried my own (9.0kW) Triton T80Z, at max temperature and it behaved similarly to yours, the pressure switch always turns the power on to the elements but at those sort of flowrates, I cannot see this being a problem, there is a low pressure flag on my shower but don't see any on yours?.

Does the power on indicator light flicker on/off, I have seen something a bit like your problem but it was the contacts on the pull cord switch, problem disappeared when I renewed the switch.

 

[MarkWilliams363]

So Turned on the shower on coldest setting then turned to 6. Took 80 seconds to start to heat up at which point there was a spluttering with the water.

Turned to maximum and again as before water spluttered then went redhot for a short duration and then cold again as before.

No flickering from power indicator on the shower or the switch (please see photo)

 

[Johntheo5]

I don't think its your isolator, especially a wall mounted one, it does look like the TCO as it should not take 80 seconds to start heating up, as a temporary measure would suggest, when showering finished, turn the power selector to cold but let water flow through the shower for say 20 secs or so before switching off, this will ensure that the TCO doesn't operate after every shower, (turn the power selector switch back on before exiting the bathroom) if there is then still a big delay in commencing to heat then some problem with the pressure switch or the flow stabilising valve, can't think of much else.

 

[CountryFan]

If it’s spluttering then that would suggest a possible air lock, in which case tco would operate and could take a while to heat up