Temperature fluctuations in shower

[elie aoun]

Hoping someone can help!!!
We have a gas hot water service – brand new 6 months ago. We have no issues at any other point than the shower. Firstly it takes and enormous amount of time to find a consistant temperature. Then, without notice, the water will change from normal to boiling hot then freezing cold then back to normal or similar combinations. There are no other taps being used in the house – no toilet – no dishwasher – no other running water. No other water outlet does this. It is almost impossible to have even a short shower as you haveto keep getting in and out or risk burning. This may well be something simple but the plumber who last visited us thought it was in our heads or at least could not offer any suggestions. Is there something we can do or are we doomed to waste enormous amounts of water trying to just get clean??

[smorton000Participant]

What type of heater is this that we are talking about. It could be other things, but it sounds like the shower has a water saver shower rose installed and the heater dose not allow for a flame turn down far enough to keep it steady. Is the heater you have rated for a triple A shower rose. The Infinity will work on very low flow rates but other heaters will only work on higher flow rates,

[SelgasParticipant]

Yep I want to klnow what kind of water heater you have had fitted as well – is it a storage cylinder or an instananeous external gas type like a Bosch, Rinnai, Wallman, Rheem etc?
Each of the latter type of water heaters will only control temperatures accurately if there is greater than 4 litres of pure hot water passing through them – any less will cause the computer to regulate the temperature from hot to cold etc as it cannot fatham what is expected of it to control. If it is one of these kinds of water heater and you are using a flow rate of hot water greater than 4 litres per minute then check the shower rose or mixer as it is possible a jumper or valve component has worn and is allowing one water source to flow faster than the other when the shower in use. Let me know please.

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Selgas Services Ltd
Craftsman Gasfitters, Plumbers, Electrical Service Technicians

[micheleleanorParticipant]

Thanks to both for getting back to me. We have a Rinnai Infinity wallmounted small box gas hot water service and, yes, we also have the water saver shower head!!! We have been managing to avoid some of our issues by now running another tap will full hot water only as we set up the shower and running the shower as hard as possible. This has stopped the temperature issues but I am still concerned about the amount of water we are having to use to get there.
Either way, we seem doomed to be using more water than we want to.

[SelgasParticipant]

Yup such is the way of modern technology it seems – the problem you are experiencing can be due to very low actual hot water flow ( less than 4 litres minute ) as well as the low fire settings in the Rinnai Infinity which can be altered but should have been correctly set at the time it was installed. If the low gas pressure setting is incorrect ( over pressured ) then this fact can also give the same result. Have the unit’s pressures checked and reset to specifications you may find this eliminates your problem.

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Selgas Services Ltd
Craftsman Gasfitters, Plumbers, Electrical Service Technicians

[micheleleanorParticipant]

Thanks!
Would it also be worth trying a new shower head? We are in a rental property wth owners who do not like getting problems fixed. I think we are capable of changing a shower head ourselves without getting another visit from a plummer. Do you think this might help?
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