Shower temperature fluctuations

[Pontycanna]

I wonder if anyone can be of assistance.

I have recently bought a Marflow Consort C72 (concealed) and had it installed by a plumber. Unfortunately the house was still being developed and the shower unit had not arrived therefore I did not use the shower until about 2 weeks ago.

After approximately 1 minute I will get hot water running from the shower, however this will only last for approximately 45 seconds – 1 minute. The shower then goes back to only emitting cold water for 2-3 minutes then it will eventually go back to warm water again for a short period.

In the periods that the shower is only giving out cold water any adjustments to the shower lever / thermostat makes no difference to the water temperature at all.

I am running the shower from a combi bolier, is this a problem anyone else has experienced or has knowledge of?

Problems I have considered / thought about are:

Cold water pressure too high? (is it running directly from the mains?)

Broken thermostatic valve (I think that this is unlikely due to the age of the unit – 2 months)

Flow rate that the shower is demanding is too much for the boiler to handle?

Could it be that the plumber has installed the unit (thermostatic valve) the wrong way around? The thermostatic valve would then be struggling to regulate the temperature? (He did struggle at the time to put the lever of the unit on the right way and therefore ended up fiting the handle upside down, I thought this strange at the time but didn't really worry as long as it worked - I am now regretting that decision)

I have contacted the plumber who has been of no help and blamed the problem on "at certian times of the day if everyone in the street is washing/placing a demand on the water supply to the street, the water pressure will drop and effect the supply to the shower - there is not much you can do about it"

If you could throw some light or suggest any possible solutions it would be much appreciated.

 

[Dan Robinson]

What make and model boiler do you have?

It does sound like the plumber has insallted it upside down although the cartridge could be iffy.

If your have a non modulating combi then that would also explain it.

 

[ChrisR]

Thermostatic sHowers with hot and cold reversed only ever, afaik, give only hot or only cold water, so that doesn't sound like your problem.

As above, I'd want to know about the boiler cos sludge in that is usually the culprit.

 

[Dan Robinson]

I fitted an aquavalve a few years ago. Got myself muddled as working in too rooms and running out of time and got the hot and colds mixed up. Thing owrked fine for months then the customer reported all sorts of strange temperature fluctuations.

Was a little embarassing but thanks to my prolific use of bulldog valves it too mere minutes to get sorted.

 

[kev25v6]

Turn your shower on and watch the flame in your boiler, my shower kept running hot then cold and it was the boiler cutting out due to it over heating. Needed a new thermostat, gas valve and thermocouple in the end to sort it. Also is the shower a thermostatic one?

 

[Dan Robinson]

Idiot.