repair combi boiler or install thermostatic shower??

[miss_dunn]

Looking to install a new shower... at the moment we have a manual mixer shower running off a combi boiler which works well providing the radiators are on or have been on very recently... if not then the hot water runs from the shower fine for around 5 minutes, then the shower goes completely cold for approx 1 minute, then back on again. This pattern will repeat itself every few minutes and gets very frustrating!

Is this likely to be a problem with the combi or is this the very reason that thermostatic mixer showers were invented?

 

[ChrisR]

A thermostatic shower will not heat the water up!

Problem you describe has been on the forum half a dozen times in the last few days. Dirt in the secondary (the tap water) heat exchanger, boiler side. H/ex will need to be cleaned or replaced

 

[miss_dunn]

Legend. Ta!