Cold/Hot water issue in flat

[HeavyD16]

Good day,

We have a continous water issue that I was hoping to get some advice on.

When using hot water in our flat, it takes a long time to heat up, then gets pretty hot irrespective of temperature setting, then gradually loses pressure. Then the pressure suddenly kicks back in but the water then goes icy cold before gradually warming up again and the cycle repeats - it is normally hot for 1-2 minutes before going cold for 1-2 minutes. You can see how this is an issue when showering in the middle of winter....
This has been happening since pretty much when we moved in about 9 months ago.

We had BG come over to look at the boiler and say they can't find anything wrong (there is a homecare contract in place with BG) A plumber came in and said it had something to do with shower mixers and it would be a major repair job blah blah which I don't believe since the issue is everywhere not just at the showers (and is exactly the same across both showers in the house)

We are leasing the flat and have a meeting with landlord to discuss and would like to have some theories as to what is wrong. Can anyone give us some possible things to look out for?

Thanks!

 

[Agile]

You have not bothered to tell us the boiler make and model.

In that case its worthless guessing at whats wrong.

Even with that info unless there are common faults all we could do is guess.

As you say it has that fault then why did BG not see it happening?

Tony

 

[HeavyD16]

Apologies

The boiler is a Worcester 35CDi combi boiler. The boiler is housed in a pretty narrow cupboard in the kitchen- all the dials and the gauge are there to be seen, but I can't really look around/under the unit

I realize it's a guess without actually looking at the situation - however what I'm looking for it a couple of possibilities that I could then raise for further investigation. I will admit I am not knowledgeable when it comes to plumbing which doesn't help.

BG claimed there was nothing wrong with the boiler and was an issue outside their contract (I am new to the UK and also don't own the flat so no idea what the contract actually covers). They recognised the problem but simply said they had no idea what caused it.
To be fair this was also some time ago when the issue was less consistent than it is now. We've lived with it up till now but it will become a bigger issue again as winter approaches...

 

[OwainDIYer]

does this happen with all taps, or just the shower?

some shower mixers don't play nicely with combi boilers - showers often reduce the hot flow to reduce the temp, but on many boilers reducing the flow increases the temp, so the two temp control mechanisms end up fighting each other.

Or the shower temp regulating cartridge might have failed.

 

[HeavyD16]

Happens with all taps, most noticeable with shower since you don't often run hot water for longer than a minute or so anywhere else.