Shower goes cold after a few minutes

[alig301]

Hi,
when running the shower which is fed direct from the combi boiler, the shower goes cold after a few minutes and will remain cold for another few minutes before gradually warming up again. The tap next to it will run hot water constantly as will the rest of the taps in the house. I have changed the shower mixer with a new one and still the same issue.

Anyone any ideas? I am stumped as to why it only happent to that shower.

Thanks in advance
Al

 

[Chuck]

Hi,
when running the shower which is fed direct from the combi boiler, the shower goes cold after a few minutes and will remain cold for another few minutes before gradually warming up again. The tap next to it will run hot water constantly as will the rest of the taps in the house. I have changed the shower mixer with a new one and still the same issue.

Anyone any ideas? I am stumped as to why it only happent to that shower.

Thanks in advance
Al

Which model of combi do you have? Which model of shower? How many litres of water per minute are you asking the shower to deliver (measure how long it takes to fill a 1 litre container)?

 

[alig301]

Which model of combi do you have? Which model of shower? How many litres of water per minute are you asking the shower to deliver (measure how long it takes to fill a 1 litre container)?

So the shower has been installed for a long time and the boiler has just been repaired with a fan fault. The shower is a Mira shower mixer bar but as I said it has been working fine up until now. Could it be something to do with the boiler though that is strange as there is another identical shower in the house which works fine and when the hot taps are run they run hot freely which would be more hot water than the shower

 

[John.g]

Did you say or does the shower still run cold with a hot tap close by still delivering HW at the same time?.

 

[alig301]

Did you say or does the shower still run cold with a hot tap close by still delivering HW at the same time?.

mmm not tried simultaneousl. But when I turn the shower off ond run the hot tap, it runs hot continuously.

 

[John.g]

Just try that, then try another test. (switch off hot tap)
Switch shower to its hottest setting and set the boiler DHW temp to its coldest, see if you get lukewarm water.