Hot bath water not as hot as downstairs tap?

[uptown47]

I'm clueless when it comes to boilers so I'm just going to ask this question using language I understand. I apologise now if I show my ignorance!

I have a good combi boiler (Baxi Platinum). The guy who installed it a couple of years ago put in a bigger diameter gas pipe to feed it. It bought it because our previous boiler struggled to get the bath water hot enough without putting the tap on a dribble.

This boiler seemed to be coping well but I've noticed over the last couple of weeks that the bath water hasn't been as hot. If I turn the tap down when filling the bath it sometimes just goes to cold water - I'm not sure if there needs to be a certain amount of flow to get the boiler to kick in??

The hot water temp is set to 58 deg and is plenty hot enough at the kitchen tap downstairs so I didn't want to just turn the temperature of the hot water up?

I wondered if anyone had any ideas what the issue could be? Could it be because the radiators are on at the same time as the bath is trying to fill? Or could it be something else?

Any advice / help that could help?

Thanks

 

[Madrab]

2 things probably effecting it.

1) bath flows more water than the sink tap therefore the boiler has to work harder to keep the temp higher and it been fine right up until the winter
2) cold water now much colder (>10deg colder) entering the house, therefore the boiler is now struggling to maintain the higher bath flow at the same temp.

All dependent on the boiler size too.

 

[uptown47]

Thanks for getting back to me Rob.

Do you know why, if I turn the pressure down on the bath tap, then it suddenly runs cold for a while?

Also, is it worth upp'ing the hot water temp beyond 58 deg? Or would it either (a) not make a difference or (b) potentially damage the boiler/pipework or whatever?

Thanks for your help

PS. the boiler is 40KW

 

[Madrab]

You can turn the boiler up to its max, usually 60Deg, no issue there.

When you say "turn the pressure down", do you mean close the tap a bit? Turning down the tap may be shutting the boiler off for a sec and then it fires back up, get someone to check the boiler when you do it.

 

[uptown47]

You can turn the boiler up to its max, usually 60Deg, no issue there.

When you say "turn the pressure down", do you mean close the tap a bit? Turning down the tap may be shutting the boiler off for a sec and then it fires back up, get someone to check the boiler when you do it.

Yep, I mean turn the tap down a bit. It must be shutting the boiler off I reckon. I'll turn the temp up and then maybe do some testing with the heating on/off.

I appreciate your expertise on this. Thanks for all your help