Hot tap running cold when fully turned on

[vibrobullit407]

I have noticed that when I run a bath I have to turn the hot tap down as it seems my boiler can not cope with the flow. I've never noticed it before I changed my bath taps. Is this a problem with my boiler or is it a problem as I have been told by a "plumber" just the flow rate?

My boiler is a Vaillant Turbomax 824 Plus. It was fitted in 2002 so getting on a bit but surely there must be plenty more life in the old girl. Apart from changing the diverter valve twice and more recently the PCB (due to leak above), I have had no real problems.

Any help will be appriciated

 

[cantaloup63]

New bath taps. Increased flow rate. Chances are that the boiler hasnt degraded overnight and it's just the taps coupled with the incoming supply being a lot colder anyway.

 

[doitall]

Too much flow, or a backfeed from the cold.

Did the plumber connect the taps in 22mm pipe or 15mm

 

[vibrobullit407]

I'm in the stages of doing the bathroom my self. The supplies are ran in 15mm then step up via a 15mm - 22mm flexi to the bar mixer tap (Bristan Quadrato bath filler). I have not yet connected the cold as I have yet to tile the floor, meaning I have not removed the existing toilet due to having only 1. The toilet will be coming out tomorrow and the cold will be connected then. I have not changed the pipe sizes they have always been 15mm but I have renewed some lengths to make them a bit neater when finished (using compression fittings). If anything the lengths have been shortened. The bath is less than 3 meters from the boiler so not a very long run for the hot.

Is the fact that the cold is not connected causing a problem? I connected the hot so that I can use the bath while the work is being carried out.

 

[vibrobullit407]

Any more info from any body?