no hot water when bath running but rest of house ok?

[mark h]

anyone help! ive got a ferroli potimax he plus 31c combi, hot water is fine through sink downstairs and in bathroom running at 55degrees c, but when i run bath it wont go any higher than 34degrees c. plus im getting a whistleing sond when i run bath. help! been told i need to change bath valve as may be damaged thus causing pressure problems from boiler. is this correct?
been in touch with supplier they say its a plumbing prod. have noticed flow rate on tap has increased,could it be too fast for boiler to heat up water?

 

[Puddle]

If water only cool through bath,probably water flow rate to high,as bath taps allow greater flow rate if allowed,restrict flow rate slightly at boiler to improve temp at bath

If flow rate correct,after that it could be low gas rate due to incorrect adjustment or gas pipework undersized

Also it thermostatic shower above bath ,maybe getting a little cold water feed back through valve if non return valves not seated correct

imho

 

[mark h]

cheers m8, when i run hot bath tap on steady instead of full
it works fine,
only does it when tap turned up full.
seems to be flowing alot faster recently, could this be a tap problem

 

[Puddle]

cheers m8, when i run hot bath tap on steady instead of full
it works fine,
only does it when tap turned up full.
seems to be flowing alot faster recently, could this be a tap problem

If that the case,just restrict flow at boiler as said

Maybe water pressure/flow has been increased in your area

Water board may have repaired a few of their leaks in the mains in the streets !!

 

[mark h]

thanx 4 help mate, one last thing how do you restrict flow on boiler.?

 

[Puddle]

thanx 4 help mate, one last thing how do you restrict flow on boiler.?

There should be a isolation valve on the cold mains into the boiler,close this slightly

 

[mark h]

awesome!!!!! thnx m8

 

[aggis]

If the water pressure is really high restricting the flow at the boiler will slightly improve the temp, but it doesn't alter the pressure which does the damage.Fit a pressure reducing valve on your cold supply to the house & set up to about 2- 2.5 bar. will protect all your taps & appliances. Pressure & fow rate are 2 different things, they both need to be right to get the correct performance ie temp & flow rate. A 31kw boiler should give approx 35c temp rise from cold with a flow rate of 11- 12 litres / minute.

 

[stevetheplumber]

dont turn the tap on full would seem to be the answer tap is flowing more water than the boiler can produce

 

[Plumbstar Tom]

or fit a flow limiter to the taps inlet