Hot water problem

[johnsom]

i have had a heatline vizo 24 condensing combination boiler fitted.
when i turn the hot water tap on full to fill a bath it goes cold when the tap is turned down to a dribble it turns hot again,
The only other hot water tap is in the kitchen 2 foot from the boiler but this tap is ok ????
Please help
Martin

 

[boxhead]

hi, believe it or not ive just put a thread on the central heating forum with the same problem plus others. im sick to death of mine and thin king of changing it. good luck

 

[rich250]

I would like mention that I think that the secondary heat exchanger is lime scaled up. You van either get a new one fitted or get it cleaned with lime scale remover. The best bet would be to replace it with a new one, if this is the case. But it does sound like it is.

 

[LIFES A GAS]

How many ltrs per min do you get from the kitchen tap? you should be able to get much the same flow rate at the same temp at the bath unless it a very long pipe run and looses lots of heat due to the length of pipes.
Martin

 

[xdavid]

I've just fixed my own, similar, problem by cleaning the hot water heat exchanger but my sink temperature was low too. My thread here... http://www.ukplumbersforums.co.uk/central-heating-forum/8004-dhw-getting-cooler.html

Are you sure that the water at the sink is not colder than it used to be? My sink is beside the boiler but I still had to reduce the flow rate to get a good temperature (compared to previously). The bath is a longer run away and, although pipework lagged, there was a noticeable difference in temperature (compared to sink) due to heat loss in between. So maybe the heat loss in the your pipework is high which is compounding your problem... high heat loss + low flow rate.

When you say "i have had a heatline vizo 24 condensing combination boiler fitted", do you mean recently? If it is new then I would think that the exchanger would be clean unless there was lots of gunk in your system which has quickly blocked it.

Disclaimer: I'm not a plumber! Just had a similar problem.