I have just moved into my new house and have a question re the combi boiler. For hot water i run the tap in the kitchen and I have boiling hot water instantly. It then cools down and takes an eternity to warm up again. it seems the only way to get hot water is to run the tap slowly (hardly open) for a while and i get consistently hot water. My question, is this normal or does it sound like a fault? Should i get constant hot water as soon as the tap is opened?

cheers in advance for any replies:thumb:

the hot water u first draw off is what is sitting in the heat exchanger, if you have had no central heating on (basically boiler cold) then you will find it will still take the same time to heat up.
what make of boiler is it? has it been serviced?
simple things like burner pressure can effect hot water delivery ie burner is not burning hot enough to heat a larger volume of water hence having to reduce the flow thru the taps.
without knowing what make of boiler it is i cant say if there are common faults like sensors etc as they all work differently

Its a 'swiftflow gloworm' boiler mate. I also find I have to prime the pressure a lot with a tap under the sink.

Thats sounds opposite to my combi, I loose temp when running a low flow & it takes ages to get back up to temp after its gone cold even when I turn tap on full.

Is the CH on at the same time?

I'm having similar probs at the moment and my first investigations are that the diverter valve is sticking in the CH position and not letting the heated water into the secondary heat exchanger when the hot tap is turned on....see UK.DIY Combination Boilers (http://www.diyfaq.org.uk/plumbing/combi.html)

The pipes from the boiler to your tap wont be insulated and will cool down quickly after the taps have been used and when the boiler has delivered hot water and switched off for 5 or 10 minutes it will not deliver instant hot water until the boiler internals have heated up again,but this will not be the case if the heating is on.The length of pipe from the boiler to the tap is another factor.Not very water efficient combis

Evening i dont know what model swiftflow you have but they all use a cross flow heat exchanger ie no diverter valve or plate exchanger:your boiler should raise incoming cold water 35 degrees at a specific flow rate of 12 litres a minute use a wier guage to accurately measure or other wise it should take approx 5.5 seconds to fill a litre container of water.Your burner pressure sould read 15.8mbar or 6.3 in wg. if you obtain these readings your boiler seems ok: remember you usually have to run a dead leg of water off in order to get your main hot water supply.
By the way if you can not obtain your 35 deg temp rise your heat exchangers probably blocked or scaled depending on your water hardness.hope this helps......Mal