Inconsistent Hot Water

[jagemail]

Hi,

I have a combination boiler system with boiler at ground level. The water pressure in the hosue is fairly good However in the last 2/3 months it seems like the system has developed a problem. The temperature of hot water from the tap in bathroom on the first level is very inconsistent. Usually it will give hot water for 10-20 sec and then cold througout. but if you keep turning the tap off\on\off\on once in ten times it will give consistently hot water. the hot water from kitchen tap on ground floor seems to be fine all the time. One more thing - the boiler does light up while the hot water tap in the bathroom upstairs is throwing cold water.

Is this a sign of a failing boiler? it is about 12 years old now.

Is my best bet to replace the whole thing? or is there an obvious fix?

Thanks

J Mann

[Hugh]

One simple thing to try is to put the central heating on - do you then get hot water from the bath tap? If so it a strong indication that the diaphragm in the diverter valve needs replacing. It's a do-able d-i-y job - £10 - £15 for parts - you must replace washers and 'o' rings and use silicon lubricant. It's sometimes better to replace the whole valve although a lot more expensive - typically £70+ for the part.

12 years isn't old for a boiler (IMO) Report back if not the problem!!

Hugh

[John Rumm]

Well, assuming the boiler carries on firing in this circumstnace and does not shut down with an overheat fault, then the heat must be going somewhere. Ths obvious conclusion would be the central heating. This could indicate that the diversion valve (assuming the boiler has one (most do)) is failing.

Nope, just a failing part.

Scale in the secondary heat exchanger can also reduce hot water performance as the boiler ages.

Seems a bit drastic, and "probably" ;-)