Hot Water Supply Subsides After Short Use

[Groovycat]

Hi Forum

We have a Worcester Heatslave 9.24 bf.

I have read as many posts as I can on this, and other websites, about this problem, and though not exactly the same as others, held my suspicion at the diverter....

When I turn on the hot water with a medium flow (vague I know), and after the usual delay of a few seconds while the exchangers do their bit, hot water begins to flow - slowly increasing in temperature. After roughly a minute, the temperature begins to drop until it runs cold again.

Suspicious of a faulty diverter I watched what it did when repeating the above: again, after a minute or so the boiler stopped firing and very shortly

afterwards the switch plunger from the diverter receded. When the tap was turned to almost maximum flow, the plunger activated the switch once again and the boiler fired. This time it remained lit for several minutes before the plunger receded only very slightly (enough to stop the boiler firing again). I touched the plunger very gently which activated the boiler again, and once released the boiler stopped.

What do you think? The diverter?

Thanks

Groovy.

 

[Agile]

Many taps reduce the flow as they get hot !

I suspect that your diverter valve is failing and requiring more than 2.5 li/min to operate it.

The thing to do is to MEASURE the flow rate at which the pin comes out!

Tony

 

[gas4you]

If its doing it only on one hot tap, replace the tap washer first, to eliminate the obvious, cheapest and simplest.

Old worn tap washers can swell with the hot water.

If its on all taps, then get Worcester in on their fixed price repair scheme.

 

[Groovycat]

It happens when any hot tap is used.

Forgot to mention that I also noticed some white 'stuff' around some of the connections to the diverter as well as a small amount around the hole where the plunger comes out. The white stuff looks very dry and quite foam like, with verdigris where it attaches to the pipe.

Could a faulty flow sensor contribute to the problem I describe?

Thanks again forum.