Hot Water Problem - Help Please!

[eeyore]

I have a Worcester 24i RSF Combination boiler, used for central heating and hot water.

I am finding that it is taking several attempts of turning the hot tap on and off before the boiler starts to heat the water. I can hear that it has registered the demand for hot water and the fan starts up, but no heat. It doesn't matter how long the water is run for, the heat never kicks in.

The only solution is to turn off the tap, wait a few moments and then try again. Sometimes, jogging the tap quickly up and down a few times before opening fully seems to work - you can hear a valve 'clicking'. Eventually, after a few goes, it ignites and the hot water is then continuous and problem free for as long as it is running.

I have found that this is usually only a problem during the summer when the central heating is off. In winter, when the heating is generally on, there are no problems obtaining hot water. We had the heating on the other day to help dry out our newly washed carpet, and the hot water was fine. However, the problem seems to have been particularly bad this summer.

Does anyone have any idea what the problem might be? Is it likely to be expensive to fix?

Many thanks in anticipation.

 

[gas4you]

If the fan is running then it must have recognised the DHW demand, so I would go for the air pressure switch not proving the fan. This could be the clicking you here.

I assume you mean the fan is starting everytime?

 

[eeyore]

I assume you mean the fan is starting everytime?

That's right.

What do you mean by "not proving the fan"?

The clicking is while I rapidly turn the hot water tap on and off - it's obviously actuating a valve of some sort and I assume that is normal?

What does the air pressure switch do?

 

[gas4you]

This tells the boiler pcb that the fan is running and safe to continue to the next stage of ignition.

 

[eeyore]

Is an air pressure switch expensive to replace?

 

[gas4you]

Yes if it hasn't been diagnosed correctly and wasn't this that was at fault

I dont know these boilers too well, but would say that it is one of the few bits on these that can be changed reasonably easy.

 

[Agile]

I think this is the model which sometimes gets water into the tubes or even the switch itself.

It MIGHT just be moisture in the tubes.

Tony

 

[Gasguru]

Strange how it appears to work OK for central heating although an intermittent APS can be hidden on heating since users don't notice the heating if it only fires up every few goes.

The APS is just under £20.00 and sooner or later it will need one so may be worth swapping on the off chance. 5 minute job.

P/No 87161424140