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Worcester 24i combi boiler, intermittant problem help req

Postby silky951 » Thu Mar 03, 2011 9:21 pm

we have a wrocester 24i combi, i think its about 8 years old. we have it service every year by BG and had them out several times for odds and soods.

This problem started around 5 years ago but the problem only happened maybe 2 or 3 times a year, now though its happening around 2 or 3 times per week.


Ok, as you see in the picture a combi boiler.

Bottom right, the pressure clock, next to that the timer swtich with the on /off and timer button. next to that on the left is the heat control switch, you turn in for the hotness of the water.

Ok, the problem.

There is a switch on the timer, on, off and time setting (like a clock you can set it to go on and off at a certain time) We use the switch to turn the appliance on and off, we never use the timer as we only have heating either on all day or off.

ok, to swtich the combi on the switch is set to the bottom, on doing this the appliance fan goes on, this is a noice hard to describe but the fan comes on, after a few seconds the appliance ignites, you can hear this noise like a 'whoosh' gas igniting kind of noise. Then obviously the radiators get hot and we have hot water.

We have noticed that several times a week, that some times we feel a little cold and feel the radiators and they are cold, the appliance has gone off, so i go upstairs to the boiler and the fan is still going but obviously not working the, lets call it the ignitor as i do not know technical names. So now i can run the hot tap and only cold water comes out, the hot is now not working. The only way to get things back to normal is by turning the boiler off, waiting 5 minutes until the fan dies then return it back to on, and again the fan starts, then a few seconds later the appliance ignites and again we have hot water and the cenral heating is working.

This is an intermittent problem, it happens about 2 or 3 times a week, some days its ok, heating on all day and no probes, but another day the heating can be on from 9am in a morning then sometime on the evening the rooms get cold and we find the heating if off.

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Simply Build It

Postby Gas_man » Thu Mar 10, 2011 5:59 pm

by the look of it, the system pressure is zero. This will cause your appliance to overheat, and then shut down for heating.

You need to increase the system pressure to between 1 and 2 bar.

Incidently, the temperature control know, controls the heating temp, NOT the hot water temp. The hot water temp is preset in a 24i and cannot be adjusted by the user.

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Postby nclair » Sat Mar 26, 2011 3:39 pm

I have exactly the same problem with the same boiler! It doesn't happen all the time. Sometimes the boiler will go for weeks and work perfectly. Other times it can happen 3-4 times per day, where the radiators cool down and the boiler "fan" goes off, but pump still working, even though the boiler was only on for a few minutes and thermostat still calling for heat. Called British Gas out to look at it - each time they service it, but can't identify the fault. It will work for a few weeks after they visit, then start playing up again. Then if I call them out, it doesn't do the fault and works perfectly so they can't identify!!

Anyone got a solution as it is driving me mad!
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Postby Kenj » Tue Mar 29, 2011 2:31 pm

Hi nclair,

I am not sure that you have exactly the same problem as the silky951, as he said tht his pump continued to run, and you say that your fan is running when this problem occurs.

Worcester Bosch have a very good website that lists both an e-mail and a telephone technical advice line ( 3p per minute). They are probably more geared towards sales queries, but they may help you - you have very little to lose. They should know their boliers much better than BG and may be able to suggest a solution.

You could also write a letter of complaint to BG giving them say 6 weeks to remedy this intermittant problem or you will call in the manufacturer to repair the appliance, and then pass the bill onto them. This will focus their minds if nothing else.

Should Worcester Bosh also not be able to find any fault it would leave you out of pocket, so there is some risk in this straedgy.
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