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Plumberpro
Plumberpro, Home Appliance Technician
Category: Appliance
Satisfied Customers: 634
Experience:  Heating and hot water heating appliances experienced
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I have a worcester 24i rsf combi boiler that has just

Resolved Question:

hi i have a worcester 24i rsf combi boiler that has just started to give me problems. The main fuse (2A) in the boiler keeps blowing. If I replace the fuse the red light comes on and all appears fine. I can turn on the hot tap and the boiler ignites and delivers hot water. But when I turn the tap off the fuse blows. If I try and use the central heating control, I think the fuse blows as soon as demand is sensed. I have had one central heating engineer out to look at things and after 40 mins he said he couldn't find the issue. I'm just after some ideas to get this problem sorted. Could it be the pump? Or the PCB for instance? Any advice appreciated.

Is there a diverter valve in this system to control the flow of water between CH and hot water. And how can I identify it? Could this be stuck?

How can I check that the pump is working ok?

How can I check that the fan is working ok?

Submitted: 2 years ago.
Category: Appliance
Expert:  Plumberpro replied 2 years ago.
Hi , the things most likely to blow a fuse are the pump or fan , but I think in your case it is most likely the pump as the hot water goes through a separate section of the heat exchanger and the pump would run to cool the boiler when the taps are closed. .
The heating uses the pump straight away,so you need replace your pump .
Customer: replied 2 years ago.

Hi

Fantastic. Sounds very logical. I was wondering how the water flow through the pump related to hot water delivery and CH.

Would there be any way to confirm this other than by replacing the pump to see if the fault is rectified?

In theory the engineer who attended said the pump and fan were both okay.

Cheers

Dave

Expert:  Plumberpro replied 2 years ago.
Hi , was the engineer there when the fuse blew? The problem with intermittent faults is that they never seem to happen when the boiler guy turns up . You can check the pump and the fan ( both have motor coils that can short circuit when worn out) on ohms with an electrical multi tester . they should both be within a certain range .
Customer: replied 2 years ago.

I wasn't there when the engineer visited. But I believe he replaced the blown fuse a couple of times. So he should have seen it.

I've been replacing the fuse to see when it would blow. I believe the engineer said it looked like the hit water was ok but the CH wasn't. But when I got home and ran the tap there was no hot water.

So I replaced the fuse and got hit water. But noticed when the tap was stooped the unit would cut out with a blown fuse.

I have a multi meter so i can check the resistance. But no idea what the good range should be

Expert:  Plumberpro replied 2 years ago.
Hi for the pump , disconnect andmeasure across live and neutralneutral, should get between 170 and 270 ohms. 50 or less and 500 or more replace.
Most pumps will be around 200 .
For the fan
Between 40 and 80 ohms.
Less than 20 or over 150 replace
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Customer: replied 2 years ago.

Hi

Had BG engineer out today. He replaced the pump head and I now have CH and hot water.

Just wanted to let you know your answer was spot on!!

Expert:  Plumberpro replied 2 years ago.
That's great . all the best . please don't forget to rate me , thanks