we have the above boiler ...when running a bath we noticed that after 3-4mins the water would run cold ..got a guy in and he replaced the pcb board for us , problem was fixed...then about 5 weeks later it started doing the same problem again, water would run cold ..we then noticed that the fault light was flashing slowly on the boiler , we called up the same guy and he came back to look at it , hummed and harred and said it could be the internal thermostat , boiler keeps thinking its overheating and causes the fault ...well as im still waiting for him to come back and repair it ...i though i might as well ask if anyone know what the problem could be , does it sound like the internal thermostat...any help please ?

simon, May 2008

The red warning light is flashing

Just moved into the property where the boiler has been off for a while. It has just been serviced but the red light is flashing and i have no hot water or heating.

Can anyone help pls ????

Craig williamson, January 2014

did you fix it as I have just posted same question about mine.

Hi, I wonder if anybody could help me please, My Worcester 28 SI II will cut out after filling half a bath, then the red light flashes, after resetting it just trips again straight away and again and again.
Same happens with central heating, it will run for 20 mins then cut out and wont reset.

However here is the weird bit, if I then leave it for 40 mins or so to cool down it will again fill half a bath or will heat house for 20 mins.
Its 9 years old and had a new pcb 6 years ago, this does sound to me like a dry joint again on the pcb or even a diode or capacitor that expands when the pcb gets hot. But im not the expert you are. I don’t want to replace the pcb and find out its just the same. Any ideas please??
Thanks all in advance.

meurig, July 2012

The above boiler works on the domestic water okay but when workin the Central Heating decides to cut out after a while and the warning light flashes about 4 times a second. Anyone got an idea which part might be faulty. One engineer thought it might be Thermister on the Central Heating side but another said he didn't think so???

Paul Jenkinson, February 2012

i know what the problem is but dont know how to fix it ....the gas valve isn't modulating down when the water is hot therefor staying on full burner, the boiler thermostat will then kick in and cut off the boiler till it cools down, which explains the hot and cold changes...
i fitted 2 new pcbs,1 gas valve a transformer and a new hot water stat , still the gas valve dosn't modulate; well got to say not one of wocesters best

keith, April 2010

Hi Simon speak to the guys at Worcester.You will find the contact details on the site worcester bosch. Ask for technical & give them the details.I have used them a few times & they are very helpful. They will guide you through the stages & will help yOu far more than you previous plumber/plumbers

Chris, September 2008

The fan runs for 2 seconds on the boiler but the burner fails to light, Red light flashes every 4 seconds. PCB Board has been changed prior to visit. Any Ideas.
Thanks Russ

RUSS, July 2008

I have the same problem. Did you manage to get it sorted? Any advice/help would be appreciated.

John

goblin247@googlemail.com

John, July 2008

i imagine the boiler turns itself off,for example no flame and thats why your getting cold water,well if this is the case then yes themostat has gone down as this a safety feature on all boilers

scott-sharon@blueyonder.co.uk, May 2008