Worcester 28i Junior Problems

[rossfstan]

Hi folks, I have been a long time lurker and love the information available you guys put forward, I will appoligise in advance for my first post being a question. SORRY

Ok, I am having issues with my 5 year old boiler, Worcester Bosch 28i Junior.

Until recently the boiler has been working fine no issues whatsoever since being installed. A Couple of weeks back the red warning light was flashing and the unit was in lockout, I reset and again the red lights flashed (4 times a sec). I had a look through the manual and this could be a number of problems.

I took off the outer casing and the inner casing, upon inspection i could see the Air pressure switch was melted quite badly and thus it was not registering the fan running correctly.

I ordered a new air pressure switch and replaced the melted one. I ran the system and everything seemed to be working correctly. The system ran for about an hour and again it locked out with the red light flashing 4 times a second. I noted at this time the outer casing of the unit was quit hot to the touch. I tried to reset by pressing and holding the reset button but again it went straight to lockout.

I switched the unit off at the mains and left it to cool before opening it up, when I returned i switched it on to test prior to opening and it worked (making me think some sort of overheating is occurring)

Today the system was locked out again, i opened the inner chamber and saw the air pressure switch was melted again.

I swear i am at a loss with the unit and am considering just biting the bullet and replacing it.

any help would be greatly appreciated

 

[ianmcd]

You shouldnt be doing this work yourself as you need to be RGI to work inside the combustion chamber switch it off immediately and get an RGI it is a very common problem with that boiler the PCB has gone and the fan stops but the burner remains on, please isolate immediately it is very dangerous

 

[rossfstan]

thankyou for your prompt reply ianmcd, excuse my ignorance, i assumed the combustion chamber was the section where the gas was ignited. I will not open the inner section again and inform a RGI of what you have told me?

How confident are you in it being the PCB, I would love to have any relevant parts required prior to the RGI arriving.

How would one test a PCB to tell it was faulty?

 

[ianmcd]

Almost certainly the PCB the fan stops but the burner remains lit, as the fan is not running the flames lick up outside of the combustion chamber and melt the APS have had loads like that

 

[Gasguru]

It's a common problem due to another Worcester design fault. The fan fails to run at high speed when the burner ramps up. Normally the pcb, tee piece and APS require replacment.

 

[rossfstan]

I read that worcester do a fixed price repair for £200, you wouldnt know the number or link for thi, if i need a board i might aswell have them fit i and have 12 month gurantee.

 

[ianmcd]

Not sure its £200, last time I used that it was £270 might be different for different boilers but even at £270 I would recommend you go for it their contact centre number is 0844 892 3000