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I would like to change the PCB board 8 748 300 484 0 in my Worcester 28i Junior.
Boiler G.C. label see below picture (G.C. 47 311 70 NG, 47 311 72 LPG).
Reason - voltage from PCB to the flow sensor (when disconnected) is 10.3V instead 5V. According to the Boiler manual I have a PCB 8 748 300 484 0. DHW and CH works fine. Even with Alexa/Hive which I done two years ago
A bit noisy fan and bearing need to be replaced, but that is another simple job for later on. Some of upstairs radiator pipes get hot when CH is OFF and hot water tap is ON. So maybe something is wrong with PCB or flow sensor (my boiler doesn't have diverter valve as I thought when I start digging what might be wrong), so I've decided to buy some PCB and try it.
Found used on eBay for £27.
When I received it, I got below PCB with No. 8 748 300 555 0. The only difference between them is the white part on the left.
My PCB has this part with a bit different shape and blue colour as you can see above circled in red. The two connector plugs are the same.
PCB description on eBay was with both numbers: 8 748 300 484 0 / 8 748 300 555 0. When I asked the seller if 8 748 300 555 0 would fit my boiler, he agreed and said it is compatible with my Worcester boiler as this PCB board has two numbers and I can use either.
But I still wonder if this 8 748 300 555 0 will be fully working and what actually is the difference between them? Maybe only latest version/some upgrade..... I know there are similar PCBs with the same board but for Worcester boiler Si and the PCB part number is different 8 748 300 488 0.
I do not want to open the bag, replace it and find out it is not good for my Boiler.
What do you think, what problem did you have with your PCB and which one did you replace?
Please help me if you can
Boiler G.C. label see below picture (G.C. 47 311 70 NG, 47 311 72 LPG).
Reason - voltage from PCB to the flow sensor (when disconnected) is 10.3V instead 5V. According to the Boiler manual I have a PCB 8 748 300 484 0. DHW and CH works fine. Even with Alexa/Hive which I done two years ago
A bit noisy fan and bearing need to be replaced, but that is another simple job for later on. Some of upstairs radiator pipes get hot when CH is OFF and hot water tap is ON. So maybe something is wrong with PCB or flow sensor (my boiler doesn't have diverter valve as I thought when I start digging what might be wrong), so I've decided to buy some PCB and try it.Found used on eBay for £27.
When I received it, I got below PCB with No. 8 748 300 555 0. The only difference between them is the white part on the left.
My PCB has this part with a bit different shape and blue colour as you can see above circled in red. The two connector plugs are the same.
PCB description on eBay was with both numbers: 8 748 300 484 0 / 8 748 300 555 0. When I asked the seller if 8 748 300 555 0 would fit my boiler, he agreed and said it is compatible with my Worcester boiler as this PCB board has two numbers and I can use either.
But I still wonder if this 8 748 300 555 0 will be fully working and what actually is the difference between them? Maybe only latest version/some upgrade..... I know there are similar PCBs with the same board but for Worcester boiler Si and the PCB part number is different 8 748 300 488 0.
I do not want to open the bag, replace it and find out it is not good for my Boiler.
What do you think, what problem did you have with your PCB and which one did you replace?
Please help me if you can
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