I have a Worcester Greenstar 30i that’s 9-10 years old, about 3 years ago the heat exchange plate all of a sudden started getting blocked with what’s in the picture attached. I’ve had it cleaned out, exchanger plate replaced twice, every radiator in the house has been replaced, inhibitor put in the system, electrolytic inhibitor installed and nothing has stopped it. 2 months after having all my radiators replaced it’s blocked again and I’m losing the will to live, nobody seems to know what’s causing it. Is it limescale, is it corroded copper, is it the plastic pipe, is it a deeper problem with the boiler? I live in a hard water area but why was it ok for so many years before? My British Gas friend who has to clean the plate out and keep changing it doesn’t know either, said he’s never seen anything like it before. Please please help!!!
Blocked heat exchange plate
- Thread starter Mitch2610
- Start date
How often were you needing to top up the water pressure?
- Joined
- 5 Nov 2024
- Messages
- 4,009
- Reaction score
- 2,033
- Country
Looks like limestone chippings rather than limescale. What’s the temperatures set to?
Pressure seems to be fine, I was having to regularly but pressure vessel needed changing and then didn’t need topping up anymore but problem with plate still carried on
Hot water is only on 48 degrees, central heating is on 82 degrees
- Joined
- 5 Nov 2024
- Messages
- 4,009
- Reaction score
- 2,033
- Country
This could be the problem then, afaik scale starts to come out at about 60 degrees
- Joined
- 5 Nov 2024
- Messages
- 4,009
- Reaction score
- 2,033
- Country
Not really. Try reducing it see how you go and then gradually increase it if you needed to
Not that I'm aware of
My thought - Constant topping up, means fresh input of hard water, and a fresh amount of limescale to build up. That would become loosened, and block up the plate.
You say the rads are getting bunged up which means the primary water side, you mention the exchanger plate, do you mean the main boiler heat exchanger or is it a combi boiler which will have a PHEX (Plate heat exchanger).? If it is a combi then the DHW side of the PHEX should/might show signs of blockage as well, did you look at this side?.
It was happening way before the pressure vessel needed changing so wasn’t having extra water put into it for the first 2 years it was happening, the vessel only went quite recently
It’s a combi so plate heat exchanger, it’s in both sides of it as well, I thought changing all my rads that needed doing anyway, a new plate heat exchanger and a fresh dose of inhibitor would work but sadly not
It might be worth getting the mains water and the scale analysed/tested since this is the common denominator, even though the primary side was not being topped up and you were getting the same problem, the system was probably refilled from the mains.
If not done so, Install a combined mag & particulate filter on the boiler inlet, it might catch some of that stuff., even if only a temporary measure.
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
