So what do you suggest ?.
High pressure cleaning will remove everything anyway and the strip the concrete of the wall also if you wish and leave the concrete open to attack by mildew and spore growth.
I find I have to clean my concrete and walls yearly with a high pressure...
I was doing some head scratching and just figured that out as you posted. It must be late.
Well done any way.
I think you will get some grief however about the open vent.
Go to the heat bank website and click on "Mains conversion...
I can see the flow switch on one side but the outlet on the other side of the plate seems to T back into the pipe connected to the cylinder between what looks like a chrome isolating valve (or could be a non -return valve) and a galvanised pipe in the corner.
Can this be right ...
Like this Paul.
Problem is the thermostatic sensor senses cold water initally, so the flow passes through the second combi until the sensor senses heat and shuts off the flow through the second combi .
Paul Barker wrote
A blend valve has three ports. Cold inlet - Hot inlet and Blended outlet.
Do you mean a thermostaticaly controlled three port divertor.
It sounds good if I knew what you were talking about, a diagram would be good.
Think of your prv as a spring loaded tap. (purely hypothetical)
But it never opens as the pressure is too low.
Then some day someone turns the pressure up or manually turns it open.
Hey presto, the spring loaded tap opens and discharges filthy water.
Because the spring...