CH still not working: 2 power flushes & new boiler

[ignoranceisntbliss]

Hello,

I'm at the end of my tether and would love some good advice . . .

To cut to the chase, I moved into my house 7 years ago and had central heating problems from the start. It ended with me calling in a guy who power flushed the system including cutting out a section of pipe and replacing it (because it had so much sludge). For about 2 years things were okay but then the boiler started cutting out from time-to-time when the central heating was on, only to return several hours later. I decided to change my Potterton boiler(conventional boiler, i.e. with water cylinder) and bought a Biasi condensing combi about 6 months ago which involved doing another power flush. All was well with the hot water until Autumn arrived and the central heating had to be switched on. In the last 3 months the boiler has cut out 3 times. Now, I have my doubts that the boiler is at fault but don't know where to start in remedying this situation. I've called out the installer and other plumbers but when they arrive and nothing's wrong, they can't (understandably) do anything.


Can anyone give me some sensible advice on this. I expect it's going to cost me more silly money to fix it but as I say, I've had enough.

Thanks . . . IIB.

 

[DP]

Do you have plastic Pipes?

How long did the power take? How was the system power flushed (should be one radiator at a time during which the panel is hammered with rubber mallet to dislodge sediment- this treatment continues till water flow is clear). Were chemicals used to remove stubborn pockets of sediment?

You could install a Megnaclean on the return pipe to catch muck as it makes its way to the boiler.

 

[ignoranceisntbliss]

Hi DP,

Thanks for the speedy reply. I guess you're suggesting that the flushes weren't done properly. I was there for the first power flush and think the guy did a thorough job going from rad to rad. I can't remember 'hammering' as such but do recall that the whole process took several hours. The guy who did the work was very experienced and I believe he did a thorough job flushing it all out.

Are there othe tests a central heating person could do to narrow down the cause of the problem apart from doing a powerflush?

The new boiler has some lights on the front and according to the Biasi manual the current problem is to do with the primary circuit - "Faulty primary circuit (no water or absence of flow)". I have checked the pressure gauge and it says that water pressure is normal at about 1bar.

 

[gas4you]

Could be if the system is still dirty, that a particle of dirt has blocked the pressure sensor that tells the pcb there is water in the boiler. This is usually a different sensor than the basic visual pressure gauge.