New unvented system - ground floor losing pressure

[Scott_D]

Post some pictures of the boiler, cylinder, expansion vessels, manifolds etc.
Might give us some clues

 

[plastics77]

Hopefully these pictures help?

 

[EvilDrPorkChop]

Tbf it doesn't look a bad job overall, and they've put additional expansion in which is good.

Regarding the leak, it's probably highlighted the fact when the system has gone sealed. It was more than likely leaking before, but the system refilling itself. The fact you've got pressurised has probably made it leak worse, however on the old system it would have only of got worse anyway than better.

Unfortunately you'll have to try and locate the leak.

 

[PETE 123]

have you tried a flir camera looking at floor when heating is on to see if a leak shows.

 

[plastics77]

Thanks- what's a flir camera? Thermal imaging? Not yet, I thought that would be next step via insurers track and trace...

Interestingly, filled it back up tonight to 1.5bar from 0, to get some heating for the young kids overnight. Now the heating wont come on, it is showing a F75 error code now. Before it was only showing F22, which would go once refilled.

Sounds like I will have to get in touch with insurers to help find the leak, but hope it isnt actually an issue with the boiler as I will be charged and referred back to the boiler contractor!

 

[plastics77]

Ok quick one- please.
They came back to bleed radiators and then seemed to bleed something on the unvented cylinder.
Now, the analogue pressure guage on the expansion vessel is measuring 0.4bar less than the pressure on the digital reading in the boiler.
E.g. this am boiler saying 1.4 bar, analogue dial off the expansion vessel saying 1.0bar!!

The plumbers say this is normal, it is measuring 2 different systems. That doesnt make sense to me, they have always previously been reading the same. Is this normal??

 

[Ben-gee]

The digital boiler one is measuring the pressure in the central heating circuit.

The manual dial one is measuring the pressure in the hot water system.

As your plumber says, these are separate.

 

[plastics77]

Thank you
So you could get pressure loss to below 1 bar in the hot water system, but still be ok at 1.4bar for central heating. If it is the downstairs hot water system that is losing pressure, does that mean the leak is in areas supplying hot water taps, e.g. toilet sink or kitchen, rather than radiators?
When I use the filling loops to re-pressurise the system it is the manual dial one, below the expansion vessel , that I am checking is increasing back from 0 to 1.5bar, but does that mean I could be overpressurising the central heating system above 1.5bar, if it is higher in that system??

 

[EvilDrPorkChop]

The manual gauge will be the correct pressure for the central heating (It’s nothing to do with the Hot Water) the digital gauges on the Vaillant’s always over read and never give a true reading. When the pump kicks in you’ll notice there’s positive pressure on the sensor and it goes up too.

 

[Ben-gee]

The evilDr is correct! The dial pressure gauge is on the grey expansion vessel for the heating system.
The hot water system has the white expansion vessel, no visible dial, my mistake.
So yes, both pressure reading devices are for central heating system.