New unvented system - ground floor losing pressure

[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.

 

[plastics77]

Ok thanks both, that makes more sense. They were always reading the same value until the last week or so where the digital vaillant reading started reading about 0.4bar higher than the analogue one. Pressure dropped again and I refilled to 1.5 bar a day or two ago. All fine. Today, had dropped again overnight, but this time after re-pressurising using the filling loops, the pressure went back up but the F75 code has arrived again so nothing working, no hot water no heating, very frustrating! I know the installer will say to just reset the boiler but not comfortable doing that - surely just because there might be a pipe leak , doesn't mean there is nothing wrong with the boiler - the F75 code has only started coming recently, could the pressure sensor have blown?

Will call insurers on monday to find the leak but worried that they will say there is a problem with the boiler that hasnt been sorted out yet..and until then we got young kids and no hot water or heating for a couple of days, nightmare!

 

[EvilDrPorkChop]

Ok thanks both, that makes more sense. They were always reading the same value until the last week or so where the digital vaillant reading started reading about 0.4bar higher than the analogue one. Pressure dropped again and I refilled to 1.5 bar a day or two ago. All fine. Today, had dropped again overnight, but this time after re-pressurising using the filling loops, the pressure went back up but the F75 code has arrived again so nothing working, no hot water no heating, very frustrating! I know the installer will say to just reset the boiler but not comfortable doing that - surely just because there might be a pipe leak , doesn't mean there is nothing wrong with the boiler - the F75 code has only started coming recently, could the pressure sensor have blown?

Will call insurers on monday to find the leak but worried that they will say there is a problem with the boiler that hasnt been sorted out yet..and until then we got young kids and no hot water or heating for a couple of days, nightmare!

Just reset, the worse than can happen is that it'll just do F.75 again.

More than likely theres dirt in the pressure sensor. They are very sensitive, and tbh a bit of a nightmare. You could try adding a tiny bit more pressure in, then reseting. That usually sorts it.

 

[plastics77]

Ok thanks, did it, worked.
Will just have to keep re-setting until they find the leak!

 

[Scott_D]

You can always turn on the immersion heater for hot water?
F75 is usually a boiler issue
Is it possible to leave the leaking zone isolated until it’s fixed?
I’m not sure if that boiler requires an auto bypass but I can’t see one in the pictures

 

[plastics77]

You can always turn on the immersion heater for hot water?
F75 is usually a boiler issue
Is it possible to leave the leaking zone isolated until it’s fixed?
I’m not sure if that boiler requires an auto bypass but I can’t see one in the pictures

Yup plumber not coming and insists not a boiler issue, says it's a leak that needs sorting. He said just keep filling up and resetting boiler until leak sorted. Good point re. Electric immersion heater, I'm not sure where that switch is on this new system, will have to ask.

They did isolate upstairs and no pressure loss, so they think leak is downstairs but no sign of water damage so no idea where. If we isolate off again, means no heating at all downstairs and things are going to get cold over next week or two.

What's an auto bypass??

 

[Vee]

Yup plumber not coming and insists not a boiler issue, says it's a leak that needs sorting. He said just keep filling up and resetting boiler until leak sorted. Good point re. Electric immersion heater, I'm not sure where that switch is on this new system, will have to ask.

They did isolate upstairs and no pressure loss, so they think leak is downstairs but no sign of water damage so no idea where. If we isolate off again, means no heating at all downstairs and things are going to get cold over next week or two.

What's an auto bypass??

Which model Ecofit Pure (Since its not an Ecotec) do you have? Does the model number start with 4 or 6. There is a badge on the underside?

 

[plastics77]

Which model Ecofit Pure (Since its not an Ecotec) do you have? Does the model number start with 4 or 6. There is a badge on the underside?

Hi there, it's an Ecofit pure 630

 

[Scott_D]

Yup plumber not coming and insists not a boiler issue, says it's a leak that needs sorting. He said just keep filling up and resetting boiler until leak sorted. Good point re. Electric immersion heater, I'm not sure where that switch is on this new system, will have to ask.


What's an auto bypass??

follow the cable to hopefully find a switch for the immersion

An auto bypass will open to give water somewhere to go if the pump is running but zone valves are shut.
Nothing to do with your leak problem

 

[EvilDrPorkChop]

All Vaillant System boilers have an auto bypass integrated so doesn't need an external one.