Vailant ecotec pro 28 pressure

[EvilDrPorkChop]

It's alright, all these s*** BG engineers are keeping me in business

 

[Johns23]

Hello. So a quick update…

Had the expansion vessel recharged and now seems ok. PRV ok. Pressure sensor replaced as faulty. Still loses pressure mostly when not in use. If I leave the house for any period it drops more. Have Dynarod coming out at some point next to see if they can detect a leak as British Gas are at a loss.

Thanks again for all the advice.

 

[ShaunCorbs]

Would want the prv changing as they can not seal once opened

 

[EvilDrPorkChop]

Wouldn't be unheard of for the HEX to leak back (Pin ***** inside) and back down the condensate drain, had a couple of Vaillants do this. Although it's quite rare.

 

[king of pipes]

Get em to take the burner out the heat exchanger it will be a mess in there if there's a leak internally in there .

 

[Johns23]

Ok thanks, I’ll suggest these if they don’t find anything with the Dynarod infrared thing as it sounds like they’ll be at a loss then.

 

[Mr F22]

Hi, the f75 is quite common for Vaillants. Pump/wps/low pressure/expansion vessel are a few of the things you will find.

I read above that the vessel was empty and was recharged ✔ and wps replaced.

My procedure as an engineer.
For low pressure. First to check all of the pipework, check the filter as they're prone to leaking.
Check all Radiator valves.
Pipework in cupboards, lofts, drain valves, inside the boiler etc.

Drain down the boiler. Recharge the expansion vessel, test the schrader valve with ldf.
While the boiler is drained, if you have a pressure reading say 0.3bar, then you will need to replace the wps (water pressure sensor £16) as you should have 0bar once drained. And showing you that the wps is given a false reading. Usually blocked showing signs of a dirty heating system. Check/clean filter.

Check outside at the prv (pressure relief valve) termination for any signs of a drip.

Also as previous engineers mentioned, check the heat exchanger for a split.

Another way to try locate the loss of pressure, once all system presure is topped up and running.
Turn off the flow and return isolation valves under neath the boiler (4mm Allen key, quarter turn). Leaving you without heating (turn off the heating at controls while isolated)
Leave isoated for "X" amount of days, then check your system pressure. If you have a lose of pressure while your heating is isolated, the fault is inside the boiler, have a visual of parts inside boiler then check the heat exchanger.

However if the hot water stayed on ok for "X" days, next step is to open the flow and return isolations.
If you get the pressure drop once opened, this tells you that the leak is on the heating circuit.

I hope this helps somewhat.

You're better off with a vaillant recommended Engineer in my opinion.

 

[Johns23]

Hi, the f75 is quite common for Vaillants. Pump/wps/low pressure/expansion vessel are a few of the things you will find.

I read above that the vessel was empty and was recharged ✔ and wps replaced.

My procedure as an engineer.
For low pressure. First to check all of the pipework, check the filter as they're prone to leaking.
Check all Radiator valves.
Pipework in cupboards, lofts, drain valves, inside the boiler etc.

Drain down the boiler. Recharge the expansion vessel, test the schrader valve with ldf.
While the boiler is drained, if you have a pressure reading say 0.3bar, then you will need to replace the wps (water pressure sensor £16) as you should have 0bar once drained. And showing you that the wps is given a false reading. Usually blocked showing signs of a dirty heating system. Check/clean filter.

Check outside at the prv (pressure relief valve) termination for any signs of a drip.

Also as previous engineers mentioned, check the heat exchanger for a split.

Another way to try locate the loss of pressure, once all system presure is topped up and running.
Turn off the flow and return isolation valves under neath the boiler (4mm Allen key, quarter turn). Leaving you without heating (turn off the heating at controls while isolated)
Leave isoated for "X" amount of days, then check your system pressure. If you have a lose of pressure while your heating is isolated, the fault is inside the boiler, have a visual of parts inside boiler then check the heat exchanger.

However if the hot water stayed on ok for "X" days, next step is to open the flow and return isolations.
If you get the pressure drop once opened, this tells you that the leak is on the heating circuit.

I hope this helps somewhat.

You're better off with a vaillant recommended Engineer in my opinion.

Thank you very much for the detailed response. Funnily enough the error code is now F.22 not F.75.

Dynarod due out on 4th Jan so going to wait until then to see if they can find a leak (hopefully not as topping up every third day). Then will suggest all the ideas thereafter : )

 

[Johns23]

One thing that does seem strange and at first I thought a coincidence but now not so sure…

When the BG engineer left, everything was fine for over a week. I touched the control to check the pressure and it was 1.3 like when he left. The next morning it was 0.7.

Everytime I press the controls to check the pressure, next time I look it’s gone down again. When I don’t check it seems to last much, much longer. It’s been ok for the last 24 hours so thought I’d test. Each time I checked in the last 5 hours it’s gone down .1 bar and just looked again and it now reads 0.8 from 1.3 before my experiment.

Surely that can’t be coincidence yet it makes no sense that simply pressing the radiator icon button twice to check the bar can possibly affect anything!

 

[cjg]

but are you doing it after the boiler has been running, water expands when hot then cools contracts, presure up presure down.