Vailant ecotec pro 28 pressure

[Johns23]

Hello.

I’ve lived in the property for 4 years and anytime the pressure got low (0.8 bar) I would use the fill taps to release more water into the system. Ever since British Gas did their annual boiler check about 3 months ago, I’ve had to do this too up method more and more. My pressure is now 1.8 bar which is too high but seems to lose pressure and need topping up every other day. I can’t see any leaks and the pressure reading isn’t changing so any ideas why I’m losing my hot water and heating until I let some more water into the system and then it fires straight back up?

 

[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.

 

[Mr F22]

F22 / low system pressure.
Do you have a boiler manual? As fault codes will be located in the back of the book.

Pushing the button to check the system pressure should not effect that.

As a rule, I allow 0.4 bar rise on the gauge when the heating is on ( the pump on) give or take 0.1 bar.
As cjg said water expands when heated.

For example let's say at rest the boiler reads 1.2 bar and when the heating is on, it goes upto 1.6 bar or 1.7 bar.
Anything higher that 0.7 bar rise ( say 1.2bar to 2bar) will most likely mean your expansion vessel hasn't got the correct charge.

It may well be that you have a slight leak somewhere on the system, causing the low pressure over X amount days.
Or that it just requires topping up the system pressure via the filling loop, to 1.2 bar at rest. Not left on 0.8bar.

 

[Johns23]

Hello

Thanks for the replies. Yes I had taken into account the pressure changes when heating is on but the base pressure level keeps dropping. I’ve had to fill it again today as went down to 0.6 so now back at 1.2 and will be 0.6 in a few days again (sooner if I check on it ).

The expansion vessel was recharged as was flat and they checked it again last time and was fine. Dynarod of the 4th Jan so hopefully some answers then if it is a leak. Meanwhile I’m topping it up so more leaking if there is one for another few weeks

 

[Johns23]

Hello again.

Another thing I’ve noticed … I have the wireless thermostat set at 20 degrees and the whole house was boiling hot. I checked the thermostat which is next to the boiler and it said 20 degrees (it felt way higher) and the upstairs bedroom was 23 degrees and that’s usually colder. The boiler was on and all radiators were pumping and had been for ages and the control panel on the boiler was flashing an egg timer which it keeps doing. I know this is to prevent it from cycling on and off but again I’ve never noticed it before and it seems to be like the boiler should be switching off but isn’t as wrongly believes it’s still at just 20 degrees. If that makes sense?

 

[Mr F22]

Position your wireless room thermostat closer to a radiator/heat source for a more accurate reading. Keeping away from windows and external doorways.
Try turning your thermostat down to 19.

Say the place you leave the room thermostat is in cold area, the heating will stay on longer trying to reach the 20° on the wireless stat. If you position too close to a Radiator it will reach temperature and turn off the heating quicker.

Or try putting the wireless stat in the hot bedroom and see how you get on

Egg timer, engineer to check the filter is clean. Allowing circulation.

I would go for a gas engineer and not dynorod.

Check visually: Filter for a leak, Radiator valves, Visible pipework, External PRV, drain offs etc

 

[Johns23]

Position your wireless room thermostat closer to a radiator/heat source for a more accurate reading. Keeping away from windows and external doorways.
Try turning your thermostat down to 19.

Say the place you leave the room thermostat is in cold area, the heating will stay on longer trying to reach the 20° on the wireless stat. If you position too close to a Radiator it will reach temperature and turn off the heating quicker.

Or try putting the wireless stat in the hot bedroom and see how you get on

Egg timer, engineer to check the filter is clean. Allowing circulation.

I would go for a gas engineer and not dynorod.

Check visually: Filter for a leak, Radiator valves, Visible pipework, External PRV, drain offs etc

Thank you very much for the reply. I will try all of those things as having to top up almost daily now. Have a great Christmas!