Vaillant ecoTEC plus 618 R1 System Boiler

[rheuuowa]

The boiler was installed in 2006 and after a period of 6 months satisfactory working now suffers continually from a failure to fire up with error code F.75 (insufficient water pressure)

A water pressure of 1.6 -1.7 bar on the boiler digital display is required to get it started. This corresponds to about 2.2 bar in the airing cupboard system filler point (cold main) and probably >> 3 bar in the ground floor radiators. As expected, when running the water pressure rises, but moves from the dark grey area into the red area on the boiler’s pressure gauge, and 2.6 -2.7 bar in the airing cupboard. This cannot be right ?

Periodically increasing the water pressure temporarily solves the problem, but a high pressure is still needed to start the boiler. The boiler is installed in the loft of a typical two floor detached house.

Except for one case, no water leaks/dampness has been observed anywhere in the system, or discharge from the system outlet. One VERY small leak (literally a few drips per day) in a downstairs radiator was identified. The system was depressurised to fix this and curiously the system functioned without a problem for a couple of months after this. The problem has now returned. Any ideas ? Thanks

 

[gas4you]

F75 is not insufficient water pressure, that is F22!

F75 is telling you that the pcb has not recognised the slight increase in pressure that is created when the pump kicks in. I hate to say this, but it is a known issue with the ecotec plus range. Usually cured by replacing the sensor (old ones orange) in the bottom left of the boiler. New versions are now black. Can also be caused by muck in the sensor due to poor flushing when the system was installed.

If still under 2 year warranty call Vaillant in to replace, or you could attempt it your self if out of warranty. No gas items have to be touched. Any good gas engineer who knows Vaillant will also be able to help you with this

 

[rheuuowa]

You are right of course with the exact definition of F.75. I have had an F.22 (dry fire) , but F.75 happens all the time.

The pressure sensor has an orange coloured base , so will follow up your suggestion and ask Vaillant to replace this (under 2 year warranty)

Hope to solve this domestic crisis ASAP ... cold water and cold radiators don't make a happy marriage !!!

Thanks for your informative and quick response.

 

[chrishutt]

A water pressure of 1.6 -1.7 bar on the boiler digital display is required to get it started. This corresponds to about 2.2 bar in the airing cupboard system filler point (cold main) and probably >> 3 bar in the ground floor radiators.

Is your boiler really 6 metres height above the airing cupboard? Do you live in a converted church?

 

[gas4you]

I wouldn't necessarily call F22 'dry fire' it is lack of system pressure. F22 will show at btewtween 0.3 and 0.5 bar on the digital manometer

 

[rheuuowa]

Vaillant describe F.22 as 'dry fire' in their Installation and Service book and give the following causes ...

Too little water in the appliance
Water pressure sensor defective
Cable to pump or water sensor defective
Pump blocked or defective
Pump output too low

On the one occasion I had this error the system pressure had dropped substantially, although I cannot recall the value on the digital display.

I checked my gauges again with the pump off (which it is most of the time !) and the digital display on boiler (loft) was 1.7 bar and the analogue dial in the airing cupboard was 2.2 bar. Basic physics tells me this difference is about a 5m head of water so guess one of the gauges is not telling the truth since the height difference is about 2.5m

Just to add ... the boiler makes several attempts to fire up and usually gives up after 4 pump runs. The pressure rises in the airing cupboard each time and ocassionly the will system will continue to run.

I am beginning to think that I have not done a wise thing in having the boiler in the loft because of all the pressure problems. Its ground floor predecessor operated faultlessly for 16 years with a small header tank !

Nice one about the church ... if I do not get this fixed I may have to take sanctuary in one ! Thanks for the helpful posts

Vaillant are coming on Tuesday

 

[gas4you]

TUESDAY why are they not coming out next day Is it because you wanted them then or they couldn't make it sooner. Next day service or I start shouting

 

[mayor]

YES its confirmed British Gas are useless !

It took them 5 visits in SIX days !!to finally say that they wold have to call in Valient in to fix the boiler.

Once the Valient engineer came, it was done in 45 mins !!!

The number one cause fo this error code is the PUMP ... folowed by the pressure sensor as covered by this topic already. The other interesting issue is that the Expnsion tank should ALSO be checke dto see if it has sufficient pressure.... if its too low then this will create a problem and if it is too HIGH as was the case AFTER the fact that the british gas engineer pumperd it up to 4 X the required pressure, then you will also have a problem ... dont ask me why as i am not technical ... i just listen.

Incidently i also had LEAKS from the BLACK rubber hoses... this was ALL related to the f.75 issue and the expansion tank being too full of pressure. THERE IS AN ALTERNATE FULL COPPER PIPE WHIH CAN REPLACE THE HOSE.... thankfully he service engineeer replaced mine.

Finally you will also need to check the filetr which is BEHIND the BLACK ( updated) pressure sensor. If this is DIRTY then this will affect the amount of water pressure hittying the sensor and hence it will mnot register... his will then cause he boiler to attempt to fire up and NOT IGNITE... the famous FOUR ATTEMPTS... for those of you who have witnessed this, will know exactly what i mean

try and ensure that you have a Mangnaflow fitted to your system as this will cut down on the debris getting into your boiler from a poor flushing of the system. By the way, as i havea SYSTEM boiler and NOT a COMBI boiler, the service guy TOOK THE FILTER OUT of the boiler as he said it was NOT needed. if you have a COMBI BOILER THEN CLEAN IT ( if you are corgi qualified)


He did say thyat this was the only range that had the f.75 fault code and in his opinion it was more headache then was necessary since there were MANY safty guards in place to prevent casuing harm to the boiler in teh abscence of the f.75 fault cide stopping the boiler from working.

SO check teh folowing.. in fact ALL of these should be checked...

1. PUMP
2. Pressure Sensor
3. Air pressure in Expansion Vessle
4. FILETR

good luck and i hope to God that Bl***y British gas read this..... thank god for Valliant Gas Engineers !

 

[gas4you]

I would hope that he has had it fixed within the last 6 months

I disagree about the pump though.

F75 is 90% the pressure sensor, but Vaillant are always trying to deny they have had a problem with them as per usual. It happens on the 600 & 800 series boilers.

Last I was told by the group service director, was that the pcb had 'been adjusted' so it was not so sensitive to the pressure increase it was looking for.

 

[mayor]

sorry forgot to mention that it was 5 visits in SIX days....

One of the first things they did was to change the pressure sensor... that did not do the trick because there were a million otherthings as described above that were collectivley causing the problem.

It would make sense that thet PCB needs to be readjusted..... is there a software upgrade or something similar for exisiting users ??

regards

 

[Deleted member 105431]

YES its confirmed British Gas are useless !

It took them 5 visits in SIX days !!to finally say that they wold have to call in Valient in to fix the boiler.

Once the Valient engineer came, it was done in 45 mins !!!

The number one cause fo this error code is the PUMP ... folowed by the pressure sensor as covered by this topic already. The other interesting issue is that the Expnsion tank should ALSO be checke dto see if it has sufficient pressure.... if its too low then this will create a problem and if it is too HIGH as was the case AFTER the fact that the british gas engineer pumperd it up to 4 X the required pressure, then you will also have a problem ... dont ask me why as i am not technical ... i just listen.

Incidently i also had LEAKS from the BLACK rubber hoses... this was ALL related to the f.75 issue and the expansion tank being too full of pressure. THERE IS AN ALTERNATE FULL COPPER PIPE WHIH CAN REPLACE THE HOSE.... thankfully he service engineeer replaced mine.

Finally you will also need to check the filetr which is BEHIND the BLACK ( updated) pressure sensor. If this is DIRTY then this will affect the amount of water pressure hittying the sensor and hence it will mnot register... his will then cause he boiler to attempt to fire up and NOT IGNITE... the famous FOUR ATTEMPTS... for those of you who have witnessed this, will know exactly what i mean

try and ensure that you have a Mangnaflow fitted to your system as this will cut down on the debris getting into your boiler from a poor flushing of the system. By the way, as i havea SYSTEM boiler and NOT a COMBI boiler, the service guy TOOK THE FILTER OUT of the boiler as he said it was NOT needed. if you have a COMBI BOILER THEN CLEAN IT ( if you are corgi qualified)


He did say thyat this was the only range that had the f.75 fault code and in his opinion it was more headache then was necessary since there were MANY safty guards in place to prevent casuing harm to the boiler in teh abscence of the f.75 fault cide stopping the boiler from working.

SO check teh folowing.. in fact ALL of these should be checked...

1. PUMP
2. Pressure Sensor
3. Air pressure in Expansion Vessle
4. FILETR

good luck and i hope to God that Bl***y British gas read this..... thank god for Valliant Gas Engineers !

Hopefully some of the shyte BG engineers on this forum will read this post. Nickso, Ollski etc?

 

[BGEngineer]

After stumbling across this post, I wonder how much of the information is credible. I cant believe the expansion vessel was pumped to four times its charge pressure, for one I dont think the diaphragm could take this and I can't imagine any engineer doing this. You have also said the Vaillant Engineer removed the filter stating you dont need it as you have a system boiler not a combi. The filter is obviously there to protect vulnerable components such as plate heatexchangers on a combi, but if its not needed on a system boiler then why did Vaillant put it in?

It sounds as though the BG engineer did everything right changing the sensor as this has been an issue in the past as gas4you mentioned. The Engineer also was right getting Vaillant in (which I'm sure we covered the cost) as of course, the manufacturers engineers are going to be experts on their own product range. Vaillant Engineers have to work on a range of about a dozen boilers we have to work on every manufacturers entire product range.

Our knowledge comes from experience working on different boilers. With new boilers we are required do a lot of reading of the manufacturers instructions to understand their operation. Failing this, phone calls to the makers tech help. With regard to Vaillant for the last few months the wait time on the phonelines has sometimes been hours which is not feasible when you have 10 breakdowns to visit a day. Obviously we needed the makers help on this occassion as it is an inbuilt fault on the boiler.

 

[mickyg]

expansion vessel was pumped to four times its charge pressure, for one I dont think the diaphragm could take this

you don't think so no? have a little think about it

 

[Agile]

After stumbling across this post, I wonder how much of the information is credible. I cant believe the expansion vessel was pumped to four times its charge pressure, for one I dont think the diaphragm could take this and I can't imagine any engineer doing this. You have also said the Vaillant Engineer removed the filter stating you dont need it as you have a system boiler not a combi. The filter is obviously there to protect vulnerable components such as plate heatexchangers on a combi, but if its not needed on a system boiler then why did Vaillant put it in?

Whilst its very laudable that you are willing to anomously post and try to defend your employer. I think that you may bot be aware of some of the worst aspects of some of your colleagues in the London area.

I recently went to a Puma which had been misdiagnosed by BG. The main fault was following a previous visit when Homeserve had been unable to diagnose a problem and the owners had called me to diagnose that the communication pipe to the EXV was blocked.

The nupties at Homeserve fitted an external EXV but did not appreciate the need to set the pressure to match the system and left it at the factory supplied pressure.

Later BG came and failed to measure or set it to the correct value or to clean or replace the the PRV and left the AAV closed and said they would replace the main HE after the owner had the system, power flushed.

I can , reset the EXV presure, cleaned the PRV, opened the AAV and chemically cleaned the microbore system.

The main HE was fine but I supose that BG still changed it as they had already misdiagnosed the problem.

Then there was the one with 44 visits over six weeks. I solved that without a visit by using phone advice to a TSM ( who was very relieved! ).

Tony

 

[BGEngineer]

I appreciate a lot of my colleagues dont always get it right, but there are a majority of us that do.

I have come across numerous Puma braided hose's becoming blocked and if I'm not able to clear it with a coathanger and there isn't clearance above, then boiler will come off the wall.

What makes a PRV or an auto air vent to let by.....a dirty system...so do you think we were wrong to quote for a powerflush?

Its just all to easy for people to bad mouth BG on here and its generally the same people. Just out of intrest what was the 44 visit job, its just by my calculations that would have meant we were there everyday (including saturday and sunday) for the whole six weeks! See how the truth likes to get stretched on here.

Mickyg-What are you getting at. Zilmet and Flamco both state max charge pressure of 1.0 for there 8l and 12l vessels.

http://www.bssuk.co.uk/bsscomm/assets/gfx/links/FlexconCommercial.pdf