Vokera Linea7 - fault code 04

[Antony2008]

Good morning all

My sister has a Vokera Linea 7 (pre 2006) which is intermittently cutting out showing fault code 04 - Low water pressure. Ensure pressure gauge is above 0.5 bar (see 3.1). Reset boiler.

The pressure gauge shows 1.5bar, this with the central heating cold.
I've reset the boiler using the mode selector switch, turning it to the OFF/ RESET position, then turning it back to the ‘hot water only’ or ‘heating & hot water’ position (after waiting the obligatory 2 minutes or so). After trying this a number of times & with fault code 04 re-appearing, I disconnected power to the boiler in the hope of resetting the fault. This doesn't work either.
The fault code returns regardless of the mode switch being in the ‘hot water only’ or ‘heating & hot water’ positions.

Any advice as to what is wrong and the steps I need to take to fix it will be greatly appreciated by my sister and her young family.

Many thanks in advance .

Antony

 

[nickso]

this model probably has the water pressure switch.

remove the two wires to it and link them together to prove the switch is faulty or the hole behind it is blocked. obviously do this when the power is off.

 

[Antony2008]

Thanks for your input nickso - I’ll check the pressure switch and its associated wiring.

Incidentally, after reading through the Installation & Service Manual, section '7.6.1 INSTALLATION FAULTS' shows possible causes for fault 04 as 'insufficient water pressure & Air in boiler’. Subsequently, I’ll bleed all the radiators to be sure this isn’t the cause of the problem.

One other – shouldn’t the AAV get rid of excess air in the system so should I be checking this component out too?

I hope to call on my sister tomorrow or the day after, so any further guidance from the forums illustrious gas engineers would be well appreciated.

Thanks.

Antony

 

[Agile]

Just stick to the advice that Nikso has given you and report back the result.

Trying too many things together just clouds the issue!

Tony

 

[Antony2008]

Appreciate your reply Agile. Only my sister's is a 66 mile round trip and I'd much rather go armed with all the info that I need to resolve any possible cause of the problem, rather than make individual trips!

Incidentally, she's had gas fitters call at her home to solve the problem - one who took a part away and told her the replacement wouldn't be available for three weeks (leaving her without heating/hot water for that time!!) and, after fitting the part, the problem still remains; another chap called recently who charged her a call out fee, got my sister to bleed a radiator, then said he'd have to dismantle the kitchen units to get to the top of the boiler??
Subsequently, I'd rather take the time out and help solve her problem without unnecessary wastes of time, money and aggravation.

Hopefully we'll solve it a.s.a.p.

Antony

 

[Agile]

I appreciate your difficulty and I am sorry she has had such a bad experience but thats quite common in our industry.

However, if several different so-called professionals have not been able to correctly diagnose the fault then surely you can see that you are not going to become a boiler expert overnight!

I know its easy to think that they are ignorant plumbers who left school at 15 and that anyone can do what they do better!

The reality is that a good grounding in engineering and electronics is needed to start with and then considerable experience in fault finding on boilers is required. That is not achievable overnight!

Tony

 

[Antony2008]

Thanks for your appreciation Agile.

As for any relative experience I may have, I’ve been an Electrical Commissioning Engineer for twelve years, supervising the electrical installation and then commissioning a variety of industrial plant (by and large controlled by PLC systems), both here and abroad. I have a BSc in Electrical/Electronic Engineering (with Microprocessor App’s), C&G Wiring Reg’s & Electrical Inspection, Test & Certification qualifications, so I guess I should qualify as a competent person, electrically at least! The downside is, as Agile quite rightly says I don’t have the experience of fixing domestic boilers – this is why I posted this topic in the hope that one of the gas engineers could put his/her finger on it immediately having had the exact or similar problem. He/she could then say “this/these are the possible cause/s, and here is/are the solution/s…”, hence saving me a little time and poor old sis’ & family’s cold extremities!

Ultimately, I just want to help my sister a.s.a.p.

Incidentally, I’ve resolved a small number of problems with my Vokera Excell 80SP over the years – replacing the internal by-pass shuttle & dhw diaphragm, AAV, time clock, slow fan speed resistor etc.
I know I’m letting myself in for some criticism here (as I’m not registered with any particular body) - just want to assure that I could be considered a 'competent person' - I’ve commissioned Maxon burners, both gas and oil, after having gone through (and passed) a training course at Maxon in Belgium. I’ve also commissioned tri-zone gas burners. Fortunately, working in those particular countries didn’t necessitate registration, so nothing illegal or unsafe took place, as will always be the case.
I know I have a long way to go boiler-wise, but I am learning! Just to be clear, I don't want to become a boiler expert - I'm quite happy doing what I'm doing thank you!!

Let’s not get side tracked please!!! – let’s fix the boiler!!!!

Antony

 

[Rob]

Haven't worked on a linea for ages...

...however iirc some were fitted with basic low water pressure switches. Others with active flowswitch and microswitch, which is more liklely in your case as the problem is intermittent.

 

[nickso]

iirc, all linea 7's have a wps, the linea 24/28's had half and half. ill check up on that later.

 

[Agile]

Anthony, you have the good grounding which is a first requirement and this is a very simple boiler.

Fixing a boiler is a progressive experience based on simple checks wirth the next being determined by the result of the last!

In this case we dont know which boiler your relative has so that has to be determined first and then the pressure or flow switched linked out in Nikso's BG test ( or voltage measured across it in my test ).

However, until that first test is done we dont know what to suggest next. Its 98% likely to reveal the problem!

I am surprised that with your background you cannot do all these simple tests yourself. I am also surprised that you seem to have one of these very basic and old models yourself! I should have expected a top of the range condensing boiler!

Having said that my Father had a PhD in electronics but I remember he once called someone out to repair his TV ! He did make a couple of valve TVs from kits when TV broadcasting started though. ( 12" round tubes! )

Tony