Vaillant ecotec plus problem

Timmo · 3 Jul 2007

hi all need some help with a vaillant eco tec plus 618

It is plumbed into a sealed system with three zones, 1 x hw and 2 x CH.
On start up it has always been temperamental in that; if it starts on HW only chances are it will run ok and the HW system works as you would expect. there is an auto air vent on the flow to the cylinder

If it starts on any other zone, it will fail to start up quoting fault f75 (this means (no pressure rise was detected on turning on the pump) the cause in the manual states (water pressure sensor and or pump defective. too little water in appliance: connect external expansion vessel to return) I don't believe there is a need for an further expansion vessel as the pressure rise when hot is minimal.

I believe the pump works fine because when the appliance does start up I can call for heating at the same time and it all works fine. it is unlikely the pump fails intermittently. i.e. not creating the pressure rise

it could be a dodgy water sensor but until now (i had to drain it down in a hurry) it works ok on HW, at least most of the time.

I am minded that this is a water flow issue, iether through an air lock or something. it is a new system so unlikely to be a blockage but the heat load is approaching maximum

So, can anyone shed any light on this, is it a common fault or am i missing something,

Agile · 3 Jul 2007

The larger the heating load the greater the flow!

I cannot guess the problem but its often not what the code implies.

Tony

simond · 4 Jul 2007

It's unlikely to the the water sensor because your are lowering the system resistance the more circuits you open, and you have determined that it always works with HW.

I suspect a wiring problem with the CH zone valves but have you made sure the internal auto bypass is not fully wound shut? Is the flow and return the right way round?

gas4you · 4 Jul 2007

F75 is a well known fault with the ecotec plus range, especially if the sensor is the old orange capped one, bottom left inside case. The other cause for this is muck in the system due to insufficient flushing during installation.

If its under warranty call Vaillant in to replace sensor. I doubt very much it is a problem with anything else.

Timmo · 4 Jul 2007

gas4you

I love you ( in a very non sexual macho sort of way)

I knew it!!! When i get the damn thing started it all works perfecty. I have to trick boiler into believing there is water flow by partially draining or filling on start up. I Was very careful when I installed it to ensure that it was flushed properly 2 x cold and one hot flush so i know its not sludge or gunk.

The sensor is indeed the one that you describe although it isn't under warranty.

I tried to find a parts supplier on the net and failed, lots to choose from but none that would identify the sensor. Can you advise on where I can get this part.

gas4you · 4 Jul 2007

It must be only just out of warranty, I've been fitting them since they were launched and can only think of one or two that has had their second service yet

I take it you know it is a 2 year warranty

gas4you · 4 Jul 2007

You could try taking out ch sensor and cleaning.

Parts center do them VAIL 253595 SENSOR parts center no 476248 £22 + VAT retail

Timmo · 4 Jul 2007

Gas4you

I didn't know it was a 2 year warranty, although i am not sure where I stand as it was a DIY job installed by my good self.

I need to drain the system down at the weekend and fit a rad. I intended to check the sensor and the pump so your advice is again very good. Is the sensor in a dry pocket do you know? like some other combis.

I do recall though upon its very first start up i had the same problem so I don't hold out much hope, but for the sake of 20 minutes or so..........

I will try vaillant parts and see what they say before I spend my £22

Once again your advice is greatly welcomed

Timmo · 4 Jul 2007

just found this on the Vailllant web site

Information for installers/service engineersProduct Quick Search
Energy type ... High efficiency boilers High efficiency soluti.. Standard efficiency bo.. Cylinders Controls & diagnostics Solar Commercial boiler range Air conditioning range Groups ...

Find a local installer ...We are in the process of carrying out a free of charge modification to all the relevant ecoTEC boilers for which we possess installation addresses. We are seeking your help to identify further boiler installations.

Please call our free helpline 0800 0778055 (Monday - Friday 8am - 6pm, Saturday 9am - 4pm and Sunday 9am - 12pm) with the installation address details of any ecoTEC plus or ecoTEC pro boilers that you have installed or serviced. We will then contact the user and arrange for an engineer to carry out a simple modification to the boiler free of charge.

Alternatively, contact us at [email protected] if you would prefer to send in the relevant ecoTEC plus or ecoTEC pro installation address details in this manner.

We apologise for any inconvenience this may cause and thank you in advance for your cooperation.

Ashwood Heating · 4 Jul 2007

Timmo said:
just found this on the Vailllant web site

Information for installers/service engineersProduct Quick Search
Energy type ... High efficiency boilers High efficiency soluti.. Standard efficiency bo.. Cylinders Controls & diagnostics Solar Commercial boiler range Air conditioning range Groups ...

Find a local installer ...We are in the process of carrying out a free of charge modification to all the relevant ecoTEC boilers for which we possess installation addresses. We are seeking your help to identify further boiler installations.

Please call our free helpline 0800 0778055 (Monday - Friday 8am - 6pm, Saturday 9am - 4pm and Sunday 9am - 12pm) with the installation address details of any ecoTEC plus or ecoTEC pro boilers that you have installed or serviced. We will then contact the user and arrange for an engineer to carry out a simple modification to the boiler free of charge.

Alternatively, contact us at [email protected] if you would prefer to send in the relevant ecoTEC plus or ecoTEC pro installation address details in this manner.

We apologise for any inconvenience this may cause and thank you in advance for your cooperation.

Been about a while that one. Problem with burner seals

gas4you · 4 Jul 2007

Try calling the 0870 number given with installation instructions and placing a warranty call, they can only say no

Isolate and drain down boiler

if it was dry pocket then crud and pressure couldn't affect it

As Ashwood says, recall only affects burner seal and yours should have had it replaced with the new graphite one at the 12 month service

But I suppose you didn't have that done either

Timmo · 4 Jul 2007

As for the dry pocket thing

DOH

and....er Ill get the seals.

Coblers shoes and all that

yaniss corgi · 10 Oct 2007

i don't know if you sorted problem, but take pump out and look for scale deposits blocking pump fins/also take out sensor /filter behind ,you remove the hose and pull the filter out from behind the sensor
i fitted 2 vaillant eco tec plus 637 side by side 8 towel rails 2 premiere 210 ind cylinder ,5 8 way under floor manifolds and 6 rads on third floor plus extra expansion vessel,
used cheap flushing chemicals had been ok on non condensing boilers
spent 1day 4 hrs cleaning system very important job, fine for 1 month
then f75 since spent 4 days power flushing probably cut out f7540 times before changing sensors fitted 2 magnetite filters that was 3 months ago phone call tonight f75 again ********! would you believe within 3 months a 28 mm pipe could block solid with scale that was the first i knew of the real problem. **********! i have also fitted 6 other vaillants all of these are brand new complete systems in 30 years in this business, i've never took a pump out for blockage maybe a lump of solder i was told by a rep from a certain company from germany that these boilers don't like cleansing . i have always make sure i can drink the water before adding inhibitors. i
have also fitted 7 other boilers from sanduval lots of vaillant parts in them as well one so far has scale and one of the other vaillants mentioned also has scale i dont know how much power flushing i'm going to have to do
condensing boilers i hate them and i've always said there the best i've fitted at least 500 pre condensing if any body can throw any light

gas4you · 10 Oct 2007

F75 is a common known fault with the ecotec Plus, especially if it has the orange pressure sensor fitted. New ones have the black one.

I personally have had only 2 giving F75 and that was after about 9 months use.

My mate the Vaillant engineer just changed the pressure senosr and no problems since.

F75 is when the pcb does not detect a 0.1-0.2 Bar pressure increase when the pump spins.

gregatyou1 · 21 Jul 2010

my boiler has also a f75 fault and leak water 1 month outside warranty

i have been quoted £295 for a call out but if this is a know fault should the not come out free of charge

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Vaillant ecotec plus problem

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