Vaillant ecoTEC plus 418 - Does NOT Work - HELP!!!!!

[Razor900]

I think the OP's gonna have too put the immersion on and wait for the ha to get their act in gear

I'm sure the installers would love to blame it on 'fiddling'

 

[sheilamurphy13]

Hi all, thanks for your comments. It definitely says F.73, just as it definitely said F.23 before as well as S.98. I put the emersion on for an hour this morning and have hot water for now. Also have an electric fan heater to take the chill out of the air. So much for these being economic with all this electric I'm using, good job it's not the middle of winter Would it make any difference if I restored it back to manufacturer settings

 

[gas4you]

S98 is reverse flow, the ntc's are checking why they are getting readings that are the wrong way round.

Can also generate S96 as I posted before.

I've come across this before, but with no fault codes.

 

[sheilamurphy13]

Thanks Dave, reverse flow/return NTC defective (tolerances too big) is what most codes have meant. So would it not make a difference to reset to manufacturer settings, definitely have to call back 'Engineer/Installer'

 

[gas4you]

Have a look at your pump. On the side there should be an arrow in the casting. This should (if it is a standard modern system) be pointing away from the boiler and connected to the inner pipe (nearest the flue) on the top of the boiler.

This inner pipe should be the one that is getting hot first if the boiler comes on.

 

[sheilamurphy13]

Where is the pump? Inside the Boiler or by my water tank in airing cupboard I know that sounds thick Found the arrow pointing away from boiler, but can't tell which one get's hot first cos still can't override error F.73

 

[Agile]

I dont think that you have yet done the specific test that we have all been badgering you to try as its an important diagnostic tool!

With the system cold, turn on and feel which pipe at the boiler gets warm first ( and tell us! ).

Tony

 

[sheilamurphy13]

It won't turn on, just displays F.73 No other symbols just lights up and F.73 All I've got is hot water using the emmersion and i guess that wouldn't heat the pipes down to the boiler would it

 

[davebgas]

Tony, she said it wont even fire now just this weird F73 fault.....

 

[gas4you]

As you cannot reset it, I could only guess that one of the ntc's has failed completely and the pcb will not let it reset as the resistances it is expecting are not being given.

Could be your problem all along and has now failed completely.

 

[Agile]

It won't turn on, just displays F.73 No other symbols just lights up and F.73 All I've got is hot water using the emmersion and i guess that wouldn't heat the pipes down to the boiler would it :

Well actually it could but would be confusing as it would heat up the return first!

Can you confirm that you have an open vented system with a small header tank in the loft or at a high point?

And that its not a sealed system with a red round expansion vessel and a pressure gauge showing about 1.5 Bar on the black pointer?

Tony

 

[sheilamurphy13]

It is an open vent, I have hot water tank upstairs, not sure if there is a small header tank in loft but pipes head up to there. There is no pressure gauge etc it is not a sealed system.

Can someone please tell me what NTC is

 

[davebgas]

Having a stab in the dark and the info we have, I think the Thermistor is bust. PCB is confused with the readings as already mentioned and is just sitting waiting...

 

[gas4you]

As you cannot reset it, I could only guess that one of the ntc's has failed completely and the pcb will not let it reset as the resistances it is expecting are not being given.

Could be your problem all along and has now failed completely.

Having more problems with your hangover?

 

[Agile]

Sheila, I am refering to the heating system ( not the hot water! )

Can you look in the loft and look for a header tank?

Just to make sure there are not the sealed components been put there when you were not looking?

And if you find the header tank that there is at least about 100 mm of water in it?




To the engineers:-

The F73 is a low water pressure fault indication! Nothing to do with NTCs!

But the boiler if properly configured as a 418 then it should not be showing that in any case.

If its properly configured as a 418 then I would be expecting a faulty PCB.

Unfortunately the low skills of most who do HA contracts mean I have no confidence they have checked and commissioned the boiler properly or at all!

Tony