Vaillant Sine 18 Fault. No Central Heating.

[AllyBongo]

NTC relates to the thermistor, like PTC. Negative or positive temp co-efficient

 

[Puddle]

the wax cartridge will be broken in the diverter valve
The normal position for the diverter to sit is in the hot water mode position

When heating is called for the water heats in the boiler and there is a wax capsule in the bottom of the diverter valve that expands and pushes the diverter valve open for hot water to flow around the heating side,

 

[tipintim]

Still waiting to find out what NTC stands for
Can you lighten me

 

[londondave]

dunno much about that model, but if your divertor is stuck, when the ch is on the water will go through the dhw x changer and overheat. You should be able to feel the pipework for heat

Cheers, yeah thats pretty much exactly whats going on. pipe between burner to divertor is hot. divertor itself is hot. pipes to heat exchanger hot, one of the pipes from the divertor to the return side pump is hot, but the flow pipe coming out of the boiler is cold. I'm 90 % its the divertore valve, not moving but partly wondering if other factors (like a weak pump) could be something to do with it.

I am also concerned its not getting the right signals/ inputs e.g. the wax stat to move on the diverter. So dont know if the diverter is jammed, or if its not getting the right inputs to move.

Not to sure I want to swap the divertor to find it could be e.g. the wax stat or other....

 

[londondave]

not too sure, its a thermistor (resistance thermometer), but not too sure what it stands for exactly

 

[Puddle]

A NTC is a ' Negative Temperature Coefficient,

Basically a temperature thermistor for the boiler

This boiler was way ahead of its day,boootaful thing,trouble now is getting parts and they are getting very old now

 

[AllyBongo]

Like puddle says, sounds like the wax capsule is a gonner. Wasnt sure what kind of divertor it was. Will the divertor/wax capsule nott be in the one unit??

 

[londondave]

Thanks. That sounds like the answer.

So to confirm.

If the wax capsule is broken you normally get DHW and no Central heating?

Will try and get a new wax capsule and stick this in tommorow night. Will post a response on what the story is tommorow night.

 

[tipintim]

lol. wanted to know if he did

 

[Puddle]

Thanks. That sounds like the answer.

So to confirm.

If the wax capsule is broken you normally get DHW and no Central heating?

correct

Will try and get a new wax capsule and stick this in tommorow night. Will post a response on what the story is tommorow night.

If you look at bottom of divertor valve you will see ,think 3 screws holding bottom section together and think one pipe attached,wax capsul fits in there

Would add ,system like puma,so if there are any taps dripping badly the heating will not change over either as water in boiler will not get hot enough to do so

 

[Pope John 2]

cannot be NTC coz it works in HW
It's hydraulic,

1st remove the left hand side panel (long white bit) then the top of diverter metal cover to see if diverter is UP for HW then goes DOWN for CH
Turn on a hot tap see if piston moves and then tap OFF demand heating does the piston go DOWN
2nd turn OFF electrics on the wall to remove the screws which house the 2 pcbs and the water valve which may be stuck UP in HW mode stopping CH to come on

 

[Puddle]

cannot be NTC coz it works in HW
It's hydraulic,

1st remove the left hand side panel (long white bit) then the top of diverter metal cover to see if diverter is UP for HW then goes DOWN for CH
Turn on a hot tap see if piston moves and then tap OFF demand heating does the piston go DOWN
2nd turn OFF electrics on the wall to remove the screws which house the 2 pcbs and the water valve which may be stuck UP in HW mode stopping CH to come on

Who said it was the ntc ?,op mentioned a test he had done and others asked what what ntc stood for

If hot water micro switches stuck on boiler would be firing all the time

Obviously if wax cartridge is working diverter would move, and can be seen at top of unit

 

[londondave]

Thanks for the good advice.

Bought a reconditioned diverter valve with built in wax cartridge at the bottom. £160 but £50 returned when handing back the old knackered one. Got this from Adlink in London.

Fitted it after a lot of wrestling in a dark small cupboard (took about 3 hours believe it or not trying to angle up the compression fittings without threading them.

Anyway once in the boiler fired up and worked fine for both ch and hot water so result, and a happy cust who paid £320 instead of the 2k quoted for a new boiler.

Thanks

Dave

 

[Puddle]

Pleased you got sorted Dave

Thanks for the feed back

All's well that ends well