Vaillant Turbomax Plus 828 hot water problem

[David937]

Hi all,

Having some issues again with the Vaillant Turbomax boiler which is now 11 years old.

When you open any hot water tap, the boiler seems to ignore the demand and remain off, if you press 'i' you get the code S.30. If you leave the tap open for a while it eventually comes on but only for a short period before switching off again, when it does come on, the water is nice and hot and at a constant temperature and when it goes off, the pump overrun will time out and the boiler will go back to S.30 (no heat demand)

The green light doesn't flash when hot water is being requested.

I checked that the heating is working and this works normally as it should.

Any ideas on what the problem is?

 

[David937]

I have just read up a bit more on this issue; as it is not recognising the hot water demand, could it be the Aqua sensor?

 

[Agile]

That would be the first part to check!

But I thought you had a 937 ???

Tony

 

[David937]

That would be the first part to check!

But I thought you had a 937 ???

Tony

Yes I do have a 937 but this is my nans boiler which I have posted about before.

Is this part tricky to remove and will it require me to drain the boiler? I had a bad experience when I cleaned the plate heat exchanger as the drain valve snapped and consequently leaked afterwards.

 

[Agile]

Only need to turn off cold water in.

But if awake, you would have known that anyway!

 

[David937]

Only need to turn off cold water in.

But if awake, you would have known that anyway!

Yeah I thought I may have to remove the plate heat exchanger for better access.

 

[GuessMan]

Morning David,

Keep looking at the status codes, when the hot water works, does the code start with a 2? If so it is firing on hot water preheat. If this is the case, it won't be seeing the aquasensor. There are three faults to check:

1 the turbine isn't spinning - isolate supply and remove with circlip pliers and clean.
2 hall sensor faulty or out of it's socket.
3 loom damaged - get your meter out and check continuity

Have never changed the whole aquasensor, just swapped bits on to the existing brass body.

Btw how is the old dog 937? Has it had a new shunt pump yet?

 

[David937]

Morning David,

Keep looking at the status codes, when the hot water works, does the code start with a 2? If so it is firing on hot water preheat. If this is the case, it won't be seeing the aquasensor. There are three faults to check:

1 the turbine isn't spinning - isolate supply and remove with circlip pliers and clean.
2 hall sensor faulty or out of it's socket.
3 loom damaged - get your meter out and check continuity

Have never changed the whole aquasensor, just swapped bits on to the existing brass body.

Btw how is the old dog 937? Has it had a new shunt pump yet?

Hi, thanks for your reply. I will check this when I next see the boiler, unfortunately I don't have a meter so can't do 3! In fact, the water only does work shortly when it is on pre-heat and I am pretty sure the code was S27 or something when it was on.

The 937 is doing just fine, still on its original shunt pump which is nearly 4 years old

 

[Agile]

No test meter?

Why on earth not?

Its the second most important tool of all for boiler repairs!

 

[David937]

No test meter?

Why on earth not?

Its the second most important tool of all for boiler repairs!

Afternoon Tony, I understand it is important but I don't repair boilers for a living and I don't intend on doing so either. If something it is out of my scope, I get an RGI in.

 

[Agile]

So what do you intend to do then?

Having and knowing how to use a test meter is useful for so many things!

Tony

 

[David937]

So what do you intend to do then?

Having and knowing how to use a test meter is useful for so many things!

Tony

If you want to discuss this then I prefer you email me or PM me.

 

[GuessMan]

S27 is hot water preheat overrun, so lok at 1 & 2.

Why aren't you in the CC yet? I knew you in a previous carnation! Kevin told me to go lite on you, you were training to be a RGI. What happened.

I hope you haven't given up; not great in my world at the moment, but I'm still surviving.

 

[David937]

Forgot to update this thread in case anyone comes accross it in the future.

The problem was a faulty hall sensor which cost under £20 to fix and took very little time.

Thanks for the help.