Vaillant TurboMax Plus 824E

[kevingrng]

Combi Boiler: The problem Iam going thru with Vaillant TurboMax Plus 824E My issues started 4 weeks back, problems with the boiler cutting out after a few minutes. Hot water perfectly fine . The problem we are having is with the central heating side. The boiler starts up and makes the usual noises. The flames light and remain lit for around 2 minutes, after going off. The boiler continues to make the noise those (as though it is fully working). After about another 5 minutes the flames light again for another 2 minutes (It doesn't reach the temperature-It gradually goes upto 30c and cut off the heating. When the temp gradually reached 18c it starts again for few minutes and cut off. This cycle continue until I turn off the CH. Well after running for couple of hours radiator gets warm at the bottom only. ( All rads bleed) I thought could be room thermostat. I have changed two thermostats from different brand but NO luck. FYI-Its nearly 20 years old combi boiler.
Boiler shows NO Fault Code.

 

[CBW]

Sounds like a restriction or it’s not making on heating demand.

 

[kevingrng]

@CBW thanks for reply. I forgot to mention when i press i it show S7(Pump overrun). I have been trying to find a parts if boiler required but no luck finding any answer.

 

[CBW]

@CBW thanks for reply. I forgot to mention when i press i it show S7(Pump overrun). I have been trying to find a parts if boiler required but no luck finding any answer.

S7 is heating pump overrun. That’s just the status code, which at this stage is irrelevant. What needs to be established: is the diverter or microswitch/pump proving switch making? Is it an external control fault?

 

[dilalio]

What condition is the system water in?
Has it ever been checked, drained, flushed, inhibited?

 

[kevingrng]

Hi Dilalio, I have checked all the water inlet drained and flushed including bleeding rad. I got no options left than to run temp on flhs mode.

 

[dilalio]

Hi Dilalio, I have checked all the water inlet drained and flushed including bleeding rad. I got no options left than to run temp on flhs mode.

So you drained the CH?
What colour/state was the water you drained out?

 

[kevingrng]

S7 is heating pump overrun. That’s just the status code, which at this stage is irrelevant. What needs to be established: is the diverter or microswitch/pump proving switch making? Is it an external control fault?

I'll check diverted valve. Sorry CBW to be d**k asking stupid questions. what actual component external control fault we are looking for? Thanks

 

[dilalio]

Boiler is overheating and cycling.
There are various reasons for this.
Heat is not getting away.
Dirty treacle-like system water;
Lazy or kaput pump:
Flow sensors not switching pump on;
Temp sensors not reading delta properly.
Diverter not opening.
Hex blocked.

 

[kevingrng]

So you drained the CH?
What colour/state was the water you drained out?

Thank you for your reply. Dilalio to be honestly speakjng other end of of the connector face to garden( it was dark and thought not important) I'll do it today.

 

[kevingrng]

Boiler is overheating and cycling.
There are various reasons for this.
Heat is not getting away.
Dirty treacle-like system water;
Lazy or kaput pump:
Flow sensors not switching pump on;
Temp sensors not reading delta properly.
Diverter not opening.
Hex blocked.

Dilalio, thank you for your help. I'll try all your possible cause you mentioned.

 

[CBW]

I'll check diverted valve. Sorry CBW to be d**k asking stupid questions. what actual component external control fault we are looking for? Thanks

A time clock, thermostat - these are what control the heating

 

[kevingrng]

Second link can skip..