Alpha E-Tec 33 - Intermittent Hot Water Issue - Wifi Connection?

[Poppysdad]

Good afternoon chaps,

I have an Alpha E-Tec 33 combi boiler (with Google Nest 3rd Gen thermostat) that occasionally fails to put out hot water. The C.H. works fine (at least I haven't noticed any issues), but in the past 6-9 months or so, when using the thermostatic shower, there's sometimes no hot water.

I've managed to catch the problem twice, and when I do the display on the boiler control panel shows that the boiler is in Standby Mode, rather than the usual Summertime Mode. The buttons on the control panel are not very responsive so it's difficult to do much other than turn it off and on, but this doesn't help. My only option so far is to just wait it out and see when it comes back - usually 10-15 minutes.

My question is this - could this be due to my wifi dropping out and the boiler losing connection with the thermostat? I recently moved the Heat Link out of the boiler cupboard to help with the signal, but the problem happens so infrequently that it's hard to tell if it has helped any.

If it's not the wifi, is there a mechanical/plumbing/controlboard issue that would give the same troubles? What could cause the control panel to switch from Summer to Standby?

Any advice would be gratefully received!

Cheers, PoppysDad

 

[James]

Is it only an issue with the shower? Or do you get the same problem when using a hot water tap?

 

[Poppysdad]

Is it only an issue with the shower? Or do you get the same problem when using a hot water tap?

Hi James,

I'm told it also happens when using the hot water tap. I've never noticed it, but PoppysMum said it happens when she's doing the dishes - read into that what you will.

 

[James]

Most combi boilers have hot water permanently on, they are waiting for a flow switch to activate the heating.
maybe worth a boiler service and asking the engineer about it.

 

[davesparks]

The nest thermostat plays no part in the hot water function of a combi boiler, the thermostat purely controls heating.

If there's a problem with the hot water then this will almost certainly be down to the boiler, the fact the controls are unresponsive also points towards this.

 

[Poppysdad]

The nest thermostat plays no part in the hot water function of a combi boiler, the thermostat purely controls heating.

If there's a problem with the hot water then this will almost certainly be down to the boiler, the fact the controls are unresponsive also points towards this.

Hi Dave,

Thanks for the reply. That makes sense. I may have been blinded by the possibility of a link between the crap wifi in the house and the wireless thermostat to the boiler.

I just downloaded the manual and found the Error History list which showed Error 45 - "High DeltaT" as the most recent, and most frequent error. The manual states - "The boiler detects a sudden, unexpected increase in DeltaT between the flow sensor and the system return sensor", and Possible Cause - "Burner input is limited for boiler protection, and once the right DeltaT is restored, the boiler resumes regular operation. Make sure there is water circulating in the boiler, that the pump is configured according to the system requirements, and that the return sensor is correct." This pretty much tallies up with the symptoms we have seen - no hot water, wait 15 minutes, hot water comes back on again.

I checked the DeltaT parameter and it was set to 15K as is factory default (range between 0K and 25K). I have increased this parameter to 20K, will reset the error history, and monitor for further dropouts.

Can you see any obvious issues with the above? Would you recommend a call-out to explain the issues with a technician? The boiler is serviced every year by the manufacturer's agent, and they have never picked anything up.

 

[davesparks]

Can you see any obvious issues with the above?

Yes, the DeltaT is the design temperature difference between the flow and return pipes of the heating circuit and as such should have no bearing on the hot water function of the boiler.

 

[Poppysdad]

Yes, the DeltaT is the design temperature difference between the flow and return pipes of the heating circuit and as such should have no bearing on the hot water function of the boiler.

But if the boiler detects a DeltaT error and switches to Standby until the DeltaT returns to normal then the HW wouldn't work while the boiler was in Standby, no?

 

[James]

Check you have at least 1 radiator that is on full flow and has no thermostatic radiator valve.

 

[Poppysdad]

Check you have at least 1 radiator that is on full flow and has no thermostatic radiator valve.

Hi James,

That's a new one on me! All the rads had thermostatic valves so I've removed one and left it fully open.

Checking the fault history this morning, almost 48 hours after resetting, there are currently no new faults.

I suppose I just leave things as they are and keep checking.

 

[davesparks]

Check you have at least 1 radiator that is on full flow and has no thermostatic radiator valve.

Not just any radiator though, it should only be the radiator in the room where the thermostat for each zone is located which doesn't have a TRV.