Vaillant Ecotec plus 428 No heating

[Vespertinestar]

Hi

We've got a Vaillant ecotec plus 428 that doesn't seem to want to supply any heat to the radiators despite the hot water working just fine.

Of some importance (I think) is that there is no radiator symbol displayed on the boiler screen, only a tap.

We have a wireless thermostat (Altech ALTHC015) with fresh batteries calling for heat connected to a box displaying a red and green light which I believe means power and connectivity are fine.

I have so far tried turning everything off including the Honeywell ST9400C controller and removing the batteries to reset anything that might be causing a bug as last year it turned out the wireless thermostat had just bugged and resetting it worked fine.

The boiler displays s30, indicating no call for heat. Manually firing the boiler does not make the radiator symbol appear and they don't get warm.

Any advice would be greatly appreciated.

Warmest regards, Matt

 

[Deleted member 120897]

Is there an override on the thermostat? Try this. Could be a faulty motorised valve, or could be the thermostat. Do you have any test gear?

 

[Vespertinestar]

Is there an override on the thermostat? Try this. Could be a faulty motorised valve, or could be the thermostat. Do you have any test gear?

Thanks for your reply. There doesn't appear to be anything on the Altech unit to override; on the Honeywell controller there is an override button and I can set it to run continuously (If that's what "Cont" means in this context) but no luck on either. What would you define as test gear?

Warmest regards, Matt

 

[cjg]

how-to-rf-code-rt300rf-althc015.pdf - Hecas​

does this help

 

[Deleted member 120897]

What would you define as test gear?

Warmest regards, Matt

A multimeter or 2 pole voltage tester.

 

[Basher]

If the receiver green light is on, that shows the communication is working.
Do you know what is happening with the motorised valve(s)?
You appreciate (I believe for your system) the Altech controls the motorised valve, and within the motorised valve is the switch that calls for heat from the boiler. If the valve is not moving that switch won't be operating.

 

[Vespertinestar]

If the receiver green light is on, that shows the communication is working.
Do you know what is happening with the motorised valve(s)?
You appreciate (I believe for your system) the Altech controls the motorised valve, and within the motorised valve is the switch that calls for heat from the boiler. If the valve is not moving that switch won't be operating.

Thanks for your replies. I've looked into the motorised valves and I've found two of them. Both can be moved using the manual bit on the back fully over to one side and back again. Should there be anything outwardly obvious happening with the valve when it is operating?

I have a multimeter so I can test things if required.

The controller appears to be connecting to the boiler just fine as the boiler displays when the pump is running.

Whilst I am here I have another question to add. We have always had, since we moved here, an issue with the boiler constantly cycling e.g. rapidly heating up to 70 degrees within several seconds and then shutting down with a flashing radiator symbol for a few minutes before firing again; is this anything I can change? I've got it on video, if anyone wants to take a look I'll upload it.

Warmest regards, Matt

 

[ShaunCorbs]

Need to link out the heating thermostat

 

[Vespertinestar]

Need to link out the heating thermostat

Could you explain further?

Warmest regards, Matt

 

[ShaunCorbs]

On the reciever need to check if it’s outputting live / call to the system as it could be just the room stat is dead

 

[Deleted member 120897]

You need to find the wiring center and put the heating on.

Then find the live from the thermostat to the brown wire for the heating motorised valve, test (on voltage ac) between neutral/earth and the brown (live) and the reading should be 240vac or close to it. If that is good then proceed to test between neutral/earth and orange and should have 240vac.

If you don’t get 240vac on the neutral and brown, then it could be a dead room stat.

 

[Vespertinestar]

Thank you so much for your replies so far, they've been very helpful as with your assistance I've narrowed it down to the wireless room stat being faulty; once this is bypassed the heating works. Can anyone tell me what the best replacement (same functionality) for the mentioned above thermostat and controller would be?

Warmest regards, Matt

 

[ShaunCorbs]

I use eph combi pack 4

 

[Deleted member 120897]

Can anyone tell me what the best replacement (same functionality) for the mentioned above thermostat and controller would be?

Warmest regards, Matt

There’s literally 100’s on the market, just stay clear of the same one as yours, Salus or Secure/Horstmann.

 

[Vespertinestar]

There’s literally 100’s on the market, just stay clear of the same one as yours, Salus or Secure/Horstmann.

Ah, okay thanks for the heads up as I was perhaps looking at the Salus rt310rf as a fairly direct replacement but if they're no good I'll keep looking. The combi pack 4 looks great but has a lot of extra functionality I don't really need at the moment, thank you for the suggestion though, it remains on my shortlist.

Warmest regards, Matt

 

[Deleted member 120897]

Ah, okay thanks for the heads up as I was perhaps looking at the Salus rt310rf as a fairly direct replacement

Altech are made by salus. Have a look at Esi or Heatmiser.

 

[Vespertinestar]

Altech are made by salus. Have a look at Esi or Heatmiser.

Thank you all so much for your replies. I have replaced the thermostat and the heating works again, ready for winter, when we will not be able to afford to turn it on 🤣

Warmest regards, Matt