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