Vaillant ecoTec Plus 624 not heating radiators, hot water fine

[Paddyx]

We have a three year old Vaillant ecoTec Plus 624 which is producing plenty of hot water but has stopped heating the radiators and towel rails. It had been working fine before that.

When the boiler is on I can hear it firing. The water pressure is 1 bar. The control unit is a wifi VR 66. I have changed the batteries in the control unit and the thermostat seems to be working. Neither the boiler nor the control unit are showing any error messages.

Nothing was touched or changed on the system before it stopped heating the radiators. For testing I have the thermostat set as high as it can go (30 C) and I have the controlled in a cool place so that it is recording an ambient temperature of 24 C.

I have vented all the radiators, the towel rails and the Fernox filter a couple of times. I can't find any external pump to vent and I am wary about opening up the boiler to see if I can vent the internal pump in case I void the warranty. I have flushed out the filter.

I have been trying to get the boiler working when there has been nobody else in the house and so no hot taps running or dishwashers etc running to cause an override on the heating.

One thing that I have noticed is that the pipe above the filter is very warm and the filter itself is warm but the pipes below the filter is cold. Is this how it should be? Both valves above and below the filter are set to on (parallel with the pipe).

Is there anything else that I can try before calling in the heating engineer?

 

[ShaunCorbs]

Do you have weather comp installed any may I ask why your turning the heating on in this weather?

 

[Paddyx]

There's no weather compensation system that I can see. I've also checked the installers invoice and there's nothing that looks like an item for that type of system. We have the radiators off but run the heating for and hour or so a day for the towel rails.

 

[ShaunCorbs]

Ok

turn the prog on for hot water once the boilers fired turn it on for heating also (turn the room stat up all the way if you've turned it back down again) do the rads get warm ?

 

[Paddyx]

Thanks for the suggestion. I have run the hot water tap until the boiler kicks in and then turned the heating on (with thermostat turned all the way up). Still no heating and the pipes running into the radiators are still cold.

 

[Harvest Fields]

We have a three year old Vaillant ecoTec Plus 624 which is producing plenty of hot water but has stopped heating the radiators and towel rails. It had been working fine before that.

When the boiler is on I can hear it firing. The water pressure is 1 bar. The control unit is a wifi VR 66. I have changed the batteries in the control unit and the thermostat seems to be working. Neither the boiler nor the control unit are showing any error messages.

Nothing was touched or changed on the system before it stopped heating the radiators. For testing I have the thermostat set as high as it can go (30 C) and I have the controlled in a cool place so that it is recording an ambient temperature of 24 C.

I have vented all the radiators, the towel rails and the Fernox filter a couple of times. I can't find any external pump to vent and I am wary about opening up the boiler to see if I can vent the internal pump in case I void the warranty. I have flushed out the filter.

I have been trying to get the boiler working when there has been nobody else in the house and so no hot taps running or dishwashers etc running to cause an override on the heating.

One thing that I have noticed is that the pipe above the filter is very warm and the filter itself is warm but the pipes below the filter is cold. Is this how it should be? Both valves above and below the filter are set to on (parallel with the pipe).

Is there anything else that I can try before calling in the heating engineer?

What filter do you have fitted? Can you take a picture of it and the valves attached to it.

Edited for spelling errors

 

[Darren Jackson]

I think this is a system boiler (correct me if I am wrong). Therefore it is unlikely to be a boiler fault given it is only 3yr old. If it is a newish boiler but older controls and motorised valves It is more likely to be the motorised valve on the CH circuit that is faulty, usually found in the airing cupboard next to the hot water cylinder. It could be a 2 port S plan system so check that the pipe is getting hot on both sides of the motorised valve. or it could be a 3 port Y plan and again check that the pipe is getting hot on the heating side of the valve. You could try moving the small lever at the side of the valve and lock it into place by hooking it into the open position and see if the radiators heat up, this will confirm if it is working or not. either way you could really do with employing a GSR to check it out for you.