Vaillant Ecotec plus 630 no heating hot water

[RMS786]

Hello forum members.

I am new to this forum.

I have a pressurised unvented system. Vaillant ecoTec plus 630 system boiler with telford tempest 300l tank. Turned on the heating a couple of weeks ago and found that the upstair radiators were not heating up. Went round bleeding the upstairs radiators without realising that the boiler pressure was at the lower end of operating limit. Bleeding the radiators resulted in the upstair radiators heating up. All well and good. Following morning no heating and hot water. Boiler displayed F22 fault code (0.7 bar). Topped-up the pressure to 1.2 bar and this resulted in boiler firing up, pump coming on. However the temperature of the boiler quickly rose to 84 degrees and then the pump went into overrun mode. CH Pipe further down the 2 port motorised valve was luke warm. Assuming this was something to do with motorised valve malfunction. Removed the valve head and can turn the valve spindle with hand without any resistance. Have the same situation with the 2 port HW motorised valve as well. At present, i have run out of things to try. I will post a photo of the setup with description shortly.

Many thanks in advance for guidance in resolving this.

Thanks

 

[terryplumb]

Lack of circulation ,try bleeding the pump it may be full of air.

 

[RMS786]

Thanks a lot Terry. How do i bleed the pump?This model has upm3 15-70 Grundfos pump.

 

[terryplumb]

That pump should purge itself of air if you let it run.
Have you vented air from the system ,all radiators ,cylinder coil ,any manual bleed valves at high points anywhere ?

 

[RMS786]

I have drained water ftom the cylinder coil and bled all the radiators. Do not believe there is air anywhere in the system. There is an external expansion vessel fitted on top of the cylinder. I had fully drained down the system and bled air from the radiators systematically. I have turned on the boiler again and see a sand clock appearing and the pump running for a short while begore cutting off.

 

[RMS786]

Failed to mention in my previous post that i used the access screw on the pump face to turn the pump. I then turned the heating on and while the behaviour is still the same but feel that half a metre of pipe downstream of CH 2 port valve or so is almost the same temperature as upstream of this valve. Bit lost on what to do next. Our builder, who also installed this heating system has duped us of money and has gone awol. So, completely skint at present and cannot afford a plumber/heating engineer visit to resolve this. Any help resolving this will be much appreciated.

 

[terryplumb]

At what point did you fully drain the system , after you experienced problems with the boiler temp rising quickly to 84 degrees ?
If you set demand for domestic hot water and central heating ,does boiler temp still rise quickly to 84 c ?
Have you closed any of the boilers valves ,flow or return ?

 

[RMS786]

Yes i drained the whole system after i experienced the boiler temperature quickly rising to 84 degs.

Yes, the boiler temp still rises very quickly to 84 degs with both heating and hot water on. I have not touched any other valves except the two valves on the filling loop to re-pressurise the system.

 

[RMS786]

 

[RMS786]

Posted a few photos. Happy to provide description if required.

 

[picasso]

Did you open the air vent just above the pump ?

 

[RMS786]

Is it the little grey cap behind the connector on the pump in the first photo? I do not recall touching it. Does it need to be like half a turn or so of being thumb tight? I have double checked and it is about a quarter to half a turn of being thumb tight. Does the pressure on the guage next to the pump look ok? What is the little red lever thing to the right if the pump for?

 

[terryplumb]

Increase the system pressure to 2 bar.
Then switch off electrics to isolate the boiler.
In the centre of the pump is a hole ,using a no 2 Phillips screwdriver ,into the hole ,push into the pump and rotate the screwdriver several turns whilst still pushing inward . This will manually spin the pump .
Then switch electrics back on and turn Ch on.
The heat being generated by the boiler is not being dispersed ,that has to be a fault in the pump ,or air present in the pump or boiler internals.

 

[terryplumb]

By the way keep an eye on the pressure ,if boiler runs ok now ,you may need to switch it off and release pressure back to normal level around 1.2 bar.

 

[RMS786]

Thanks Terry for your response. I have followed your instructions, turned the pump a good 20 odd revs. The situation has not changed. Pump goes into overrun (as per live monitoring) in a minute or two which i take is expected to disperse the heat. The hot water flow out from the boiler is hot until the T joint (image 3 left pipe out of boiler) just above the valves. Sometimes it gets hot up until the valves. Still feel it is a circulation issue, i take the internal and external expansion vessel pressure doesn't come into play with this. Aah, one thing to point out here is that there is an immersion heater in the telford tempest sealed tank. When i switch the boiler off at the mains and switch the immersion heater on for a fair few hours, the flow out pipe from the boiler is hot and radiators upstairs are luke warm. I suppose this re-enfirces that the issue is inside the boiler somewhere?