Vaillant ecotec 438 overheating on HW

[noddy997]

Hi all the vaillant ecotec 438 is overheating when HW is on

HW only - If flow set to 60c it goes up to 80c

It's fine on CH

When both CH and HW on together it will go up an extra 10c

Here's a video with it on HW only

 

[cross thread]

Probably a secondary heat exchanger issue
apologies though it was a combi ,ignore my comment

 

[noddy997]

Probably a secondary heat exchanger issue

Boiler does make a water gulping sound when I switch between HW and CH and some of the pipes making clanging noise too but 3 port valve is very far from the boiler up in the loft

 

[MNW67]

Boiler does make a water gulping sound when I switch between HW and CH and some of the pipes making clanging noise too but 3 port valve is very far from the boiler up in the loft

Is this a new problem? Or could it have been going on for ages and you've only just noticed it?

Am I right in thinking this is a regular heat only boiler?

What does the dial with the tap symbol on actually do? Does it do anything?

 

[noddy997]

Is this a new problem? Or could it have been going on for ages and you've only just noticed it?

Am I right in thinking this is a regular heat only boiler?

What does the dial with the tap symbol on actually do? Does it do anything?

A new problem.

Heat only boiler, that dial does nothing

 

[Johntheo5]

Is It a sealed or open vented system, if sealed, check pressure is 1 bar cold, minimum, if OV, check that feed and expansion cistern in the attic is "full", around a 1/3rd or so.

 

[Johntheo5]

I thought I remembered the name, it all goes back to this??.

Grundfos ups3 making noise

Bleeding: You just press the button on the front once and within 5 seconds it will do some fancy footwork like speeding the pump up and down for 10 minutes or so, if you press it twice it will do something similar after 5 secs, for 10 minutes, I've installed three or four (6M) for relations and...

www.diynot.com

You now have a 6M Wilo Yonos Pico, what mode/setting and power output and flowrate is it showing, you found the almost brand new UPS 3 full of crap, also the magnetic filter, have you checked/cleaned them out/.

 

[noddy997]

I thought I remembered the name, it all goes back to this??.

Grundfos ups3 making noise

Bleeding: You just press the button on the front once and within 5 seconds it will do some fancy footwork like speeding the pump up and down for 10 minutes or so, if you press it twice it will do something similar after 5 secs, for 10 minutes, I've installed three or four (6M) for relations and...

www.diynot.com

You now have a 6M Wilo Yonos Pico, what mode/setting and power output and flowrate is it showing, you found the almost brand new UPS 3 full of crap, also the magnetic filter, have you checked/cleaned them out/.

Hahaha how you doing?

It's on constant curve highest setting.

Yes magnetic filter cleaned a few times and last time I added inhibitor to it and that immediately helped this new issue.

 

[stem]

If it's working ok for CH but not HW to me that suggests that there may be is insufficient water flow when the HW only is on.

Is there a restriction in the HW circuit. Usually there is a balancing valve on the HW return, has it inadvertently been closed too much?

Anything happen just before the problem occurred, any work being done elsewhere, anything been changed?

 

[noddy997]

If it's working ok for CH but not HW to me that suggests that there may be is insufficient water flow when the HW only is on.

Is there a restriction in the HW circuit. Usually there is a balancing valve on the HW return, has it inadvertently been closed too much?

View attachment 338138

Anything happen just before the problem occurred, any work being done elsewhere, anything been changed?

Nothing at all