Upstairs rads getting hot, downstairs not at all.

[justanotherguy]

I probably need a professional for this, but can anyone help me narrow it down, so I don't get completely fleeced please!

From what I can gather from searching, it looks like it could be sludge and/or pump failure.

With the combi set to 65C rad flow temp, I see it cycle from about 50C to 75C in 60 seconds, and then the flame symbol turns off while the rad symbol flashes. I believe this means the heat isn't being distributed properly, hence the frequent cycling of the boiler?

I've tried turning off all the upstairs rads, but it doesn't seem to have helped downstairs.

 

[gas112]

what make and model of combi .
Also if your topping up taps are under the boiler check that you havent accidentally partially turned off the boiler isolating valves

 

[Harry Bloomfield]

From what I can gather from searching, it looks like it could be sludge and/or pump failure.

It does help you much, but your diagnosis is likely correct!

 

[justanotherguy]

what make and model of combi .
Also if your topping up taps are under the boiler check that you havent accidentally partially turned off the boiler isolating valves

Thanks.

It’s a Vaillant ecoTec plus 837

The valves underneath have grey tabs facing the front of the boiler saying “closed”.

The CH flow out is hot to the touch.

 

[CountryFan]

Thanks.

It’s a Vaillant ecoTec plus 837

The valves underneath have grey tabs facing the front of the boiler saying “closed”.

The CH flow out is hot to the touch.

Can you post a photo of these? Also, could be a failing diverter valve.