Hot flow and return pipes, hot upstairs rad but cold rads downstairs

[ShaunCorbs]

Yeah I'm not going to go taking the pump apart! Seems odd though that the upstairs rads still get hot relatively quickly if the pump was stuck?

heat rises

 

[Harvest Fields]

heat rises

Was just typing that as well.

 

[Mark Garland]

if it shoots up and doesnt go down within 2-3 mins and boiler doesnt stay lit (fired) then i would say pump could be stuck

Right, just tried again. After turning the thermostat up, temp rose very quickly to 57, then dropped back down to 50 (sounded like pump turned on), then was fluctuating from 55-50 after 1 minute.

After 3 minutes its 57

4 minutes its 59

5 mins its 62 (boiler still fired)
7 mins in its 66

So, does seem to be rising slowly.

I am heating a click sound every so often (every 10-30 seconds) not sure if that is important.

 

[ShaunCorbs]

i would say thats fine then

 

[Mark Garland]

heat rises

Yeah I get that but surely it cannot rise that fast? Or is it the hot water rises to the top of the circuit so kind of pushes itself round?

I will try our gas engineer first but failing that will give Vaillant a ring.

 

[Harvest Fields]

i would say thats fine then

The integral may need setting up properly

 

[Mark Garland]

One other thing, if the pump was stuck but the rads get hot upstairs because the hot water rises, why is the return pipe still piping hot?

 

[Harvest Fields]

One other thing, if the pump was stuck but the rads get hot upstairs because the hot water rises, why is the return pipe still piping hot?

The pump could be spinning but not on full rate. Modern pumps are supposed to modulate dependant on demand.

 

[ShaunCorbs]

so all your down stairs rads arnt working

 

[Mark Garland]

so all your down stairs rads arnt working

Correct, not a single one