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

[Mark Garland]

As in the title, the flow and return pipes both get hot when the heating is turned on, yet only the upstairs radiators get hot.

I am very puzzled by this. Even turning off all thermostatic valves upstairs, none of the downstairs rads get hot. Our plumber says there must be a blockage looking for a second opinion. Not sure how there can be a blockage if the return is still hot.

Any help would be appreciated.

Mark

 

[Harvest Fields]

How old is you pump and what boiler do you have mate?

 

[Mark Garland]

How old is you pump and what boiler do you have mate?

It's a Vaillant ecoTEC plus 835. Is brand new, was installed in May 2018. Had been working great for the last few months, then we've had the heat off while its been warm but now is cooling down so heat back on and this problem has appeared.

 

[Harvest Fields]

It's a Vaillant ecoTEC plus 835. Is brand new, was installed in May 2018. Had been working great for the last few months, then we've had the heat off while its been warm but now is cooling down so heat back on and this problem has appeared.

Thermostats on all the downstairs radiators?

 

[Mark Garland]

Thermostats on all the downstairs radiators?

Yep and all turned up to max.

 

[Harvest Fields]

Yep and all turned up to max.

Remove the heads and make sure that the pins have not seized in the off position .

 

[Mark Garland]

Remove the heads and make sure that the pins have not seized in the off position .

They were never turned off and worked until 2 months ago the thermostats on the downstairs rads havent been touched, just left on max. Also seems unlikely to me that tall of them would break at exactly the same time?

 

[Harvest Fields]

was the boiler a combi before or conventional?

 

[Mark Garland]

was the boiler a combi before or conventional?

Always been a combi

 

[ShaunCorbs]

sorry mark

 

[Harvest Fields]

sorry mark

It’s not your fault mate. Hopefully Mark can see that.

 

[Mark Garland]

sorry mark

thanks for deleting the spam mate, some people really have nothing better to do!

 

[Harvest Fields]

Always been a combi

I would say it is time to get the engineer out back mate. Nothing else you can do without looking more in depth at the boiler.

 

[ShaunCorbs]

thanks for deleting the spam mate, some people really have nothing better to do!

it gets frustrating trying to kock them back two more pop up

 

[ShaunCorbs]

right back to business how fast does the temp rise on the boiler?

 

[Harvest Fields]

it gets frustrating trying to kock them back two more pop up

A MODS work is never done Shauny boy

 

[Mark Garland]

I would say it is time to get the engineer out back mate. Nothing else you can do without looking more in depth at the boiler.

Ok will do. Considering that the flow and return both get very hot do you think a blockage is still possible though? Just doesn't seem like that would be the cause if that is the case...

 

[ShaunCorbs]

A MODS work is never done Shauny boy

esp for one mod

 

[Harvest Fields]

esp for one mod

Is it still just you. Lou and Dan?

 

[Harvest Fields]

Ok will do. Considering that the flow and return both get very hot do you think a blockage is still possible though? Just doesn't seem like that would be the cause if that is the case...

Possible but could be a few other things that I am not allowed to tell you how to check. (Sorry)

 

[Mark Garland]

right back to business how fast does the temp rise on the boiler?

Pretty quickly, I watched it earlier and hit full operating temp for heating after a few minutes and all upstairs rads nice and hot quite quick.

 

[ShaunCorbs]

could be pump stuck happens with the new eco pumps but need to be gas safe to have a look

 

[Harvest Fields]

Pretty quickly, I watched it earlier and hit full operating temp for heating after a few minutes and all upstairs rads nice and hot quite quick.

Should be a gradual rise mate.

 

[Mark Garland]

Possible but could be a few other things that I am not allowed to tell you how to check. (Sorry)

No worries, it's just the boiler has a warranty but I don't want our plumber to try and go around it by blaming the problem on our pipes.
We haven't got much experience with them so still building up trust so don't want to be given the run around hence asking on here.

 

[Mark Garland]

Should be a gradual rise mate.

Hmm, I could time it, what time frame should it be?
May have underestimated it last time, time flies when you're having fun staring at a temperature guage

 

[ShaunCorbs]

get Vaillant out there have a decent set of lads

 

[Harvest Fields]

No worries, it's just the boiler has a warranty but I don't want our plumber to try and go around it by blaming the problem on our pipes.
We haven't got much experience with them so still building up trust so don't want to be given the run around hence asking on here.

Your first point of call should always be your gas engineer. But if you have lost faith then go straight to Vaillant. They are generally really helpful and if you have warranty they will come out and have a look.

 

[Mark Garland]

could be pump stuck happens with the new eco pumps but need to be gas safe to have a look

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?

 

[Harvest Fields]

get Vaillant out there have a decent set of lads

Two great minds... well one anyway

 

[ShaunCorbs]

Hmm, I could time it, what time frame should it be?
May have underestimated it last time, time flies when you're having fun staring at a temperature guage

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

 

[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.