Loads of air in central heating.

[Chris12345678]

I’ve remembered:
Only thing I did was fit two Z-Wave thermostats (just changed the plastic part of the TRV, didn’t change the actual metal valve), at the beginning of December.

And a few months back I put the CH pump from speed 1 to speed 3.

 

[Harvest Fields]

The pump on 3 might be the issue.

 

[Mdljk]

The pump on 3 might be the issue.

Agree. Try turning down to 1 - temporarily - and wait to see if this has any effect. TRV heads are not an issue.

 

[Harvest Fields]

Why did you turn it from 1 to 3?

 

[Chris12345678]

I changed the pump years ago, at the time I didn't realise it had different speeds. I was trying to improve flow as three radiators are always a bit slow to warm up, they are on the same leg.

 

[Chris12345678]

I held a bowl over the flue for maybe 30 seconds this afternoon, and this is what was in the bowl.


https://i.*********/PwP5IfZ.jpg

https://i.*********/uYVNOtG.jpg

 

[ShaunCorbs]

That’s fine

 

[Mdljk]

Undertandable but you can improve heat up time for slow rads by ‘balancing’ them. Has reducing the pump speed affected water liss from the system?

 

[Chris12345678]

That much water from the flue is ok?

 

[Mdljk]

Yes.

 

[Chris12345678]

Undertandable but you can improve heat up time for slow rads by ‘balancing’ them. Has reducing the pump speed affected water liss from the system?

There is a 15mm leg that runs down from upstairs, there are three reasonable size radiators on this. These are slow to warm up (lounge / dining room), I was trying to improve these.

The other radiators have the valve (not the TRV) adjusted to different positions to control how they warm up 🙂

 

[Harvest Fields]

There is a 15mm leg that runs down from upstairs, there are three reasonable size radiators on this. These are slow to warm up (lounge / dining room), I was trying to improve these.

The other radiators have the valve (not the TRV) adjusted to different positions to control how they warm up 🙂

Theres the issue for them rads not heating. 3 rads on one leg??

 

[Chris12345678]

I've not had a chance to test it with the pump on 1 yet!

 

[Mdljk]

Hot water likes to go up. So upstairs rads often heat up easier than downstairs. For that reason you can balance all the upstairs ones by closing the lockshield entitely and then opening say 1/3 of a turn only. That shoukd not adversly affect the upstairs rads but the downstairs rads will now have more heat diverted to them.

 

[Chris12345678]

Hot water likes to go up. So upstairs rads often heat up easier than downstairs. For that reason you can balance all the upstairs ones by closing the lockshield entitely and then opening say 1/3 of a turn only. That shoukd not adversly affect the upstairs rads but the downstairs rads will now have more heat diverted to them.

I didn't know about upstairs heating up quicker, thanks!

 

[Mdljk]

A common misconception is that rads dont need balancing as TRVs take care of that. They dont but modern systems can get away with it. Yours is an old type system and boiker and system will benefit from balancing

 

[Harvest Fields]

A common misconception is that rads dont need balancing as TRVs take care of that. They dont but modern systems can get away with it. Yours is an old type system and boiker and system will benefit from balancing

Who says this?

 

[Mdljk]

Which part Harvestfields?

 

[Harvest Fields]

The first sentence mate. I was always told that all systems should be balanced.

 

[Mdljk]

Me too. But there is a tendency to believe that because TRVs close rads down individually that balancing isnt as important as you and I both know that it actually is - hence my use of “misconception”