Can't get return temp down, are those rads / pipe (photos) the problem?

[BlueLoo]

You haven't explained what you think sludge is doing to cause him a problem.

I don't need to.
It hinders heat flow

Common, don't be awkward.

 

[JohnD]

I do.

Obviously not.

 

[BlueLoo]

Obviously not.

Give over. You'd struggle to give me a definition of it for starters.

The Op is complaining about the house not heating up fast enough. You can go round turning radiators down if you think that was the solution but I'd be left wondering wtf you were doing.

You may be though, probably correct. The rads may be undersized. Maybe not.
Maybe they are full of crud.
Maybe the boiler and it's control is arse backwards.
Maybe he lives in a barn or a field with the gate open.

Before you go prescribing chemo for the patient, lets find the lumps first eh?

It's a heat loss gain problem.
Make sure the system (plumbing) is working first before doing anything else.

Lest that's what I'd do.

 

[Matt723]

Thank you both for your input.

Controls is standard vr65 with ebus.
Arguably the house does leak a bit but it is terraced with recent extensions so roof should be insulated up to regs from last few years. Front and back facade and kitchen return will be solid 2 bricks though the point is before I was in semi detached with similar construction and it used to heat a lot quicker, especially in the room with the 3 columns cast iron rads.

Ill look into sludge / balancing but my gut tells me you are both right on the undersized rads.

Only way to find out is to swap one of them for bigger I guess and see if room heats quicker?

 

[JohnD]

Look for a whole-house heat loss calculator. I can't find a good one now. There are room-by-room radiator size calculators which are not your first choice.

Ed

This might do. Don't tell it your real name and address.

Sutherland Tables web app

 

[JohnD]

I just trialled it, and it came out about 20% low for me (I have used others)

I work on a frosty night of -5C outside and 20C inside, which is a 25degree difference. It might be designed for 20 degrees.

IME housebuilders commonly provide undersized radiators which they claim meets the design requirements. This increases their profits.

 

[BlueLoo]

You haven't explained what you think sludge is doing to cause him a problem.

In video:

 

[JohnD]

You still haven't explained in what way you think the OP is suffering the effects of sludge.

Perhaps you should give up.

 

[BlueLoo]

You still haven't explained in what way you think the OP is suffering the effects of sludge.

Perhaps you should give up.

PErhaps you should read my posts a bit more.
Why are you being obtuse and repeating sludge?

 

[Madrab]

I wouldn't worry about trying to obtain a specific 10deg return to the boiler at the moment. The primary objective is for you to be able to heat the house up properly.

As suggested by @JohnD , if your radiators are getting hot enough, over their whole area and their temps are close to the flow temp from the boiler but the room/house isn't warming up properly then the radiators simply can't be large enough or they aren't efficient enough (non convecting) to replace the heat that the space loses. If that's the case then there will always be slow heat up times.

These days, balancing is pretty important due to uneven distances to each rad, unequal lengths/sizes of the pipe that typically run to them and other additional rads and pipework being added. The aim of an efficient central heating system is to try and get all the rads up to the desired temp, as quickly and evenly as possible. Once that is achieved then finer flow balancing allows the heat loss across the rad to be adjusted to try and achieve a return temp to the boiler as low as possible to maximise condensing, this maximising boiler efficiency. Once the space achieves the target temp then the return temps will rise, lowering efficiency but at that point then the stats should be shutting down the boiler. If the return temps at the boiler rise because of an unbalanced system and the space isn't at the target temp then efficiency can drop.

 

[Jurassicspark]

I don't agree with balancing in modern systems. The trades are addicted to it.

Are you sure about that mate?

You've even said before that there is no need to touch ANY of the lockshield valves, if you've got TRV's installed..

I have bi-directional (wiser) TRV's installed, and yesterday i had found that 1 of the rads were not heating up properly, so what I did was i increased the flow to the rad by turning up the lockshield valve a bit.. and guess what happened? It made the radiator, from lukewarm to blazing hot!

 

[BlueLoo]

Are you sure about that mate?

You've even said before that there is no need to touch ANY of the lockshield valves, if you've got TRV's installed..

I have bi-directional (wiser) TRV's installed, and yesterday i had found that 1 of the rads were not heating up properly, so what I did was i increased the flow to the rad by turning up the lockshield valve a bit.. and guess what happened? It made the radiator, from lukewarm to blazing hot!

As everything, there are ifs and buts.

You leave all of the lockshields wide open and let the system self balance.
Your system is well designed and installed in the first place.
Nothing is broken,
etc.

You proved my point.
By "unbalancing" that which didn't need to be, it now works properly.
Within reason, it will now perform much better and heat the room as it should until the TRV kicks in and pushes the system HW somewhere else that needs its.