Radiator Sludge

[JohnD]

That radiator clearly has poor circulation. It might not be caused by sludge. What happens if you turn off all the hot ones?

When you balance your radiators, almost all the adjustment is within the first turn from fully closed. Half a turn open is a good starting point.

If any of your radiators is wide open, it will steal flow from more distant ones.

 

[denso13]

View attachment 404614


Old rectangular style. Above is thermal photo I took last night. I’ll post normal pic when back at home.

Isolate is not meant in any detailed / technical sense, meant more that one radiator is with “fully open TRV” and the rest are off and checked to be so. I also tried turning lock shield on that specific radiator a few 1/2 turns, and it made no difference. I restored to original position afterwards.

Is that a connection to the top on the right hand side? If so, it looks like it could be the return, which is wrong.

 

[RainTown]

Is that a connection to the top on the right hand side? If so, it looks like it could be the return, which is wrong.

Lock shield is bottom left. TRV is top right. That’s been same for 20 years.

 

[RainTown]

That radiator clearly has poor circulation. It might not be caused by sludge. What happens if you turn off all the hot ones?

When you balance your radiators, almost all the adjustment is within the first turn from fully closed. Half a turn open is a good starting point.

If any of your radiators is wide open, it will steal flow from more distant ones.

That thermal foto was taken when TRV on one radiator, that one, was the only one open. Every other radiator was stone cold.

 

[denso13]

Lock shield is bottom left. TRV is top right.

Still looks wrong, which won't be helping things.

 

[RainTown]

Still looks wrong, which won't be helping things.

Can you be more specific on what you mean by “wrong”. All, or almost all, are connected the same way ?

 

[denso13]

Can you be more specific on what you mean by “wrong”.

The flow should be to the top, it doesn't look like that in your photo.

 

[RainTown]

That’s the actual radiator.

Most (4 in total) of the others are the same, lock shield bottom left , TRV top right.

One has it diagonally swapped, lock shield bottom right , TRV top left. That’s the one in kitchen, physically closes to boiler, also doesn’t work good at all

One has both at bottom, lock shield left, TRV right. That’s the radiator that works best.

This was all setup when central heating system was setup approx 20-25 years ago, which included installing all the piping to all the radiators.

Sorry if I appear slow/stupid, but I’m not understanding “looks wrong”? Over those 20-odd years lots of people would have looked at the system, annual services, little issues, ... Eg semi-recent Baxi boiler installation. They didn’t mention anything was wrong with how radiators were connected, in this sense ? As I wrote, they removed all the radiators and emptied them into a drain outside. And reconnected same way as before, at least I presume so.

 

[denso13]

Most (4 in total) of the others are the same, lock shield bottom left , TRV top right.

The valves don't matter. Again, it just looks like it is piped flow to the bottom, which might not rule out sludge, but it is still wrong.

 

[endecotp]

View attachment 404614


Old rectangular style. Above is thermal photo I took last night. I’ll post normal pic when back at home.

Slightly unusual to have one connection at the top, it’s more common to have both connections at the bottom.

I agree with @denso13, the circulation is probably the wrong way. Hot water is entering at the bottom left, rising straight to the top, crossing to the right and exiting. I guess you can feel this if you touch the pipes.

If all the radiators are the same, I guess that the flow and return got swapped at the boiler by one of your “plumbers”.

Note that when rads are plumbed from the bottom, swapping flow and return may not matter. Some TRVs are bi-directional, others have a preferred direction marked with an arrow. With a top connection, it needs to be correct.

 

[dilalio]

TBOE

 

[RainTown]

Ok, so if I am understanding correctly, there’s now a new theory, it’s just setup wrong?

The old boiler certainly worked the radiators better, but as I didn’t live there I can’t really quantify this claim. And it was years ago. The boiler was relocated when the Baxi was installed, about 60cm left, but it would be a bit of a leap to say the Baxi installers swapped flow/return, would it not?

And the fact that the radiator with both connections at the bottom is working best is also a bit suggestive!?

The TRVs are Hive TRVs. They were installed by same guys who did the Baxi installation. I use them mostly in manual mode. The new TRVs are in same places as ones they replaced.

Here’s the living room radiator , the biggest, plus 3x thermal fotos taken 5/10/15 minutes after I turned it on.

 

[Harry Bloomfield]

Sorry if I appear slow/stupid, but I’m not understanding “looks wrong”? Over those 20-odd years lots of people would have looked at the system, annual services, little issues, ... Eg semi-recent Baxi boiler installation. They didn’t mention anything was wrong with how radiators were connected, in this sense ? As I wrote, they removed all the radiators and emptied them into a drain outside. And reconnected same way as before, at least I presume so.

I would suggest, that your best way forward, is to study how central heating systems work, then you will be better armed to understand what is said on this forum - they are not particularly complex, to understand just the basics. With just a bit of understanding, you will be able to tell us the type of install you have, and get better, more accurate advice.

Basic things, like checking whether the flow and returns of the system have been mixed up, and whether you have an open vented system or not.

Your thermal photos above, seem to show that at least that rad is clear of any sediment. It takes a little time, for all the cold water in a radiator, to be pushed out, and replaced by the hot.

 

[denso13]

And the fact that the radiator with both connections at the bottom is working best is also a bit suggestive!?

TBOE connections (what you have) are actually ok, in fact they give a better heat output/efficiency.

Ok, so if I am understanding correctly, there’s now a new theory, it’s just setup wrong?

Maybe not, just pointing out that this won't be helping.

 

[endecotp]

it would be a bit of a leap to say the Baxi installers swapped flow/return, would it not?

They quickly remove the old boiler and dump it in the garden. Now they’ve got a load of pipes sticking out of the floor and a boiler with some connections. They can probably identify the gas pipe, I hope. The others - well, some are 15mm and some are 22mm. They connect the 22mm pipes to the CH flow and return, and turn it on. Great, the radiators don’t fill with gas! And they get warm (kinda). Job done, go to pub!

Very easy to get it wrong, I would say.

View attachment 404646

It seems like it may have a baffle (diverter) 3/4 of the way along.