Does a radiator like this make sense?

ThisIsWeird

pieroabcd said:

I took only  partial  measurements for lack of time, but it's been quite revolutionary so far.



Before the test: all flow valves were mostly closed, except at the second floor where flows and returns were fully open. The return valves without TRV were closedi in large part, fully open at the second floor. The TRV were set at 3. Blown my mind.
Now: all flow valves are fully open (except the T21 in the study that is back at 3 because it was too hot). So why don't you tweak down the l/s on that one? The return  valves without TRV (taps) at the ground floor are mostly closed, 1/4 of turn only. The TRVs are set at 3. When are they set at '3'? During your balancing? Or now?
The water temperature was the usual 60 degrees.
The temperature differences are not really satisfying, but I've stopped measuring them because after 30 minutes all radiators were HOT, even at the second floor. The only problem there is the cold bottom part of the radiator. Maybe sludge. Which radiator?
I've finally seen the TRV make a real difference. In the past they didn't, maybe because the flows were almost closed (opened only by 1/4 turn or so)? It's also fast: 5 minutes after turning down the TRV the rad temperature had adjusted. Cool.
The delay between the radiators coming up to temp is much lower than before. Probably becuase they are ALL being supplied now, for the first time?! Now the columns ones at the ground floor heat up more or less at the same time and at the same temperature. Cool! The fastest of course is huge T22 in the kitchen. Why - becuase it's closest to the boiler? If it's heating up notably faster than the rest, then its l/s needs a further tweak.
The T22s at the 1st floor got very hot too, as fast as the others. In the past due to my previous meddling they got lot less hot, especially the one in the second bedroom that is slightly smaller.
Can I leave the flows fully open as they are now or could they create problems? Why would you leave them open? Why not set them to the temp required by their respective rooms? The returns would stay as they are of course. By 'returns' you mean the now-set l/s's?
Maybe I could even lower the temperature to 55°. You could try, and it might be fine for this mild spell. But, come winter...
The TRVs have no arrows. I hope that means they are 'bi'. Photo?

Bits in bold.

Nice job! It sounds as tho' you have largely sorted this :-) It's a rough science, and the figures don't need to be anywhere near spot on. As long as all the rads heat up at roughly the same rate, and all rads do become hot after, say, a half hour, you've pretty much nailed it. Bear in mind that, in practice, some rads are bound to be off, or will become so when their TRVs shut them off, so the rads you really want the hottest will likely be faster at doing their job.

Which rad has a cold bottom? A column type?

pieroabcd

ThisIsWeird said:

pieroabcd said:

I took only  partial  measurements for lack of time, but it's been quite revolutionary so far.



Now: all flow valves are fully open (except the T21 in the study that is back at 3 because it was too hot). So why don't you tweak down the l/s on that one?

I can't find the hexagonal key 

 The return  valves without TRV (taps) at the ground floor are mostly closed, 1/4 of turn only. The TRVs are set at 3. When are they set at '3'? During your balancing? Or now?


Now, after this balancing 

The only problem there is the cold bottom part of the radiator. Maybe sludge. Which radiator?

The column radiator at the second floor in the bedroom 


The delay between the radiators coming up to temp is much lower than before. Probably becuase they are ALL being supplied now, for the first time?!

Indeed 


 The fastest of course is huge T22 in the kitchen. Why - becuase it's closest to the boiler? If it's heating up notably faster than the rest, then its l/s needs a further tweak.


Yes, near the boiler, with the TRV on the return pipe. 


Can I leave the flows fully open as they are now or could they create problems? Why would you leave them open? Why not set them to the temp required by their respective rooms?

Remember that on many radiators I have the lockshield on the flow pipe 
 (fully open) so the temperature can be set only on the TRV that sits on the return valves.
On 4 radiators I have only taps.
I have an old style hearing system. 


The returns would stay as they are of course. By 'returns' you mean the now-set l/s's?


By return I mean the pipe that return cooler water to the boiler, that in most cases on my rads have a TRV. The blue arrows in my floorplan

Bits in bold.

Nice job! It sounds as tho' you have largely sorted this :-) It's a rough science, and the figures don't need to be anywhere near spot on. As long as all the rads heat up at roughly the same rate, and all rads do become hot after, say, a half hour, you've pretty much nailed it. Bear in mind that, in practice, some rads are bound to be off, or will become so when their TRVs shut them off, so the rads you really want the hottest will likely be faster at doing their job.

Which rad has a cold bottom? A column type?

Thanks.
Yes, the column rad at the second floor in the loft. 

I've replied inline above, in italic. 


For clarity in the picture I've added a red arrow indicating hit water from the boiler and a blue arrow for the colder water flow. 
It also shows where I have a TRV and where there's a tap or a lockshield. 

ThisIsWeird

pieroabcd said:

Yes, the column rad at the second floor in the loft.

If it's a column rad, there could be other reasons why is has a cold butt, such as it being connected the wrong way around. These column rads have rubber bungs in the bottom tube, that forces water to go up one set of tubes, and back down t'other. Not sure why they are directional, but mine were, so expect them to not be 100% if the wrong way around. I wouldn't suspect sludge in only one rad.

Remind me - you did test the water, and it was clear? Do you have a Mag Filter fitted?

Pic of a typical TRV? With no arrow, I'd assume it was bi. Regardless, you don't make the TRV a lockshield and vice versa! You fully open the TRV, and tweak down the l/s to get the right heat-up speed. Then you leave the l/s alone, and use the TRV for heat output control.

The fastest of course is huge T22 in the kitchen. Why - because it's closest to the boiler? If it's heating up notably faster than the rest, then its l/s needs a further tweak.

Yes, near the boiler, with the TRV on the return pipe. Doesn't matter - tweak the l/s down a further fraction so it's no longer the 'fastest'.

Can I leave the flows fully open as they are now or could they create problems? Why would you leave them open? Why not set them to the temp required by their respective rooms?
Remember that on many radiators I have the lockshield on the flow pipe (fully open) so the temperature can be set only on the TRV that sits on the return valves. No it can't - the TRV is your control valve, regardless of which side it's on. The l/s sets the rad balance - regardless of which side it's on.

On 4 radiators I have only taps.

I have an old style hearing system. What's an old-style heating system?

The returns would stay as they are of course. By 'returns' you mean the now-set l/s's?
By return I mean the pipe that return cooler water to the boiler, that in most cases on my rads have a TRV. The blue arrows in my floorplan. Set the rad balance using the l/s, regardless of which side it's on.

pieroabcd

Yes, I had to close even more the lockshield on the radiator in the kitchen.

Can someone recommend some reliable bidirectional TRV?  I have 4 radiators to install it on.
Is it true that it's better if they are set horizontally rather than vertically on the water pipe?

FreeBear

pieroabcd said: Is it true that it's better if they are set horizontally rather than vertically on the water pipe?

As long as the arrows point in the direction of flow, it doesn't make much difference whether they are mounted horizontally or vertically. Mounted vertically on the inlet side is the most common.

ThisIsWeird

And vertically is neater. 

pieroabcd

Now that they are finally receiving enough water I've noticed that column rads are remaining hot significantly longer than the T22s when the boiler stops heating. 

FreeBear

pieroabcd said:

Now that they are finally receiving enough water I've noticed that column rads are remaining hot significantly longer than the T22s when the boiler stops heating. 

If the water volume is considerably larger, heat retention isn't surprising.

I've noticed that my room temperatures will continue to climb by 0.1-0.2°C after the boiler shuts down. All helps to keep the house warm.

pieroabcd

I thought that the material determined the heat retention. Aren't both the column radiators and the Flomasta t22 made of steel? Or maybe the fins between the panels are made of aluminium?

 I've also wondered why aluminium radiators cost 3x the steel ones: only for a matter of request? The material is definitely cheaper. 

FreeBear

Larger, heavier cast iron & steel radiators will store a fair bit of heat in the metal, but they also generally contain quite a bit more water - The fins on my Flomasta radiators are steel (helps to keep the cost down).

Aluminium conducts heat much more quickly that steel, so are often specified in low temperature systems. They often contain less water to allow the system to get up to working temperature faster. And being a more expensive metal is reflected in the price you pay for them.