Balancing rads help.....

[marshian]

2 hours ago, Dee said:

I've read that TRVs shoukd be removed completely when balancing, is this relevant?

 

Fully open is fine unless the rooms are at 30 deg C they shouldn't intervene

 

Removed just makes 100% sure they don't interfere

[marshian]

3 hours ago, Dee said:

You're going to hate me but.....everything was going fine until Yesterday when i turned the TRVs off in the 5 rooms that I want to close off for the winter. Last night all was well with the remaing 9 rads but When heating came on today the two troublesome rads were stone cold again.

I'm turning the 5 Trvs back on one by one and the 2 rads are slowly heating up albeit not to the level before.....sorry

 

A thought................

 

How old is the house - has it been knocked about or extended?

 

I just wonder if part of the circuit has been piped up single pipe configuration (AKA the old way where the rads are daisy chained return from one rad going to flow of another and so on)

 

Nah it couldn't be that surely

 

Then again I look back at some of the temp logging and Kitchen 1 and Kitchen 2 and think ooh the return from 1 rad is the flow temp for the other................

 

Originally one rad and then another one added without taking the feed from flow and piping up a separate return

[marshian]

4 hours ago, Dee said:

Yes

 

OK a constant flow temp at least means you can see differences in the flow and returns

 

4 hours ago, Dee said:

Yes

 

Good You don't want TRV's influencing the flows

 

4 hours ago, Dee said:

No, when fully warmed up

 

Ahhh - IMO Not the best time to balance - I know you have all the TRV's open but the rads will have already started to have hotter returns due to warmer room not sucking the heat out of the rads so your delta will be smaller

 

You really want to do it 30 mins after a cold start - enough time to get flows thro all the rads but not enough time that the rooms are warm and are already not pulling the heat from the rads due to a smaller differential between room temp and mean rad temp

 

4 hours ago, Dee said:

Yes

 

Good you don't want the TRV's to start messing with the flows

 

4 hours ago, Dee said:

Conventional wisdom on many websites state this as being the most efficient 

 

With "single panel single convector" T11 rads sized for an 80 deg flow temp it might be conventional wisdom but we really shouldn't be running condensing boilers like that..............

 

At 55 flow temps best I could get

 

on T11 Rads was 7 to 8 deg

On T22 Rads (Double panel double convector) was 12 to 14

 

Boiler flow temp 55

Boiler Return temp 39 (so overall delta across the boiler was 16 deg)

 

And to do that I had to really slow the flow thro the rads to a point where I needed flow thro the ABV as soon as TRV's started intervening

 

System was much happier with a bit more flow thro the rads lower differences between flow and return on each rad but no ABV until circuit got down to less than 5 rads and very similar delta at the boiler

 

It was at this point I realised trying to achieve conventional wisdom on rad deltas was bloody stupid.....

[Dee]

Well, the system is 22 yrs old. We extended it about 18yrs ago but havnt added or changed the heating configuration since. I did add a bathroom last yer but it has a column rad. 

Once I had turned all the 5 rads back on tonight the two heated right back up.

I think you could be right about the kitchen!!

[marshian]

1 minute ago, Dee said:

Well, the system is 22 yrs old. We extended it about 18yrs ago but havnt added or changed the heating configuration since. I did add a bathroom last yer but it has a column rad. 

Once I had turned all the 5 rads back on tonight the two heated right back up.

I think you could be right about the kitchen!!

 

If I am right about the kitchen then whichever rad is warmest the lockshield on that rad needs to be wide open - balance the circuit on the lockshield on the other rad.

 

You will still get a drop in temps across each rad but there will always be one rad that has the higher temps

 

If I'm wrong and it is plumbed in normally - ie two pipe than a bunch of your other rads will go cold quickly and your return temp at the boiler will go up