Radiators: Sides for Flow and Return?

paperclap

Hi all,

I’ll soon be replacing our central heating system. New, higher pipes and new radiators.

Our current system has the flow pipe running into the right side of the rads, and of course return pipe out the left side. When I replace it all, is there any use in fitting the flow into the left side of the new rads, and flow out the right? Maybe it doesn’t matter, but I could have sworn I’ve read somewhere that it is best practice to fit the flow pipe into the left side, for whatever reason.

Our conservatory rad (which I am not replacing), is a bit odd, I think. Or, maybe it’s not. The flow pipe is on the left. Return on the right. But, odd thing is, the TRV is on the return pipe. I know TRVs are bidirectional these days, and maybe it doesn’t matter all that much… but is it not best practice to fit TRVs on the flow pipe into the rad? If so, is it worth dismantling the TRV and other valve and swapping them around?

Thanks!

Grenage

I wouldn't dream of moving the pipework or valves without good reason.  Either way is fine, it's just a chunk of metal with a chamber running through.

It's a bit more efficient to have the trv on the feed, but it's not going to make much difference.

paperclap

Grenage said:

I wouldn't dream of moving the pipework or valves without good reason.

Do you mean the rads too?

Our current pipework is so low to the ground we can’t have any decently sized skirting board down.

Our current rads are type 11, so looking to change for type 21 rads.

jefaz07

Grenage said:

I wouldn't dream of moving the pipework or valves without good reason.  Either way is fine, it's just a chunk of metal with a chamber running through.

It's a bit more efficient to have the trv on the feed, but it's not going to make much difference.

Either way is fine providing you have bi directional valves. 

Most are these days but just something to be mindful of. 

Bendy_House

Just as you say, LWM - the rad can be connected up either side. An exception to this are some column and 'designer' rads which should only be connected one way, but this will be marked clearly with labels.

For normal panel rads such as yours, the rad itself is symmetrical.

Yes, most modern TRVs are 'bi', but I would still always fit them on the flow side. The traditional reason for this is that the rubber washer which does the 'closing' will have the water flow acting to keep it open - pushing up against it trying to shut down - and it was up to the TRV head to do the work against this flow. If an oldie was connected the wrong way around, the flow would actually push the rubber seal prematurely shut when it was getting close to this point, and it would also struggle to open again as the TRV head tried to tell it to, since the water flow was trying to keep it shut; the valve wouldn't then give delicate heating control. They've obviously overcome that issue with the bi models, but I'd still fit it on 'flow' tobesure tobesure. It's also just 'nice' to know which end is flow...

A wee tip - mount the rad without the bleed screw in place. Once mounted on the wall, place your spirit level on the rad and see if it's slightly less than perfectly horizontal. Whichever end is fractionally higher, fit the bleed screw to that end.

Grenage

laurencewhymark said:

Grenage said:

I wouldn't dream of moving the pipework or valves without good reason.

Do you mean the rads too?

Our current pipework is so low to the ground we can’t have any decently sized skirting board down.

Our current rads are type 11, so looking to change for type 21 rads.

I'd move then around if they were in the way, for sure; I just wouldn't move it just to switch the feed or valve orientation.

NSG666

As others have said it doesn't matter. As your pipes drop down from above, personally I'd just run them so they don't cross over each other e.g. where pipes drop down to left of radiator: the left hand pipe becomes the bottom pipe and goes to the RHS of the rad and the RH pipe becomes the top pipe and goes to the LHS of the rad.

TRV position - put it where easiest to access it and if the rad is in a corner of the room it's best to put the TRV on the opposite side to the corner so it's reacting to the main room temp rather that the temp in the corner. It is possible to fit TRVs with the head horizontal (and is often the way in commercial buildings) but I think they look a bit odd and are more likely to get damaged.

NSG666

Bendy_House said:

Just as you say, LWM - the rad can be connected up either side. An exception to this are some column and 'designer' rads which should only be connected one way, but this will be marked clearly with labels.

Unfortunately some only have the tiniest of stickers which can fall off and no mention of direction in the instructions and/or the existing rad has already been removed so you don't know which if the flow and return anyway. Bad enough if it's a double rad that can be spun 180deg but a PITA on the singles and they are all swines to drain. I don't miss the job!