determine flow direction in drained-down system at boiler?

[David Robinson]

Having googled this, I realise I should have figured out the flow and return of each rad before taking the system to pieces. Hindsight etc!

Unfortunately, the system is completely drained down, and all the old rads have been removed. So checking which side of each rad gets hot first could be a challenge!

However, access to almost all pipes under-floor is currently good, so I could "easily" do some tracing.

In a drained-down system, how can I tell, at the boiler, which is flow and which is return?

TIA

Cheers, David.

[Tim Downie]

Any arrows on the pump? The boiler may also have indications of which terminals are flow & return. If not, you can almost certainly google for a boiler manual which would show which was which.

Tim

[John Rumm]

What sort of boiler, and where is the pump? What type of system - i.e. combi, Y plan etc?

[spamlet]

Why do you need to know: you'll soon find out when you put the rads back and turn them on?

S

[Tim Downie]

And then find that you've fitted the TRVs the wrong way round? No thanks.

Tim

[Frank Erskine]

ITYF that most TRVs nowadays don't care about direction of flow. Certainly my Danfoss ones fitted six or seven years ago are bi-directional.

[spamlet]

IMHO: TRVs belong in the recycling bin where they will do the most for the environment, and save an awful lot of time faffing about unsticking them all the time.

S