Confused, can anyone shed some light?

[Liamsparks]

Hey, been to look at a job this evening its not your standard S, Y or Combi system. The plumbers gone in and only changed the boiler but disconnected all the cables to it.

Scenario:

Boiler, with pump above it, basic programmer (HW ON, CH ON)

Then in the airing cupboard theirs one 2port valve and the cylinder stat is a plumbed in one which goes to a stat'ed TRV (little copper wire) No electrics involved.

system does not have a Room stat but does have frost stat.

When speaking to the plumber he couldnt describe what system it was but said

When calling for water valve is closed
When calling for heating valve is open

The wires which are left dangling is:
Feed from FS
3 core (haven't yet investigated where from)
and a flex hanging down from the pump.


The bit which gets me is how can you call for HW when theirs no electronic stat involved? Can anyone work out how it was wired from the cables which are dangling? Nothing else seems to have been touched just those wires that are dangling.


After a busy day fitting PV panels this has got me stumped.

Thanks!

 

[no one likes us]

You have a very basic fully pumped system.When hot water is in demand it will start pump and boiler and go round coil in cylinder.If the tap stat on cylinder is happy with temp the boiler and pump will still run but go through by-pass on tap stat avoiding flow through coil.Its a very cheap and easy system to install with basic wiring.2 port only there to stop heating working in summer,bit like a non return valve.Normally there to work with room stat.
H/w in demand activates boiler and pump/
C/h in demand activates 2 port then boiler and pump
Hope this helps
Graeme

 

[Liamsparks]

Thanks alot for your reply. Only got boiler feed, pump feed and a 3 core where old wiring was presumably their will be more connections hidden somewhere.
Suppose it's just 3 core red and blue to mains and the yellow is switch wire that is the demand so connect boiler and pump live to that.