Reverse Circulation

[fixitflav]

Only a short length of pipe is required to connect to the boiler return once the cylinder is removed.

To a point after all the rads returns are commoned? Are you sure?

 

[blackbirdxx]

So the plumber said. Wish I could attach a short video to this email which he did and is on Cloud but don't know how to do it. Basically involves uploading a link I think..

 

[ianmcd]

upload it to youtube then post the link on here

 

[blackbirdxx]

 

[ianmcd]

cylinder doesnt need to come out

 

[blackbirdxx]

Hi Ian,
Can you elaborate? Are you saying the pipe beneath the cylinder can be connected correctly to the boiler return without cylinder removal and not using a non return valve?

 

[ianmcd]

A non return valve will cause more problems than answers, The HW return is above the floor, so why would you remove the cylinder, is that bathroom radiator a new addition?

 

[blackbirdxx]

is that bathroom radiator a new addition?

Bathroom rad is on a summer circuit as was the rad which was removed from that bathroom. All pipework is new.

 

[ianmcd]

where is the return for that rad teed into ?

 

[blackbirdxx]

where is the return for that rad teed into ?

The return from the bathroom rad is the flexi one you can see next to the screwdriver in the below pic. It rises vertically in 15mm pipe by the door jamb, through the floor and rises about 500mm, cranks out and goes over the CH valve where it goes vertically downwards, picking up the outlet from the cylinder coil, goes beneath the floor boards where it turns through 90'degrees and connects to the main radiator return pipe (RHS 22mm pipe where boards have been removed).
Hope that makes sense....

 

[ianmcd]

close one of the valves on the bathroom rad and see if the reverse circulation stops

 

[blackbirdxx]

That was tried a while back and it doesn't stop the reverse circ.

 

[fixitflav]

Bathroom rad is on a summer circuit

What do you mean by a summer circuit? If that rad is fed from the HW valve (in parallel with the HW cylinder) the return should be commoned with the cylinder return, before teeing into the main rads return (at the appropriate place!).

Perhaps it's just me, but I can't tell exactly what does what from your video and pic. It might be a good idea to draw a flow diagram of the system. From that you can see why the rads get flow when HW calling, if returns wrongly connected.

 

[blackbirdxx]

What do you mean by a summer circuit?

I understood a summer circuit is where the bathroom rad is plumbed to the HW circuit for warm towels in the summer when the CH is off.

Probably best if I don't draw a flow diagram as I'm not confident mine will be accurate as I'm not a plumber or CH fitter and I can't accurately see what's going on under the cylinder. There are a lot of connections under the cylinder which is why I'm guessing is why the second plumber is saying it must be removed to do the repair.

All that said, your description of how a 'summer circuit' should be plumbed looks to me the way it is actually plumbed ie. the radiator return is connected to the cylinder return, before teeing into the main rads return. That would mean that the original plumber got it correct, yes? My belief from what I read is that the cylinder coil outlet should be the last T on the return to the boiler...

 

[fixitflav]

All that said, your description of how a 'summer circuit' should be plumbed looks to me the way it is actually plumbed ie. the radiator return is connected to the cylinder return, before teeing into the main rads return. That would mean that the original plumber got it correct, yes?

As far as the HW cylinder and bathroom rad are concerned, yes.

My belief from what I read is that the cylinder coil outlet should be the last T on the return to the boiler...

That's correct, but it probably isn't plumbed like that, or you wouldn't have your problem. That's what needs altering. Whether the HW cylinder has to come out to do it I can't tell from here.