Reverse Circulation? (threads merged)

[blackbirdxx]

Surely, the set up is correct then? The towel rail shouldn't be connected after the HW valve as it would then only heat when the HW is being called for? I'm obviously missing something here? This makes the current set up (above pics) correct, doesn't it?

 

[blackbirdxx]

Added a couple more pics to show pipes which perhaps are obscured as I may be confusing people. As discussed earlier, this towel rail is designed to continue operating when the CH is turned off during summer months to keep towels warm. You can see from the earlier pics where the return from this heated towel rail connects to the outlet from the cylinder coil by a syphon which comes out of the floor and back down again. I'm not sure why the plumber has done this inverted U arrangement, is there a reason?

thanks.

 

[ianmcd]

heated towel rail connects to the outlet from the cylinder coil by a syphon

What Syphon ?

 

[ianmcd]

Surely, the set up is correct then? The towel rail shouldn't be connected after the HW valve as it would then only heat when the HW is being called

It will only heat when the HW or CH are switched on, the towel rail cant tell the boiler and pump to come on

 

[blackbirdxx]

It will only heat when the HW or CH are switched on, the towel rail cant tell the boiler and pump to come on

So the towel rail comes on when the HW or CH is switched on with the current arrangement. Surely the system is plumbed correctly then?

My syphon question query refers to the inverted U pipework which forms the return pipework from the heated rad. Rather than connecting this rad return to the return pipe from the rest of the rads, the plumber has directed the pipework about 400mm above the floor boards to go down again and connect to the cylinder coil exit pipe. All this can be seen in the earlier pics. - not sure why he has done this?

Apologies for labouring all of this, but thanks for your patience...

 

[blackbirdxx]

This pic best shows the inverted U pipework from the heated towel rail..

 

[fixitflav]

Should there be a minimum length of return pipe between the cylinder return T and the radiator return T to prevent reverse circulation?

No. Provided the HW cylinder return comes in after all the rad returns are commoned, the distance doesn't matter.

 

[ianmcd]

I still cant see an inverted U pipe can you point out what you are talking about, is this what you are referring to ?

 

[blackbirdxx]

Sorry for the confusion....
The inverted U-pipe I'm talking about is the 15mm pipe coming out of the carpet (left of the pic) by about 400mm, goes over the Honeywell CH valve and then goes down again to connect to the outlet pipe from the cylinder coil. It's got the cable to the cylinder thermostat tied to it on the top. This pipe is the return from this heated towel rail but I'm not sure why the plumber has done this arrangement rather than connecting to the radiators return pipe beneath the floor boards.

This thread is about reverse circulation with my upstairs rads getting hot when CH is off/HW on and I'm wondering whether this heated rail pipework has anything to do with the problem I'm having?

many thanks for your help...

 

[denso13]

I'm wondering whether this heated rail pipework has anything to do with the problem I'm having?

Looks like it, the return should go to the heating return, not the coil return.

 

[denso13]

Turn the towel rail off and see if the rads still heat up.