secondary circulation

[andyhass]

Hi all I'm after a bit of advice. I'm putting a downstairs toilet In a pretty big house and want to branch off the secondary circulation pipework to it. The bathroom hot tap will be the first draw of point from the cylinder although it's quite a run from it. I'm a bit confused as to how to do this without messing up the delivery of HW to the other taps around the house, please see attachment. I'm worried if I pipe in option 1 this will cause a short circuit and bypass the rest of the system, option 3 will work but will take forever to draw any hot water off if the pump isn't on so I'm swaying towards option 2 this is to restrict the flow back to the secondary circs forcing the flow round the rest of the circuit. Any thoughts on this or am I missing something? Thanks for your help

 

[bernardgreen]

you don't need to take flow and return to the new tap,

 

[andyhass]

Hi Bernard thanks for your reply. The problem with this is the tap is a good 8m from the HW pipe where I will make the connection so if I was just put a single feed to the HW tap without secondary circ to it it's going to take a while to draw any hot water off. It's only a toilet and basin so I want the HW there pretty much straight away.

 

[denso13]

Option 3 with the pump controlled by a pipe stat or timer. Make sure the loop is insulated well.

 

[bernardgreen]

Might cost more in piping and could delay hot water to the other taps.

I had the same problem in my cottage. Stone walls differing floor levels etc etc meant very long pipe runs between kitchen/utility and the bath room/toilet. The solution was two hot water cylinders.

 

[andyhass]

Thanks for your input guys really appreciate it. Option 4 is putting me off a bit for the sole reason I'll need to get 2*22mm pipes to it if I use option 1,2 or 3 I could get away with 15mm pipe. What are your thoughts on option 2? If I put a restriction on the return pipe to the main secondary circulation pipe back to the cylinder would this work? As well I was thinking if the pump wasn't on then the draw off wouldn't be as bad as as option 3.

 

[JimCrow]

Option 2 is the way to go with a lockshield valve just cracked open.

 

[Elkato531]

Why not just T off the loop and run to the new tap in 10mm plastic. With an internal diameter of 6mm, an 8 metre length will have a capacity of about 1/4 litre. Flow rate won't be great especially if its a vented cylinder but probably won't be an issue if only for a handwash basin.

 

[picasso]

I would go with option 3 with a pir sensor to control pump in the new toilet, if you go with the other options you will need balancing valves to control the flow in each branch.

 

[andyhass]

Cheers for all the advice much appreciated. I'm going to run option3 past the customer I was swaying towards option 2 but as picasso mentioned I might throw things out for the rest of the circuit. Top idea with the pir never thought of that

 

[Harry Bloomfield]

I would go with option 3 with a pir sensor to control pump in the new toilet, if you go with the other options you will need balancing valves to control the flow in each branch.

Rather than a pump, might a 2-port motorised valve work just as well, opened by a PIR or even the light switch if the light always needs to be turned on?

 

[dilalio]

Rather than a pump, might a 2-port motorised valve work just as well, opened by a PIR or even the light switch if the light always needs to be turned on?

No. Whole point with a recirc is to have DHW constantly circulating during demand periods for household bathing/showering etc... An additional PIR in the cloakroom overrides off times to start circulating delivery, ready for post-pee handwashing.