Hot water return in Hep2O? is this really a problem?

[Great_scot_selfbuild]

I've come across this statement:

“Hep2O should not be installed in Continuously operated re-circulating systems (Secondary Hot Water Circulation / Ring main installations).”

 

I was planning on using Hep2O pipework from the plant room to the end points, with the long hot water runs (20-30m) having a 10mm return line to enable circulation to avoid running taps, wasting water and waiting for the water to heat up.

 

I was sure I'd come across this approach by others - is this something I should be worried about? if not, why not?

[JohnMo]

Are you actually going to run continuously - I don't and wouldn't if I were either. Get a pump with a timer and thermostat and set a time or various time windows. The pump will run until the thermostat senses the return water at its set point pump then switched off. As the water cools the thermostat triggers the pump to start again.

[Great_scot_selfbuild]

55 minutes ago, JohnMo said:

Are you actually going to run continuously - I don't and wouldn't if I were either. Get a pump with a timer and thermostat and set a time or various time windows. The pump will run until the thermostat senses the return water at its set point pump then switched off. As the water cools the thermostat triggers the pump to start again.

I knew I was missing something!! @JohnMo Thank you so much for this. Just the advice / nudge I was needing 🤩 👏

[Nickfromwales]

31 minutes ago, Great_scot_selfbuild said:

I knew I was missing something!! @JohnMo Thank you so much for this. Just the advice / nudge I was needing 🤩 👏

You need to do the run in 15mm if you don’t want huge swings in the temp of the pipe.
 

You open the tap on such a long, timed loop, then you get tepid / warm / hot / warm / tepid / warm / hot / tepid / fully hot water (eventually).

 

If it’s for a basin for eg then you’ll be surprised at how hot you need this (entire) loop to (consistently) be to have an effective setup. For a bath or shower feed you’d just open the hot tap full bore and not give 2 fecks what temps you get before you get delivery of the water from the cylinder at that temp. 

[torre]

8 hours ago, Great_scot_selfbuild said:

Hep2O should not be installed in Continuously operated re-circulating systems

I'm a fan of Hep2O but that advice is direct from the manufacturer, so probably best heeded, Presumably doesn't like to be hot/expanded for too long

[-rick-]

2 hours ago, JohnMo said:

Get a pump with a timer and thermostat and set a time or various time windows. The pump will run until the thermostat senses the return water at its set point pump then switched off. As the water cools the thermostat triggers the pump to start again.

 

44 minutes ago, Nickfromwales said:

You open the tap on such a long, timed loop, then you get tepid / warm / hot / warm / tepid / warm / hot / tepid / fully hot water (eventually).

 

I thought the way to do this on a new install is to have sensors in the rooms with taps to switch the pump on (with heat based shutoff) when the rooms are occupied/light is on? Doesn't this avoid problems here?