Outdoor water pipe

[Sunshine12]

Planning a hot & cold tap down the garden approx 20m away from house. For washing hands, next to BBQ, kids toys, dog etc. Really want the hot so please don’t put me off!

Currently have 50mm dia flexi ducting in the ground (contains armoured cable) if that is of any use.

Should I run barrier pipe? Presume mdpe is just for cold? Will it need lag/insulating too, if so any suggestions please?

 

[oldbuffer]

1. I assume you don't mean to run the pipes with the armoured cable. Not on.
2. You need a drain off point at the lowest point of each run.
3. Doesn't really need barrier pipe as not closed circuit.
4. You could run hot and cold together (hot above cold), both suitably insulated, Armaflex. Perhaps in soil pipe or 50mm waste pipe? I'd use Hep2O or JG Speedfit for the pipe.
5. Despite insulation both will freeze in winter, hence the need to drain.
6. Connections inside thermal envelope of property need (for both hot and cold):
6a. Non-return valves. (Not on hot if tank fed).
6b. Isolation valves.
6c. Drain off points.
7. I'd suggest a Thermostatic Mixing Valve near the hot outlet. Frost protected and drainable. Otherwise there is a risk of scalding. 20M run really too much to have TMV inside which would have been better. Others may have a different opinion.

 

[Hugh Jaleak]

I would also be concerned about drainage. 20m is a long dead leg, you'll need to run a fair drop off from the hot to get hot water to the tap, where will this wasted water go?

 

[Sunshine12]

Thanks - the garden has a very slight slope down away from house then level to the tap location. Tap will be used mostly Spring/Summer.

Sorry, meant I have spare 50mm ducting that I could dig, bury and house the water pipes in?

Ok to use standard white PEX pipe then?

What is the longest run for a TMV?

Newly fitted pressurised system (system boiler & 300L tank) - so would a non-return valve be needed?

Will definitely use isolation valves

drain off points - sorry not entirely sure on this could you please elaborate

garden is currently being dug up for a new patio so I’m planning to lay these pipes now

 

[Sunshine12]

It’s for occasional use eg sink next to the BBQ for washing hands, for topping up the kids paddling pool instead of using kettles, rinsing the dog rather than freezing him

 

[oldbuffer]

1. The 50 mm ducting should be fine. If 15 mm pipe, use Armaflex AF-CO-13X015. Pipe + insulation = 15 + 1 + (2 x 13) = 42 mm.
2. Standard PEX would be OK.
3. Don't know longest run for TMV, but they are supposed to be installed close to the outlet. Don't know how you could set one up and adjust it with a 20M run for the hot to arrive at the outlet after the TMV. Perhaps check with Pegler?
4. You'd need non-return (double check, e.g. Screwfix 96336) valves on both hot and cold.
5. Make sure you use full bore isolation valves on a run this long.
6. A drain off point is a place where you can drain the water from a section of pipe work, once the source of water into that section has been isolated. If (unlikely) the taps are the lowest point, you can drain through them, otherwise use something like Screwfix 99939 inserted into a tee at the lowest point of each run. The water regulations state there should be an internal drain off as well.