Anti Scald Valve for Vented System

youtheman

Folks, I'm need some urgent advice. I have a plumber fitting a 300 litre twin coil vented cylinder. Initially I'll just hook up one coil to the central heating boiler. The second coil will be hooked up later to a solar panel.

I need to fit an 'anti-scald' (thermostatic) valve on the hot water outlet, especially if the solar system is being used. But I cannot get a valve for a vented (low pressure) system.

Can anyone point me in the right direction ? (I would try the supplier of the cylinder, but I've already had a falling out with them regarding the lack of information available on the cylinder).

Any guidance would be greatly appreciated.

youtheman

Panic Over.

After several phone calls I managed to speak to a solar vendor. He said that a standard thermostatic valve would work, but I should go up a size to reduce the pressure drop. He also advised fitting an NRV on the cold supply.

So that's the 'plan'. And hopefully no-one is going to contradict him (or I'm rightly screwed).

Cheers.

ccsolar

Hi Youtheman

Scald protection devices are a must in homes with young children, the elderly and physically challenged individuals - but are recommended for every home and may even be code in some areas. While caution is always first and foremost with regards to scald prevention, scald protection devices can help to maintain safer water temperatures.
Whole House Anti-scald Thermostatic Mixing Valve
Aquamix Valve by SparcoThese units are to be installed in a hot water line and require a cold-water feed. They also requires a NRV on the cold water feed line to prevent hot water from entering the cold water system. We also recommend a hot water expansion tank when you install these types pf valves to prevent excessive pressure on the hot water side (due to hot water expansion). These types are best installed right at your water heater.

CC

youtheman

Update.

The plumber installed the anti scald valve today (see photo). There is no non-return valve fitted on the cold side (I presume) as there is a dedicated cold supply from the header tank in the attic.

But I'm a bit concerned the way it is plumbed. The cold/hot water mixture feeds two supplies, the shower pump (facing down, yet to be fitted, where the closed valve is) and the remainder of the house (the valve pointing backwards, and then down). But if you follow the other hot water pipe out of the top of the cylinder (the one with the bend) you'll note that it can go up to the expansion tank in the attic, but also down, completely bypassing the thermostatic valve where it joins the supply to the rest of the house.

Does this look o.k. ?

youtheman

youtheman wrote: »

Update.
completely bypassing the thermostatic valve where it joins the supply to the rest of the house.

Yep, your right the water will take the path of least Resistance bypassing the valve when it tries to reduce the the hot, the cylinder needs the open vent but you could remove the length feeding back into the hot water supply, Gary.

youtheman

Thanks Gary. Pays to be on the ball.