Motorised valve for gravity HW ?

[dal5band]

Friend of ours has gravity HW with no control except the boiler temperature. The pump runs the CH and we have just installed a thermostat to control the pump. The next step would involve plumbing.

Would a motorised valve in the gravity circuit still give enough flow or should they go fully pumped with two valves ? HW circuit is 28mm pipe. Access is good in the boiler cupboard (floor mounted boiler) with both circuits coming direct from the boiler.

 

[Hugh Jaleak]

Honeywell 'C' plan covers pumped CH/Gravity HW systems. http://www.honeywelluk.com/products/Systems/Wired-Sundial/Sundial-C-Plan/

For critical safety reasons it is vital the motorised valve MUST be fitted in the return from the cylinder.

 

[Tipper]

I've done both before, ie, just a control valve on the return to the boiler, and later added a pump near the valve to improve the hot water recovery time. Both worked well.

 

[Galoka]

Yup, certainly add the valve, certainly consider having it pumped as well (existing pump, or additional pump depending on setup).

I've recently converted our old gravity HW system to pumped and the cyclinder recovery time is much quicker, unsurprisingly - esp. as we had a rather convoluted pipe route

 

[dal5band]

Cheers - I'll let him know the options.