One isolating valve on both loft tanks inputs?

[phloaw]

Hi, just after the mains stopcock under my kitchen sink I have a tee, one pipe to drinkable water+washing machine and the other to the loft cisterns (talking about an open vented pumped S-plan system, standard here in UK).

I was wondering whether it is safe to add an isolating valve on the latter pipe, placing it right after the aforementioned tee (i.e., under the kitchen sink).

I am asking because I've read somewhere that the feed and expansion tank shouldn't have a valve on its input, but I couldn't find a consensus on that, online.

I am also suspicious because currently I have an isolating valve just before the bigger loft tank in the loft, not serving the FE tank. Which could be a hint that FE shouldn't have an input valve?

 

[Madrab]

Yes, an isolation on the mains feed to a cistern in the attic should always be fitted as best practice. At that point they are then classed as service valves and allow the separate supply to the cistern to be isolated and then worked upon, independent of the main cold supply within the house.

 

[phloaw]

Yes, an isolation on the mains feed to a cistern in the attic should always be fitted as best practice. At that point they are then classed as service valves and allow the separate supply to the cistern to be isolated and then worked upon, independent of the main cold supply within the house.

Ok, then I assume FE is not an exception to what you say. And that having the valve directly in the attic or beneath the kitchen sink doesn't matter.

Thanks!

 

[ianmcd]

Ok, then I assume FE is not an exception to what you say. And that having the valve directly in the attic or beneath the kitchen sink doesn't matter.

Thanks!

They are usually installed as close to the F&E as possible to allow maintenace without climbing in and out of the loft

 

[ianmcd]

If you think about it, say the service/isolating valve was in the kitchen,you then had to say change the ball crane assembly in the F&E, so you turn it off in the kitchen , go up change it, go back downand turn the water on and go back to check everything is ok and there is water poissing everywhere, so you have to get back to the kitchen to turn it off again, a valve right next to you and no dramas

 

[denso13]

I've read somewhere that the feed and expansion tank shouldn't have a valve on its input

There shouldn't be one on the outlet, but inlet is fine.