Trickling cold water and no access to CWSC

[moorer]

Hi all, this is my first post.
I've replaced a bath/shower mixer for a friend who lives on the ground floor in a 1930's maisonette. I had to drain down the cold water cistern to do it as the woman who occasionally lives upstairs is a bit strange and after a number of disputes won't let him have access to the roof space where the tanks are.
I tested all the taps after I fitted the new one but didn't run the water long enough - he rang me this morning to say that his cold water trickles to nothing after about 20 seconds running.
Would I be right in thinking I have either a blockage in the tank from having drained it down or an airlock?
If so, can I tackle anything from the ground floor or do I have to find a way for my friend to track this woman down to get access.
I've seen an earlier post about big thumbs on the kitchen tap for an airlock - is this the solution and is there a contraption I can use as my thumbs are very small!!
Many thanks

 

[traineedrip]

you might be able to pull the air lock through with a wet vac.

not 100% sure but id be suprised if the upstairs neighbour can prevent access to the mans cwsc. be fun if the float valve fails lol

 

[justlead1]

Hi Turn cold only on and blow it back with hose on main, say15 seconds, then let cold run. This should clear it. Good Luck

 

[NickH]

Ive had real trouble in the past with an old tank that had stopcocks on the outlets. After refilling the tank the water simply would not flow through the stopcacks fast enough to clear the air out of the pipes. Eventually had to run a hose pipe up from the outside tap and poke it down each outlet to clear the airlock, major major a**e ache.

 

[Winston]

And if you are going to you a hose not a job to be done on your own, caution.

 

[moorer]

Thanks guys.
I've ordered a couple of hose connectors to fit on taps and I'm going to try the hose pipe/ mains pressure option first, and if all else fails it's trying to get access to the loft. I've told my friend he really needs to think about getting an unvented heating system and direct cold water if the woman upstairs carries on being such a pain as anything involving water that's got moving parts that you can't get at is not a good idea.
Funnily enough she had a plumber there last week who drilled through the external wall to fit an external drain cock on the front of the house to drain down her CH system....
I'll let you know if I manage to clear it and thanks again.

 

[moorer]

Thanks to all - it worked a treat.