Cold water air lock

[steve0H]

Vented system.

I was installing a new sink at the weekend and had to drain our cold water storage tank and hot water cylinder to be able to work with the pipes as no service valves previously and gate valves from CWST have all seized.

When finished I turned mains back on and tanks refilled but our CWST fed taps (bathroom taps, bath, ensuite and downstairs cloakroom) cold supply only did not flow. Hot water working perfectly. I think it was likely an air lock so I got a wet vac and have sucked air out of all the affected cold water taps. This has worked to an extent but there is still poor flow, worse than previous to me working, and when I run the bath cold tap and try and run the basin cold tap, the basin cold stops (as does refilling of the toilet cistern) while the bath continues, albeit poorly. When I stop the bath cold, the basin will start working again.

I've tried repeating the wet vac a few times but doesn't seem to be improving things any further.

Can you offer any further advice?

Thank you!

 

[Elsa TLC]

It could possibly be the cold water gate valve is stuck slightly open.

 

[Burnerman]

Can you concoct some sort of device that will allow you to force fresh, pressurised cold water up through the taps to the loft tank?
John

 

[steve0H]

Can you concoct some sort of device that will allow you to force fresh, pressurised cold water up through the taps to the loft tank?
John

I don't think so, my closest mains cold is downstairs in the kitchen so would have to get a verrrrrrry long hose to get it from there to the upstairs bathroom tap. Kitchen is mixer tap as well but guess wouldn't matter if I just put on cold?
Thought wet vac was supposed to do same thing as this approach but it may be worth a shot.

I didn't adjust any gate valves at all before or after doing the work so don't think valve is a culprit?

 

[Elsa TLC]

Can your vacuum blow?

 

[steve0H]

I'm not sure, I've borrowed it off a mate. It's a Charles (Henry's pal) wet vac if anyone knows if he has this function? Quick Google isn't showing me much info about how to do it if possible!

 

[Elsa TLC]

I'm not sure, I've borrowed it off a mate. It's a Charles (Henry's pal) wet vac if anyone knows if he has this function? Quick Google isn't showing me much info about how to do it if possible!

Charles is straight. Doesn't blow for love nor money. Neither does Henry.

 

[polesapart]

As @Burnerman , kitchen tap to downstairs basin cold tap?

 

[steve0H]

Downstairs basin cold is a weird looking waterfall style mixer tap with like a horizontal opening for the water to pour out from so I didn't think would be possible to get a decent fitting/connection from the hose onto it. Sorry I don't mean to have an excuse for all these helpful suggestions!!
Are we agreeing though most probably air lock still present somewhere? Does it have relevance as to where it is likely to be in the system? I figured must be somewhere upstairs as having such dramatic effect on bathroom basin and toilet when bath is running. Maybe it makes no difference where you try and blast/suck the air out of or does it?

 

[Mottie]

Is the mixer tap mains cold but gravity hot? If so, I’ve got over this in the past by holding my hand over the mixer spout and opening both taps. The mains cold will force any air up into the cold water storage tank.

 

[Burnerman]

I have a hosepipe connected to a washing machine inlet which has helped before....the diameters are different though.
John

 

[steve0H]

Is the mixer tap mains cold but gravity hot? If so, I’ve got over this in the past by holding my hand over the mixer spout and opening both taps. The mains cold will force any air up into the cold water storage tank.

My kitchen sink is mains cold and gravity hot, as is utility room. All others are gravity cold and hot.
Worth trying this on kitchen sink? Hot water all totally fine everywhere!

 

[Mottie]

My kitchen sink is mains cold and gravity hot, as is utility room. All others are gravity cold and hot.
Worth trying this on kitchen sink? Hot water all totally fine everywhere!

Ah, just read your post again. I thought it was the hot water you were having trouble with. Sorry!

 

[Elsa TLC]

Ah, just read your post again. I thought it was the hot water you were having trouble with. Sorry!

It's not your fault. Stop beating yourself up.

 

[Doitproper]

The cheaper service valves have a smaller flow diameter and may be restricting the flow more than previously. Similar if combined tails and service valves have been used. Also, ensure the tails are not kinked or twisted.