Stop Tap Swap...Now pressure Problem in High Rise Flat...HELP!!!!!!

[msw109]

Due to external wheel gate valve not working, I was forced to freeze the pipework just behind the existing stop tap (broken). This stop tap is in 15mm copper pipework straight onto an unequal tee into 28mm copper feed. I froze the bit of horizontal bit of15mm between the 28mm and the existing stop tap and added a compression 15mm stop tap to the pipework about 2 feet further in on some vertical 15mm copper leading to the meter (then back down). Now the customer has noticed that there has been a pressure drop in the flat. Bathroom pipework bangs and the cold is slow on all outlets.Could it be that the cold feed is gravity, and the bore of the stop tap i fitted is smaller than existing therfore causing a flow rate issue or would freezing the pipework next to the existing stop tap have somehow affected it during freezing, causing an obstruction....

HELP!!!!!!!

cheers in advance for all your brain activity

 

[ecowarm]

Air lock if on a tank fed supply caused by taking pipe up and then back down again, if a mains supply post some pictures if possible

 

[msw109]

yeah the meter is on an "upside down "U"" in the 15mm pipework. its all connected by compression elbows. i cracked the first elbow to check the frost plug, then removed part of the pipework on the first vertical part to install the new stop tap, near the top about 6" from the meter. then replaced before plug melted!!!!!! since then there has been a pressure drop and banging in bathroom...... sounds like AIR as you say

 

[ecowarm]

loosen the top elbows slightly to remove the air and see if it helps

 

[markfxy]

check the stopcock is the right way round

 

[Bernie2]

Hmm!

I can't quite make out the question, but on some high rise buildings the cold mains water supply can be store tank fed and so low pressure. Putting a high pressure screw down stopcock on it may cause problems. Probably why it may be a full bore low resistance gate valve that was fitted in the first place.

 

[msw109]

the fullbore gate valve was the external isolation. the internal was just a normal stop tap, end feed, fitted just off the main 28mm. the new stop tap is fitted in the correct direction. the customer has informed me this morning that it has got slightly better so I am leaning towards it being air in the system. makes sense as she is 1 floor down from the top of the building (tanks on roof), therefore the head of pressure would be no more than 10 metres i guess