problems with hot water pressure

[mickqc]

started a bathroom today.
there were no isolation valves on the basin so i drained down the cylinder on the landing and the header tank in the attic.
after this we turned the water back on and filled cylinder and tank back up.
the water pressure is nearly non existent.we turned the boiler on hoping this would help but it didn`t.
we undid the union on top of the cylinder and some water came out but not much pressure.
i even pushed a hose pipe down the tank 22mm outlet and blew down put this didn`t help
even tried it down the expansion pipe.
its baffled me alll day.
any suggestion please had to leave the family with virtually no hot water with week end looming.
i have done this lots of times with never any probs.
thanks for help.

 

[mikegas]

you prob have an air lock do you have hot and cold washing machine valves?

 

[mickqc]

was told it was an airlock but still after blowing down vent pipe and tank outlet?
think so in the kitchen, never checked, why i`m intrigued

 

[mikegas]

attatch the washing machine hose off the cold valve onto the hot and open both valves for a few seconds sending the mains down the hot, it will clear your air lock

 

[mickqc]

sound like a plan
cheers

 

[mickqc]

if the washing machine only has a cold supply.
can i do something in the attic maybe T off the cold supply to the tank outlet

 

[mikegas]

just fit a valve

 

[mickqc]

the strange thing is that water was trickling out of all the taps.
on the top of the cylinder just after the T for the vent there was another T with a 15mm on the branch. this was for the shower i think, there was a gate valve after about 150mm of pipe.
you could actually undo this gate valve and pust a pencil in up to the T with no water coming out.
could not understand this at all.

 

[mickqc]

so the cold water has to be injected downstairs then?

 

[mickqc]

anybody understand this

`the strange thing is that water was trickling out of all the taps.
on the top of the cylinder just after the T for the vent there was another T with a 15mm on the branch. this was for the shower i think, there was a gate valve after about 150mm of pipe.
you could actually undo this gate valve and pust a pencil in up to the T with no water coming out.
could not understand this at all.`

 

[PlumbBobBob]

is there a mixer tap in the kitchen? if so you can use that to get rid of the airlock. you get a towel or similar, hold it over the end of the tap turn on the hot then the cold. holding the towel over the end of the tap will send the cold back up the hot to back fill and force the air out. the towel also stops you getting soaked! twenty seconds or so should be plenty.

 

[mickqc]

thanks for help
so the last post i did about the gate valve still tells all that its an airlock.
when we drained the hot water we touched no valves or gate valves.
there is a mixer tap in the kitchen i`ll try this.