Recurring airlock? in hot water supply

[grekko]

Over the past 3 or 4 months I have noticed the hot water flow from the bathroom tap reduces daily until it becomes a trickle, the kitchen hot water tap also reduces flow but not the same extent. I am now regularly having to use the washing machine hose connection solution to clear the airlock(?). After applying this regular solution the flow in the bathroom and the kitchen appear to flow with similar pressure, but as days pass I begin to notice that the hot water bathroom pressure/flow is getting less(until eventually it stops flowing) and will almost stop if the kitchen tap is opened at the same time, either over sink or via washing machine or dishwasher. Is there a fairly easy solution or will this require major plumbing servicing.
I have a boiler that heats the water for the storage cylinder and central heating. (indirect?).

 

[grekko]

Could somebody,if my sketch is readable, explain what all the pipes are for, it looks a real heath robinson contraption:

 

[thompsonbrown]

when you clear air lock how long do you connect hose for

 

[WHPES]

Came across a similar problem a couple of years back. Traced it back to the remains of a dead mouse in the pipework.

 

[grekko]

It became unbearable today....the overflow started spewing water out onto the garden again,thinking the hot water had overheated maybe I went to check, NO, it was lukewarm.....went into loft no sign of water entering the cws tank....but full past the overflow. Went down and drained off all the warmish water till the ball cock was low enough to start refilling.......put boiler back on for hot water...3 hours later just warm again from tap but overflow spewing out again.....checked cylinder and it was a lot hotter than water out of taps.....I'm being driven nuts by this, and before anyone advises a plumber each time I've asked for help they each recommended changing ballcock...wouldn't entertain any other reason for overflowing, surely there's a decent plumber who's come across a similar problem....I'm not paying out for another useless ballcock. PLEASE PLEASE HELP.
I think I've added before the reason why I thought it was an airlock, but anyway when the hot water usually runs a trickle (aftr 2-3 days) I blow back cold from the mains into the hot tap for about 30 seconds and that gives temporary relief, but I need to know the fault and solution.

 

[WHPES]

You've got cold water getting into the hot system from a faulty mixer or even washing machine etc somewhere the way I see it.

 

[grekko]

You've got cold water getting into the hot system from a faulty mixer or even washing machine etc somewhere the way I see it.

What puzzles me is this....why should the hot water only run from kitchen/bathroom taps for a day or two until it slows to a trickle or stops if as you say cold water is getting to the hot system, wouldn't the water not get heated up as it usually has until today....cold water forced back up the hot pipe clears the trickle flow temporarily.....just curious.

 

[WHPES]

Dunno, really need someone to come and inspect it to know properly.

 

[Mike Jackson]

If the cistern is overflowing and the ball valve is fine water is getting back into the system some other way. The two most common things are a faulty coil in the hot water cylinder and a faulty mixing valve.

I've lost count of the number of times I've been called to jobs where "plumbers" have insisted that it must be the ball valve. You need someone with a bit of experience and common sense to have a look.

 

[plumb_know]

To see if it is cold mains water pushing back up the hot pipe work from a tap or appliance, see if a plumber can fit check valve on to hot water draw off from cylinder just after vent pipe, temporarily and see if this stops the overflowing problem. If it does then you know the overflowing is caused by mains being pushed back into tank. If it doesn't then you know to look at hot water cylinder. Another thing is have you had anything installed a month or so before you noticed this problem, if you have this could be source of problem. As for the blockage it may be caused from scale in cylinder. I noticed on your diagram you hot water pipe runs back into the loft? Is you cold water tank in loft raised to give good pressure or do you have negative head pump fitted? Hope some of this helps! Where you from as someone from the forum may be able to pop round and help, as its hard to solve a problem without being there.

 

[grekko]

To see if it is cold mains water pushing back up the hot pipe work from a tap or appliance, see if a plumber can fit check valve on to hot water draw off from cylinder just after vent pipe, temporarily and see if this stops the overflowing problem. If it does then you know the overflowing is caused by mains being pushed back into tank. If it doesn't then you know to look at hot water cylinder. Another thing is have you had anything installed a month or so before you noticed this problem, if you have this could be source of problem. As for the blockage it may be caused from scale in cylinder. I noticed on your diagram you hot water pipe runs back into the loft? Is you cold water tank in loft raised to give good pressure or do you have negative head pump fitted? Hope some of this helps! Where you from as someone from the forum may be able to pop round and help, as its hard to solve a problem without being there.

We're in the Liverpool area Plumb_know.

 

[gassafe]

Looking forward to hearing the how you got in with this Grekko!!!

I hate finding an old thread of interest, reading 3 pages and it all stops!!!