Air-lock?

[Ric_01]

Hi,

Due to a suspected air-lock, I had the plumbers in the other day.

They did an all-over job looking for the culprit which was choking off the water, first the hot, then the cold. Water from the outdoor mains tap was unaffected, so it was an indoor issue.

They thought the job would take 30 mins - 1 hour, it took 3 hours. They cleaned out the upstairs tank, replaced the ball-cock, drained the immersion tank, tested every single tap in the property, but still couldn't get the hot water flowing, it would start, then drop off in flow, to nothing.

After about 3 hours, I went into the kitchen

, where they were working, & noticed the hot tap was running. I looked down & saw they were draining from a white hose, about a bucket-full of clear water (no scaling sediment - which they had earlier pointed the finger at, as a possible cause).

After that, water back to normal. So I asked them what they did? Could get no straight answer.

Here's the picture - I spotted the white hose under the sink - did they drain this pipe to clear an air block please?

Thanks

Ric

 

[denso13]

That's probably the cold to the washing machine, so unlikely.

 

[CountryFan]

Unless they were backfilling the system, then as above, unlikely.

 

[Ric_01]

That's probably the cold to the washing machine, so unlikely.

The issue more or less began with the washing machine, I was having to fill it with 10 litres of water, every time it needed it, or it would just stop, & flash a red error message. As soon as enough water was poured in, the machine carried on as normal.

 

[Ric_01]

Unless they were backfilling the system, then as above, unlikely.

But why would they drain the washing machine, which had drained itself, at the last rinse, when it was last used, please? There was a *lot* of water coming out of that white hose, enough to fill a bucket.

 

[denso13]

There was a *lot* of water coming out of that white hose, enough to fill a bucket.

It is the water hose supplying the machine, if you have the valve open then you can fill as many buckets as you like.

 

[CountryFan]

But why would they drain the washing machine, which had drained itself, at the last rinse, when it was last used, please? There was a *lot* of water coming out of that white hose, enough to fill a bucket.

I don't know why they would do that, but the opening post was about a lack of hot water on an open vent system. As above, if it was open or even passing, fill as many buckets as you like.

 

[Razor900]

They probably looped a wm hose back to the redundant hot tap in the picture.

Then backflushed it. When they took the hose off the mains side they pulled a load of water through the hot.

It may or may not work in the long term

 

[Ric_01]

It is the water hose supplying the machine, if you have the valve open then you can fill as many buckets as you like.

But if you look at the photo, the white hose must have been taken off the mains pipe, coming off the floor

 

[Ric_01]

They probably looped a wm hose back to the redundant hot tap in the picture.

Then backflushed it. When they took the hose off the mains side they pulled a load of water through the hot.

It may or may not work in the long term

They were definitely popping their own hoses on & off taps, presumably hoping to clear an air-lock? Prior to this, they were pointing a finger of blame at the water-softener, saying it was probably not working. So, silt in the pipework. But I said I fill the softener regularly, & it dissolves all the salt tablets in there. That salt must be going somewhere? The fact that they cured, first the cold flow, then the hot, suggests that the water softener unit was not the culprit. There was a *lot* of head-scratching going on - it took 3 hours to sort whatever was causing the problem.

 

[Johntheo5]

They thought the job would take 30 mins - 1 hour, it took 3 hours. They cleaned out the upstairs tank, replaced the ball-cock, drained the immersion tank, tested every single tap in the property, but still couldn't get the hot water flowing, it would start, then drop off in flow, to nothing.

View attachment 418582

On the very rare occasions that my CWSC has run dry, there is always a airlock in the hot side once the CWSC has refilled, don't know if its in the CWSC supply or in the HW outlet to/from the HW cylinder, My mixing taps are mains cold and gravity hot where the mixing takes place in the spout. To clear the airlock, I just put my finger over the diffuser (spout) outlet, open the hot tap first, then the cold, this clears the airlock in a few minutes.

 

[Ric_01]

Yes, I have the same. Water tank in the roof, cold water from the mains. However, there is an immersion tank in the airing cupboard, I do not understand the relation of the immersion tank, to the water tank above it, in the roof.

The immersion tank has an element, which is never turned on, because the boiler in the kitchen is gas-fired.

How do you avoid being scolded when you open the hot water flow please, mine comes out red-hot.

 

[Johntheo5]

The immersion tank is the HW cylinder which is supplied from that water tank...the cold water storage cistern (CWSC) In the attic, it is normally heated, like yours, with hot water from the boiler circulating through a coil in the cylinder or with a electric heating element, the immersion. The water in the cylinder is normally heated to 60C for legionella protection and reduced to a user friendly 35/45C by adding cold water in a mixer. The 60C is normally controlled by a cylinder thermostat which opens/closes a motorised valve in the coil inlet which in turn will demand the boiler to fire on/off as required. The immersion has its own separate thermostat.

 

[Razor900]

How do you avoid being scolded when you open the hot water flow please, mine comes out red-hot.

I presume you mean when trying to get rid of the air lock?

If you haven't run any hot water for half an hour or so the tap will be cold. As John says block the outlet then turn the hot tap on before slowly turning on the cold.

There is a lot more pressure in the cold so it will force water back up the pipe, hopefully pushing any air out and when you let the tap run afterwards it should bring any left over air with it

 

[Ric_01]

That is helpful - thank you - plumbing is a mystery to me, I'm here to learn.

Btw, there have been multiple scenarios since I moved here, for the property to be isolated from the mains water. Not one plumber / engineer has ever been able to locate the stop-cock under the sink. They all head for the water meter point, under the pavement, by the roadside. Sometimes they complain that they haven'y got the right key to operate that either, or that the meter assembly is flooded / loose, so the key can't be operated. Chaos. I got onto the local water board, who grudgingly agreed to send someone out, to inspect the roadside meter.