Water going hot-cold-hot-cold. Boiler? Worcester Greenstar 30si

HUMBUG

JimmyChanga wrote: »

If you have the tap fully open the water may not be as hot but it should be constant.

As for cleaning the filter weekly - well, the heating flush wasn't done thoroughly enough.

You might have misunderstood the plumber who changed the washer on the hot tap. You central heating water is not connected to the hot tap's supply. But he may have isolated the cold water feed to the boiler. Therefore no water to hot taps that come off the combi.

Many thanks for your reply. So is the central heating water pressure regulated by a pump in the boiler (ie. the cold water mains pressure isn't used to assist the pump)?

With regards the leaking HW Tap, I think you are right about the isolation of the cold water feed to the boiler (not sure I saw him doing that to be honest- he certainly didn't turn the cold water mains off). Can one just switch off the boiler at the electrical socket? Would that have stopped water feed into boiler?

My sister followed the advice of our plumber above regarding the hot/cold water fluctuations and it didn't work . My sister thinks switching on the 'Preheat' function on (before they use the mixer taps in the bath) might be the only option . Then to save gas , switch it back to ECO mode . This is not an ideal situation and now I'm wondering whether we should have gone for a normal condensing boiler using a sealed vessel and retaining the hot water tank. Does seem like a lot of wasted water using a combi boiler although I've read about a device called 'Combisave' which might be worth considering.

JimmyChanga

Many thanks for your reply. So is the central heating water pressure regulated by a pump in the boiler (ie. the cold water mains pressure isn't used to assist the pump)?

It's a sealed system. The amount of water in it creates the pressure. It is initially filled and then topped by the cold mains water through a one way valve.

With regards the leaking HW Tap, I think you are right about the isolation of the cold water feed to the boiler (not sure I saw him doing that to be honest- he certainly didn't turn the cold water mains off). Can one just switch off the boiler at the electrical socket? Would that have stopped water feed into boiler?

At the point the cold mains enters the boiler there is usually a lever that just has to be shifted a quarter turn to isolate it.

My sister followed the advice of our plumber above regarding the hot/cold water fluctuations and it didn't work . My sister thinks switching on the 'Preheat' function on (before they use the mixer taps in the bath) might be the only option . Then to save gas , switch it back to ECO mode . This is not an ideal situation and now I'm wondering whether we should have gone for a normal condensing boiler using a sealed vessel and retaining the hot water tank. Does seem like a lot of wasted water using a combi boiler although I've read about a device called 'Combisave' which might be worth considering.

You need to speak to the installer and get what was promised. Did you pay for a proper power flush?

HUMBUG

Yes , we paid for a Powerflush as part of the installation . I must admit there was lots of sludge in the system even after 4-5 hours (ie. the water was still a bit cloudy). The engineer said there was no way one could completely get all the sludge out of the system.

Thanks for the info about a lever that can be used to isolate the
water mains flow into the boiler (it should be easy to locate - I hope). Our bath cold water tap has now developed quite a drip/trickle so I might have a go at changing the tap washer without having to shut off the mains. Should I also have to switch off the boiler?

JimmyChanga

Thanks for the info about a lever that can be used to isolate the
water mains flow into the boiler (it should be easy to locate - I hope). Our bath cold water tap has now developed quite a drip/trickle so I might have a go at changing the tap washer without having to shut off the mains. Should I also have to switch off the boiler?

Only the hot taps working off the combi can be isolated that way. The cold taps will be working off mains pressure directly so will have to be isolated from mains or if any valve is located near the tap itself. Of course there's also the chance taps or toilets etc could be working off water tanks too depending on how a property has been plumbed. Make sure you've checked it's stopped running, apart from the small amount that will be still in the pipe, before you do anything!

But do turn the boiler off as well. Once everything is fixed open the mains cold, purge all air at hot and cold taps and then put the boiler back on.

HUMBUG

JimmyChanga wrote: »

Only the hot taps working off the combi can be isolated that way. The cold taps will be working off mains pressure directly so will have to be isolated from mains or if any valve is located near the tap itself. Of course there's also the chance taps or toilets etc could be working off water tanks too depending on how a property has been plumbed. Make sure you've checked it's stopped running, apart from the small amount that will be still in the pipe, before you do anything!

But do turn the boiler off as well. Once everything is fixed open the mains cold, purge all air at hot and cold taps and then put the boiler back on.

Many thanks again for all the advice. Yesterday was one terrible day because there was a massive leak in my parents place . My sister phoned me at 10:30 pm saying water was pouring through the ceiling and didn't have a clue what to do (elderly parents also in a high state of panic). I told her to switch off the lights and try to turn off the mains outside (but she didn't know how).

I ran back to my parents place and managed, after great difficulty, to prise open the cast iron lid covering the stopcock and then managed to turn off the water supply.

The inside dining room area was flooded but the ceiling thankfully intact. The leak was coming from the bathroom where that original plumber had changed the hot tap washer the previous day. My sister said she could hear a hissing noise coming from under the bath (whose side panels were all tiled up over hardwood) while the water was pouring downstairs.

I phoned the Building Insurance Emergency number and they said a plumber would only come out once I had paid them a £25 call out fee (which I did over the phone). That he would try and isolate the leak but not if it was enclosed by cabinets , inside a wall , etc .

I therefore had no choice but to start demolising the tiles and hardwood at 12pm to gain access to the hot/cold water pipes under the bath. When I finally gained access (after cutting myself on a sharp piece of tile) , I could see that there was some water but I couldn't see where the leak originated from. I was going to turn the mains back on slightly to trace the leak but the only torch in the house suddenly failed and I just couldn't see what I was doing in the dark.

Anyhow , to cut a long story short, the plumber arrived and traced the leak to the flexible hose connector (to hot water tap) which had burst. He said that one reason could be the fact that the hot water pipe was sort of suspended and not braced . That the combi -boiler pressure may have vibrated that pipe (when the hot water tap was turned on) enough to cause a failure in the hose. That I should try and provide support under the pipe with a piece of wood or a brick (which I have done now).

But now I think his reasoning may have been flawed after reading this article below.

https://plumbingconnection.com.au/bursting-the-flexi-hose-bubble/

Seems to suggest that 'flexible-hose connectors ' are a ticking time-bomb and might be good practice to change them at least every 5 years. The hose that burst in my parents place must have been over 20 years old. I think I'll give them a miss the next time I have any taps replaced even if it means a bit more expense having proper copper pipework cut and installed.

Now I am completely paranoid about these flexible hose connectors and just waiting for the 'bomb' to go off

JimmyChanga

Now I am completely paranoid about these flexible hose connectors and just waiting for the 'bomb' to go off

He's right about the movement causing issues. Pipes should be clipped where possible. I'm not a fan of flexi-hoses either.

I wouldn't worry too much. Many times they are installed kinked and/or then the braiding is attacked by water leaking through the tap hole causing the rubber hose to become compromised. But it's not that common in my experience.

If you look up anything on the internet as a problem, you're going to find it. If you are worried I would replace with copper or plastic pipe where possible.

HUMBUG

JimmyChanga wrote: »

He's right about the movement causing issues. Pipes should be clipped where possible. I'm not a fan of flexi-hoses either.

I wouldn't worry too much. Many times they are installed kinked and/or then the braiding is attacked by water leaking through the tap hole causing the rubber hose to become compromised. But it's not that common in my experience.

If you look up anything on the internet as a problem, you're going to find it. If you are worried I would replace with copper or plastic pipe where possible.

Just found another leak under the bath

But this time its a really tiny slow leak on the cold water pipe. Also the pipe is covered with a 2 inch layer of white chalky cottage cheese looking material. Almost as if the slow leak has built up layers of calcium deposits over many years (could be more than 30+ years).

Might be another £150 quid on a plumber call out in the next few days.:(