Replace pipes under kitchen sink

bluestrattos · 30-04-2021 12:01AM #1

Hello,

I plan to replace the pipe (going up) by removing it from the yellow mark, add an isolation valve, and then connect to the tap hose pipes.

To measure the correct size, would measuring the outside (in the yellow mark) with caliper be enough ?

Thanks

CaptainCoPilot · 30-04-2021 12:07AM

Its half inch pipe.

If you replace with pex pipe dont forget inserts and you will need new olives too.

Be careful OP the cold is mains pressure. Unless you are confident at this you could end up with a nasty leak.

greasepalm · 30-04-2021 12:11AM

One issue we had in our old kitchen was old plumbing was a different size than the newer like olives were loose on pipe.

bluestrattos · 30-04-2021 04:50PM

CaptainCoPilot wrote: »

Its half inch pipe.

If you replace with pex pipe dont forget inserts and you will need new olives too.

Be careful OP the cold is mains pressure. Unless you are confident at this you could end up with a nasty leak.

Thanks CaptainCoPilot, I didn't took that in consideration regarding the mains pressure. There's 2 isolation valves in the cold water pipe coming from the mains (for dishwasher and washing machine)

, does that mean the pressure is actually ok, or if I introduce another, I'm just creating problems in the future ?

greasepalm wrote: »

One issue we had in our old kitchen was old plumbing was a different size than the newer like olives were loose on pipe.

This is a 2005 construction, so yes I imagine I may face similar problem

CaptainCoPilot wrote: »

Its half inch pipe.

If you replace with pex pipe dont forget inserts and you will need new olives too.
[...]

Instead of that type, could I just use something like this ?

I'm not 100% familiar how to fit that pipe, I imagine it would be easier with these type of connectors.

listermint · 30-04-2021 04:53PM

No idea but that socket scares me. Is there a sink waste processor or something or why is there a socket there.

Also the only isolater shown in your picture for the cold is the dishwasher. You need to locate isolator for the cold before that. It may actually be outside in garden or footpath if it's not under the sink

bluestrattos · 30-04-2021 05:16PM

listermint wrote: »

No idea but that socket scares me. Is there a sink waste processor or something or why is there a socket there.

Also the only isolater shown in your picture for the cold is the dishwasher. You need to locate isolator for the cold before that. It may actually be outside in garden or footpath if it's not under the sink

The other one is hidden behind the sink waste pipe, but you can see on the right the grey hose. The socket is for the dishwasher.

the valve to close the cold water that I imagine is coming from the mains, since it's a larger valve and pipe it's just below

CaptainCoPilot · 30-04-2021 06:13PM

Flexi pipes will work but they aren't a brilliant long term solution. You would be better served using solid pipe.

You will need to turn off the water at the stopcock which is the one near the waste pipe. You will need to turn off the hot water in the hot press to connect that one.

2005 construction you wont have problems with sizing, its half inch. The threads will be bsp on the fitting you are connecting to.

To be honest this is a small job for a plumber and wouldnt be expensive. What I mean by proceeding with caution is with mains pressure you need to be more sure of your connections. You dont want a leak. Water is the enemy inside the house.

greasepalm · 30-04-2021 08:17PM

Do i not see a red tap with no blanker fitted?

bluestrattos · 04-05-2021 12:18PM

CaptainCoPilot wrote: »

Flexi pipes will work but they aren't a brilliant long term solution. You would be better served using solid pipe.

You will need to turn off the water at the stopcock which is the one near the waste pipe. You will need to turn off the hot water in the hot press to connect that one.

2005 construction you wont have problems with sizing, its half inch. The threads will be bsp on the fitting you are connecting to.

To be honest this is a small job for a plumber and wouldnt be expensive. What I mean by proceeding with caution is with mains pressure you need to be more sure of your connections. You dont want a leak. Water is the enemy inside the house.

Thanks for the tips.
I would prefer to have a plumber, as I will be replacing the sink as well, but plumbers are in short supply (I even tried to check Metac to join a basic plumbers course), but I'll see how it goes. That last thing I want is a leak.

greasepalm wrote: »

Do i not see a red tap with no blanker fitted?

Yes, you're correct, but to be fair, there's no kids, and the cats haven't been able to switch that valve on, so I'm too worried. But since I'll be touching the pipes, I will probably handle that issue.
Thanks

K.Flyer · 04-05-2021 03:52PM

bluestrattos wrote: »

Thanks for the tips.

Yes, you're correct, but to be fair, there's no kids, and the cats haven't been able to switch that valve on, so I'm too worried. But since I'll be touching the pipes, I will probably handle that issue.
Thanks

Just take the Red handle off the washing machine valve, put the screw back into the stem and using a piece of string or a cable tie leave the handle attached to the pipe in case you need it some day. That way it can't be accidentally turned on.

dathi · 07-05-2021 09:45AM

you will need to turn off the hot and cold water to do this work . cold water stop is in one of your pictures hot is probably in hot press . as you are doing work there you should remove the red washing machine valve by removing the T joint and replacing it with either a straight joint or a penny valve. as washing machines are no longer supplied with a hot water inlet

Replace pipes under kitchen sink

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