Thread: Kitchen sink mixer - hot water pressure is low

Originally Posted by russ57

The cap looks like a blank for a spare outlet. The whole lot looks a bit untidy.

Is that just an elbow right at the top?
Id remove the pipe from the stopcock, put a hose on it, and see if there is full flow there.

Yes elbow right is the hot water to the mixer.
Is the green valve where I should put the hose?
Above or below?
If so I’d need to stop the house water supply.

Originally Posted by droog

Swap your hot cold flexible feed connections.
If flow is still low on the hot side it’s somewhere else in the plumbing.
I bet it will now be low flow on the cold side indicating it’s in the Flexi or most likely in the feed orifice on the bottom of the mixer right where the Flexi screws into the mixer body.

PS, man that’s a mess of adaptors and fittings. Remove 80% of them and make the whole setup a lot neater.

Yes switched them over and result as described.
As in low pressure now on the cold.
My conclusion is that the blockage is not in the flexies nor the mixer.

Originally Posted by rwbuild

Im not surprised you got low pressure on the hot, there's more twists and turns than a politicians promise.
Remove all fittings from the brass tee, put a nipple in each outlet of the tee, put a mini cock on each nipple, connect flick mixer to one and dishwasher to other, it eliminates several restrictive bends/friction.
The worst enemy of those flexi hoses are bends that are too small in radius, you need as straight as practical connection with large radius bends

My next logical test would be to confirm it’s the copper fitting between the top right red tape and the bottom right red tape.
By unscrewing the connection at the bottom right red tape.
Aim the end into the bucket and back flush.

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Originally Posted by barrysumpter

Yes switched them over and result as described.
As in low pressure now on the cold.
My conclusion is that the blockage is not in the flexies nor the mixer.

I am totally not following here.
Original problem was low hot flow, swapping the Flexi feed (as I described) between hot and cold results in low cold flow.
Conclusion is it’s not in the Flexi or mixer ?


Maybe I am misunderstand what you say you have swapped.

Sure. I'll have a go at my reckoning.

The hot supply has reduces pressure no matter which flexi to the mixer it's flowing thru.

Referring to the pics:
The top red tape on the top right connection is the hot water supply with the red speckled flexi.
The blue speckled flexi is the cold water supply.

I just switched those two flexie connections.

So no matter which side ( hot or cold flexi ) the hot water is flowing from, the hot water has reduced pressure.

Originally Posted by barrysumpter

Sure. I'll have a go at my reckoning.

The hot supply has reduces pressure no matter which flexi to the mixer it's flowing thru.

Referring to the pics:
The top red tape on the top right connection is the hot water supply with the red speckled flexi.
The blue speckled flexi is the cold water supply.

I just switched those two flexie connections.

So no matter which side ( hot or cold flexi ) the not water is flowing from, the hot water has reduced pressure.

Got it, this bit made me think it changed to the cold feed "As in low pressure now on the cold"

These do not look like a normal T fitting, I suspect they may be pressure reducers. Try swapping them over.
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Further to my earlier post, I assume that you have checked the isolation valve at the hot water tank itself just in case someone has turned it down a bit also has there been any building works near by or fire brigade activity with hydrants as this often results in disturbed sediment in the mains lodging your plumbing lines.
I also strongly suggest you do what I described in my earlier post and I reasonably confident that the source of your problem will be found in the process

Those two elbows pointed out above.
Do they have arrows showing the direction of flow? My google-fu finds reducing valves looking similar, but the flow should be in the opposite direction.

Do you have particularly high water pressure? Or a big difference between hot and cold.?

Connect the hot flexi directly to the stopcock.

Originally Posted by rwbuild

Further to my earlier post, I assume that you have checked the isolation valve at the hot water tank itself just in case someone has turned it down a bit also has there been any building works near by or fire brigade activity with hydrants as this often results in disturbed sediment in the mains lodging your plumbing lines.
I also strongly suggest you do what I described in my earlier post and I reasonably confident that the source of your problem will be found in the process

Thanks again.

I'll check the isolation valve on the hot water tank.
We had a new one install not to long ago.

Lots of council sewage works nearby.

Thanks heaps for all the support.
I'll have a go at your previous complex suggestions when all other DIY attempts have been made.

Not sure if this pic will help.

Originally Posted by russ57

Those two elbows pointed out above.
Do they have arrows showing the direction of flow? My google-fu finds reducing valves looking similar, but the flow should be in the opposite direction.

Do you have particularly high water pressure? Or a big difference between hot and cold.?

Connect the hot flexi directly to the stopcock.

Thanks heaps,

The water pressure to the mains is decently strong.
We discussed putting a reduce on the mains to keep my high pressure sprayer from breaking the safety fitting. Too expensive. and have resulted is using a barrel to relieve the back pressure.

Confirming the stopcock is the (main?) fitting at the wall.
Will see if the flexi is long enough to reach the stopcock.
If not I'll need to exhaust all other DIY before investing in more plumbing that I won't be using after the testing.

For my 2 cents worth, you might want to check the tap washer in the stop cock to see that it’s not swollen or disintegrated. (personal experience).

I would think that you only need one stop cock and a longer flexible fitting to make it simpler. Those flexible hoses only need to be not much more than hand tight otherwise the rubber seal will start to choke the flow.

That's a fitting I have never seen in my 50+ yrs of building, who fitted that and why? was it fitted when the dishwasher was installed but you or someone has swapped the dish washer and sink hoses around, does seem to be a restrictor of some sort.
If you need a longer flexi hose to do as per my original suggestion, you can get a short one and add to it.

Originally Posted by apple8

For my 2 cents worth, you might want to check the tap washer in the stop cock to see that it’s not swollen or disintegrated. (personal experience).

I would think that you only need one stop cock and a longer flexible fitting to make it simpler. Those flexible hoses only need to be not much more than hand tight otherwise the rubber seal will start to choke the flow.

That freakin' stopcock is a lot of mucking around.

Yeah, don't know why but tightened just enough to stop it dripping.