Hot Water - What's this bit?

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rendezvous

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#197909 17-Jun-2016 12:24

Hello,

Our hot water cylinder makes occasional dripping sounds, like a little is going down the overflow pipe. Now I think I can hear dripping on the roof, I guess someone will have to come and look at it. While investigating what was going on (I didn't work it out), I wondered what this tap thing does? Also, what setting should it be on?

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#1575696 17-Jun-2016 12:32

It might be the mixing thingy (I just made that name up). Modern hot water cylinder temperatures are constant, with no controls. To control the temperature at the tap the hot water at 65c or higher is mixed with cold to prevent burns.

SaltyNZ

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2degrees

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#1575698 17-Jun-2016 12:33

That premixes cold water with hot on its way out to the hot water pipes. The hot water in the tank needs to be very hot - 70 deg+ - to prevent Legionella bacteria. But the water coming out of the hot tap needs to be much colder - usually around 50 deg - to prevent instant scalding.

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#1575699 17-Jun-2016 12:36

Tempering Valve, I think they're called.

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nickb800

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#1575701 17-Jun-2016 12:37

It's called a tempering valve, as described by the comments above

elpenguino

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#1575702 17-Jun-2016 12:39

Try follow the pipes. Could be tempering valve as shown but for mains pressure cylinder there is also a pressure relief, as far as I know anyway

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rendezvous

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#1575706 17-Jun-2016 12:44

Ok thanks SaltyNZ and timmmay

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timmmay

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#1575709 17-Jun-2016 12:47

Mixing thingy, tempering valve, I was pretty close!

In winter we have to have the dial in the shower a lot further around, because the cold water temperature goes down so much in winter. Even to brush my teeth I need a fair amount of warm water otherwise the cold is too much.

lxsw20

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#1575711 17-Jun-2016 12:51

timmmay:

It might be the mixing thingy (I just made that name up). Modern hot water cylinder temperatures are constant, with no controls. To control the temperature at the tap the hot water at 65c or higher is mixed with cold to prevent burns.

Hot water cylinders still have a thermostat to control the temperature of the water in the tank. It's just you need to cool it down once it leaves the tank, as mentioned above it needs to be 65+ to kill legionnaires, but that is far too hot at the tap, hence the tempering valve.

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#1575715 17-Jun-2016 12:56

Mine didn't have any controls I could find, not that you should need to anyway. Yep I know what the valve is for.

richms

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#1575726 17-Jun-2016 13:20

Sometimes they stuff up and only give you tepid hot water and need a whack from a nearby book or something else soft to get the water back being hot again too.

Richard rich.ms

rendezvous

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#1575727 17-Jun-2016 13:21

Cool

I've adjusted it to 4.5/8, that seems to give me fairly hot water at the tap, but doesn't burn unless I leave my hand there for a while.

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cisconz

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#1575728 17-Jun-2016 13:23

The Pressure release valve looks like this

Pressure Release

Also the tempering valve is set to fail cold - so if you only get cold water and your HW Cylinder is hot - that is your issue.

Hmmmm

Shoes2468

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#1575764 17-Jun-2016 14:22

SaltyNZ:

That premixes cold water with hot on its way out to the hot water pipes. The hot water in the tank needs to be very hot - 70 deg+ - to prevent Legionella bacteria. But the water coming out of the hot tap needs to be much colder - usually around 50 deg - to prevent instant scalding.

70 degrees + I dont think so, more like 65 much higher is just wasteful unless your trying to extend the amount of hotwater required

Spyware

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#1575812 17-Jun-2016 15:16

Shoes2468:

SaltyNZ:

That premixes cold water with hot on its way out to the hot water pipes. The hot water in the tank needs to be very hot - 70 deg+ - to prevent Legionella bacteria. But the water coming out of the hot tap needs to be much colder - usually around 50 deg - to prevent instant scalding.

70 degrees + I dont think so, more like 65 much higher is just wasteful unless your trying to extend the amount of hotwater required

Guideline is to have hot water temp 15 degrees higher than temp valve (55).

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#1575939 17-Jun-2016 17:39

Spyware:

Guideline is to have hot water temp 15 degrees higher than temp valve (55).

EECA says 60 degrees at the cylinder.

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