Sink Bath cold water take off point?

my3cents · 09-10-2016 02:12PM #1

Cold water for the bath and sink comes from the header tank, thats the obvious bit.

The header tank feeds the bottom of the hot water cylinder, where along that run do you take off cold water for the cold taps?

I'm replacing our hot water cylinder and cold was taken off just before the cold water from the header tank went into the HWC. I was wondering if the connection should be made higher up so its impossible to run the HWC dry and hence keep the immersion element covered in water at all times.

Perhaps I'm over thinking this?

Edit> I really am over thinking this as after posting I then thought I need the tank to drain slightly from the cold to make it easier to change the immersion element.

decmeister · 09-10-2016 02:21PM

the cold water to the hwc should be stand alone?
the cold water to the bathroom and house in general should be totally seperate
so you need to drain the tank and take a seperate connection
the cold feed to the cylinder always goes in the bottom and the hot comes out the top
which keeps the cylinder full at all times. this keeps your coil and immersion safe

my3cents · 09-10-2016 02:24PM

decmeister wrote: »

the cold water to the hwc should be stand alone?
the cold water to the bathroom and house in general should be totally seperate
so you need to drain the tank and take a seperate connection

So are you suggesting that the cold water supply for the sink and bath taps should come from a separate connection to the header tank? One connection from the header tank to the HWC and another one to the cold taps?

decmeister · 09-10-2016 02:32PM

yes thats the proper way

09-10-2016 02:42PM

my3cents wrote:

So are you suggesting that the cold water supply for the sink and bath taps should come from a separate connection to the header tank? One connection from the header tank to the HWC and another one to the cold taps?

Separate hot & cold from attic tank gives you double the water pressure when filling the bath, running the shower or even just filling wash basin with hot & cold water at the same time.
Still see plenty of older houses with a single feed from the tank

my3cents · 09-10-2016 02:48PM

Thats great. Apart from adding a take off from the header tank which is no big deal, I even have the fitting handy, it saves me making 3 joints in a really awkward location at the back of the HWC.

my3cents · 09-10-2016 02:59PM

One other question, re: expansion pipe. Is there a particular size requirement for the expansion pipe out the top of the HWC? Currently its is 3/4" and it would be easier for me to run it straight up and over the header tank in 1/2" is that OK?

Edit> The tank is only heated by an immersion heater.

Dtp1979 · 09-10-2016 03:01PM

my3cents wrote: »

One other question, re: expansion pipe. Is there a particular size requirement for the expansion pipe out the top of the HWC? Currently its is 3/4" and it would be easier for me to run it straight up and over the header tank in 1/2" is that OK?

No leave it 3/4"

my3cents · 09-10-2016 03:06PM

Dtp1979 wrote: »

No leave it 3/4"

Fine, but I can't leave the original pipe as its obviously on its second or third life. Its been bent in every direction and back again + a couple of unnecessary joints. I'll have to use a right angle compression fitting at the top as I can't bend 180 in 3/4" with just a bending spring.

Sink Bath cold water take off point?

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