No hot water at home unless you turn on two hot taps/showers

Forums › Home Workshop DIY › No hot water at home unless you turn on two hot taps/showers

blachel

10 posts

Wannabe Geek

#148763 30-Jun-2014 15:37

I had the hot water running all good until we had a local power outage. I noted since the outage that I would only get warm or cold water if I have only one tap/shower on hot. The hot water would only come after you turn on a second tap/shower in the house. Once the hot water came through, I can turn the second tap/shower off and the water will remain on hot. If both taps are off and we needed hot water in an hour, I had to had two on again.

All taps are cold/hot mixed onse. I have turned the water cyliner on and off a few times byt that doesn't fix the problem. There was a leaking at the swatch to the cyliner which has been fixed but it didn't solve the hot water problem. I have had plumbers around for other jobs and none figgured out what was the deal with this one but all said it shouldn't have anything to do with the outage...

Anyone have any clue as what this problem is and how to fix it?

with many thanks

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4123 posts

Uber Geek
Inactive user

#1077112 30-Jun-2014 15:42

It might be a sticky tempering valve, you will see this near the HWC it has hot in one side and cold in the other, it mixes the two to a lower (safe temperature) You could try running a tap and giving the valve a firm tap or two to see if the hot then starts to flow from the tap. I would have thought a plumber would have thought to check this.

Niel

3267 posts

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#1077202 30-Jun-2014 17:06

Do you have a low pressure gravity fed system? Is there an air lock in the pipes because of poor pipe routing/modifications? Maybe could happen if a tap was opened while the power was out and a booster/pressure pump was not running.

You can never have enough Volvos!

pctek

807 posts

Ultimate Geek
Inactive user

#1077213 30-Jun-2014 17:44

You need to find out how both hot and cold are fed and then rectify, they must be relatively equal

richms

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#1077344 30-Jun-2014 21:20

Friend had this, lousy hot temperature, long time to come to temperature at the tap and sometimes it would be tepid and then BAM go to an acceptable temperature which is no fun when you are showering.

It was the tempering valve.

Seems they are designed to fail that way rather than just letting thru the hot water.

Richard rich.ms

Disrespective

1925 posts

Uber Geek

#1077590 1-Jul-2014 09:04

Do your taps have thermostatic valves in them? Might also be something to look at there. Unless they're pretty new they won't have them.

gzt

17120 posts

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Lifetime subscriber

#1077620 1-Jul-2014 09:54

blachel: Anyone have any clue as what this problem is and how to fix it?

Yup. How about responding to the questions above so the problem can be narrowed down a bit.

blachel

10 posts

Wannabe Geek

#1077859 1-Jul-2014 13:33

Thank you guys very much for your response and sorry about the late response.

I was trying to find the tempering valve last night with no luck. There are few things there, where two I know are water switch. One looks like the presure valve that makes noise when I get tap/shower on. I can turn it freely both ways and the sound changes. There is another bulky thing which I can not turn at all, it is located between the water intake and the presure valve.

I got some photos but is struggling to resize them for upload... I'll see if I can get them uploaded tonight.

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blachel

10 posts

Wannabe Geek

#1078706 2-Jul-2014 15:28

I have got some photos here. Could anyone please tell me which one is the Tempering Valves

gzt

17120 posts

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#1078711 2-Jul-2014 15:33

Is the system still leaking in places?

In the photographs the system appears to be leaking in many places.

blachel

10 posts

Wannabe Geek

#1078727 2-Jul-2014 16:01

gzt: Is the system still leaking in places?

In the photographs the system appears to be leaking in many places.

No the leaking has been fixed. The photos were taken before it got fixed.

wongtop

563 posts

Ultimate Geek

#1078733 2-Jul-2014 16:06

Pretty sure the tempering valve is the silver valve at the top left of your centre picture (cold and hot inlet and hot outlet).

nickb800

2716 posts

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Trusted

#1078738 2-Jul-2014 16:08

I think the tempering valve is the top-left one in the second and third photo (in the middle of the insulated pipe run). Although I'm not sure what the black capped valve attached below it does

blachel

10 posts

Wannabe Geek

#1078744 2-Jul-2014 16:18

wongtop: Pretty sure the tempering valve is the silver valve at the top left of your centre picture (cold and hot inlet and hot outlet).

Thank you wongtop, I'l try to tap it and see if it fix the problem.

blachel

10 posts

Wannabe Geek

#1078746 2-Jul-2014 16:19

nickb800: I think the tempering valve is the top-left one in the second and third photo (in the middle of the insulated pipe run). Although I'm not sure what the black capped valve attached below it does

Thnks Nick, I think that's the presure valve as it makes sounds and the sound changes when i spin it...

andrewNZ

2487 posts

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Inactive user

#1078759 2-Jul-2014 16:44

FYI, the bulky component on the incoming pipe (centre of the third photo) is the Ajax valve. It regulates the incoming water pressure.
If you adjust this valve one of two things happens.

Your hot water pressure gets worse
You overflow the hot water onto your roof constantly meaning you'll possibly have no hot water and a huge power bill.

The silver one is the tempering valve. It has hot water from the cylinder on one side, cold water from the supply at the bottom, and feeds the taps on the other side. The black valve below the tempering valve is probably a regulator to adjust the temperature at the tap.

I suppose there is a chance that the tempering regulator has been adjusted and is causing this. The way my mind sees it, it could fit your symptoms exactly. BUT, I'm not a plumber.

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