# Forum Home Renovation Plumbing  Replacing the Non Return Isolation Valve (connecting to Electric Hot Water Heater)

## g00se

Hello, 
I am in Australia. My hot water system is set up pretty much as shown in this diagram:  http://www.nefa.com.au/media/40066/i...chematic-1.jpg 
The Non Return Isolation Valve is leaking from the tap mechanism on it. I'm presuming this means it needs to be replaced. 
I'm also presuming though, that once this valve is removed, water sitting in the hot water tank will come gushing out from the inlet pipe? 
I guess what I'd like to know is, what is the procedure to change this valve? 
Thanks  :Smilie:  
Goose.

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## commodorenut

Yes, the water will come gushing out. 
You need to turn off the power to the HWS at the meter box.
Then turn off the water at the meter. 
Then relieve the pressure in the tank by pulling the relief valve, or turning on a hot tap until it no longer runs.   
Then undo the valve - but be careful, as the water will be hot, and you'll need to stand back & let it run, and cool down before you can work on the area. 
Swap the valve over, and turn on the water - check for leaks.  Let the tank fill - leave a hot tap open, or hold open the relief valve to bleed as much air out as possible - close the tap when it runs 100% water. 
Then turn the power back on. 
If it's off peak, there's a little switch you can (illegally) flick up to power it up without waiting for the next off-peak period.

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## Snipper

It's not illegal to boost your hw is it?  Just costs more as its peak rate.

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## plum

There is no need to turn the power off to the unit, and there is no need to drain the unit! Once the pressure is released from the cylinder, the tank is actually in a vacuum state, with very little water loss. Just take note that the valve purchased may not necessarily be a straight swap.

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## NRB

plum is correct,easy job

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## g00se

Thank you everyone for your replies! It is very much appreciated.   

> There is no need to turn the power off to the unit, and there is no need to drain the unit! Once the pressure is released from the cylinder, the tank is actually in a vacuum state, with very little water loss. Just take note that the valve purchased may not necessarily be a straight swap.

  About releasing the pressure from the cylinder, I take it you mean I should open the pressure-temperature relief valve (and/or the taps in the house ? ) before I detach the inlet pipe?

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## Bros

In addition to the above I would run it for one or two days without power to reduce the cylinder temperature as that water can scold you. When you are doing the job make sure no one uses the HW tap anywhere in the house as this will destroy the vacuum lock.

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## plum

> Thank you everyone for your replies! It is very much appreciated.   
> About releasing the pressure from the cylinder, I take it you mean I should open the pressure-temperature relief valve (and/or the taps in the house ? ) before I detach the inlet pipe?

  Yep.

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## g00se

> Yep.

  Thanks Plum, the only thing is "Bros" above said that if tap is turned on then vacuum lock will be lost .. ?

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## Bros

Plum was saying how to reduce the pressure in the cylinder and then all valves have to be shut and not opened until the job is complete.

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## g00se

Thanks folks, that makes sense. 
Please let me know if this method is sound: 
1. Turn off electricity to HWS (I realise this isn't completely necessary, but will do for safety's sake) 
2. Drain some of the hot water by having a shower, dishwasher, etc. This is so that cold water fills into the bottom of tank and so if some water comes out when the inlet is detached then it will be cooler (do this instead of waiting days for the water to cool down). 
3. Run the TPR valve for 30 seconds to release pressure 
<make sure at this stage that no hot water taps are on> 
4. Turn off mains water 
5. Detach the inlet pipe, and replace faulty Non Return Isolating Valve. 
6. Re-attach the inlet pipe 
7. Turn on mains water 
8. Operate hot water tap(s) in house for 1 minute.  
10. Ensure that there are no leaks in replaced/reassembled items.

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## Bros

:Iagree:

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## plum

> 

  Except maybe swap 3 and 4 around. And maybe before you do anything, CALL A PLUMBER.    :Wink 1:

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## Marc

I agree wholeheartedly. The best method and the legal one is _call a plumber ..._ ha ha  :Smilie: 
Well what do you know I said it !
Probably a $200 job.

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## g00se

Thanks for all the help folks. Don't mind at all getting the right person to do the job, just as long as it's done properly, at a fair price, and with decent materials. I'll do some looking around.

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## SergeyAU

Hi guys.
How does this method apply to Solar HWS? Its an old house, where Solar HWS is on the roof and valve is on ground floor (maybe its the standard). 
I will have it replaced by the plumber. The guy said it will be expensive, but if I buy the valve he will do it together with other things.
Just want to prepare the system for him to work on, so that its ready to replace when he comes (time = money). 
This is the valve that I currently have (leaking). This looks like RMC trio valve, which costs about $80 from my local plumbing shop.  
I was going to buy this one from Bunnings for $25 as the guy said he will make it fit.  
But I am now thinking if its OK quality to replace? Should I go RMC one or this one from AVG for $50?

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## g00se

SergeyAU, My NR Isolation Valve looks exactly the same as yours, and I was also considering the same replacements. I haven't changed mine over yet. I'll be interested to know how much the job ends up costing you.

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## ringtail

> And maybe before you do anything, CALL A PLUMBER.

  geez that took longer than usual  :Biggrin:

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## g00se

Yes call a plumber. And we may as well also close down these forums since why waste or time when the plumber has all the expertise necessary  :Smilie:

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## SergeyAU

> SergeyAU, My NR Isolation Valve looks exactly the same as yours, and I was also considering the same replacements. I haven't changed mine over yet. I'll be interested to know how much the job ends up costing you.

  I do not know the separate cost to install it. The guy said he only charges labor cost. He'll be doing a lot of things (replacing kitchen), so will do the valve as well.
I can only guesstimate, that if the actual part cost $85, and they minimum an hour of labor (which is about the same), then its $170 already

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## Bros

What did you store near it as I haven't seen fittings in that condition.

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## SergeyAU

Nothing. Its in the carport under roof. I think the tap might have been leaking for years without my parents noticing it. It was leaking and now it stopped, so my folks are saying - better not touch it. But its going this friday. I got RMC tap from Masters ($33). A bit shorter and without a strainer. Hope the guy can make it fit

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## jjjarrett

$85 an hour for the plumber, better keep him.

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## Marc

> geez that took longer than usual

   I have a lot of fun reading this and the electric forum. The number of questions, with the qualifier "before the plumber/electrician comes" is something else. 
As far as the isolation valve in question, 
a) if it is not leaking don't touch it just like someone's parents said...not sure who is who 
b) If to save $50 you buy a shorter valve and the pipe is straight on both sides, your saving will turn into a $100 additional work to fit a shorter valve. May be $200.

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## SergeyAU

Plumber was in yesterday. Only disconnected water pipes and gas. Said he will come back to do more once we demolish the kitchen. 
Did not take any money.
I will update on the total once done.

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## plum

> geez that took longer than usual

  Yes, but I was happy to answer earlier questions, but when he got the order of doing the job out of whack, I then thought, maybe he shouldn't do it.

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