Thinking of having a mains pressure cylinder put in (by plumber) At present we have a header tank. The pipe work seems to be copper and the house is approx 32 years old. Will the old pipe work handle this pressure or do I need to have this replumbed to be on the safe side? Is this a common problem? Of course some pipe work is hidden.
zak410,
Sep 18, 5:12am
I think you're lucky it's copper and probably OK, but only a pressure test will tell you for sure.
lythande1,
Sep 18, 2:36pm
No worries, it can be done.
mrfxit,
Sep 18, 4:01pm
Real easy if you are going for a low pressure mains system (pressure regulator). Had it done once before
atlantis3,
Sep 18, 10:58pm
It is a full mains pressure cylinder that we are putting in and the test pressure is 1500KPA (218 PSI) and he seemed concerned about our old pipe work failing on mains pressure.
johotech,
Sep 18, 11:31pm
That is just the test pressure for the cylinder. Mains water pressure will never be that high.
He should certainly be installing a pressure limiting valve for the whole house if there is high water pressure in your area. Anything over about 800-1000kPa mains pressure would be considered high.
The pressure limiting valves are usually set around 500-700kPa.
In any case, he can pressure test your hot water pipework to make sure that it is ok before he installs the cylinder. The required pressure for testing new pipework is 1500kPa for a minimum of 15 minutes.
The existing cold pipework is already operating at "mains pressure", so there shouldn't be any problem with that.
wembley1,
Sep 19, 12:04am
If your plumber is pulling out copper piping (your header may be copper too) make sure he doesn't perk it. You could cover some of your bill by taking it to the scrap metal merchant.
The old H/W cylinder may have a copper liner too. It's worth salvaging that.
nzjay,
Sep 19, 3:59am
Remember that you may also have to change your shower mixer and some types of mixer taps if you have any, as you will now be going to equal high pressure and your existing shower mixer may be either equal low (if there is a cold feed to the shower off the header tank) or unequal low if the cold feed is mains pressure.
atlantis3,
Sep 19, 5:20am
Thanks everyone. Do we need building consent to change to a mains pressure cylinder as we don't want to jeopardize our insurance or do most people not bother about consent?
johotech,
Sep 19, 5:41am
Not required.
pauldw,
Sep 19, 6:43am
Are you sure of that? OP is going from header tank low pressure to mains pressure not doing a repair with similar equipment.
johotech,
Sep 19, 3:11pm
As shown below, the exemption covers this unless there is a wetback or solar heating connected.
Exemption 38
Replacement or repositioning of water heater that is connected to, or incorporates, controlled heat source. The replacement of any water heater (including the repositioning of an existing water heater) if the replacement water heater is connected to, or incorporates, a controlled heat source or, if connected to or incorporating more than 1 heat source, 2 or more heat sources all of which are controlled.
A controlled heat source has controls or devices that ensure the water temperature in the storage tank is no greater than 90°C.
atlantis3,
Sep 19, 6:25pm
Thanks Johontech but if you look at excemption 37 it says Examples where building consent is required. Replacing an open-vented water storage heater with a valve-vented water storage heater. As the water-storage heaters are not comparable, a building consent will be required.
johotech,
Sep 25, 4:09am
37 only relates to the replacement of any water-storage heater connected to a solid-fuel heater or other supplementary heat exchanger.
As you are reading the "guidance" document, see what exemption 38 states: "Replacing an existing open-vented water storage heater with a valve-vented water storage heater that has a controlled heat source."
Failing that, if you are still a non-believer, I suggest you contact your council instead of a message board.
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