Category Archives: Mains Pressure

Hot Water Cylinder Trays Are Now Mandatory

IMPORTANT NOTICE: Safe trays are now compulsory with all new internal hot water cylinder installations, as per G12/AS1 clause 5.2.3 of the New Zealand building code.”

The above notice is what you will find on most newly sold (Image of a Rheem) hot water cylinders. Last year one of our blog posts discussed whether or not you need a cylinder tray. At the time the blog discussed a faulty product which resulted in flooding and insurance claim. In that particular instance the damage was minimal and covered by the manufacturer. Can you imagine the yearly claims when thousands of hot water cylinders are installed without hot water cylinder trays?important_notice

You can take a big guess on who would have lobbied the idea and pressed to get this incorporated into recent New Zealand building code G12 amendments. This standard sets a legal guideline on how a hot water cylinder may and may not be installed.

WHO BENEFITS?

Looking across the ditch, our Australian friends have had this requirement (regulation) as part of their compliance documents (e.g standard AS/NZS 3500) since 1996 but for some reason it never made it into the New Zealand building code, until now.

AS/NZS 3500 is also an acceptable standard in NZ which begs the question, why bother with two sets of standards in the first place?

Previously, accidental discharge control was optional unless a potential risk of water damage to another property existed, which in most cases only really applied to multi-story situations. Although control was considered “good practice” the homeowner could “opt out” to achieve savings on the installation. Or the plumber would keep it on the quite “to be competitive” and win a job against more expensive quotes that included the installation of a hot water cylinder tray.

Before the change, manufacturers such as Rheem have stated in installation instructions that a safe tray must be fitted, meaning plumbers should have already been recommending, quoting and installing hot water cylinder trays.

Now that this law has come into effect, ignorance is no longer bliss and benefits are relative to:

> The manufacturer knowing that installers can made responsible for water damage if the standard is not followed.

> The homeowner, knowing that any potential leaks are controlled while they are sleeping.

> The insurance, knowing they can legally peruse compensation on behalf of the homeowner.

Additional benefits also include:

  • Level playing field when plumbers are pricing jobs.
  • Prevention being the best protection.

NOTE: Plumbers and homeowners should ensure the installation complies with the updated standard to avoid any costs associated with non-compliance or resultant damage from water discharging from a hot water cylinder. 

SOME CHALLENGES AND CONSIDERATIONSunderbench_cylinder_on tray

Progress is always accompanied with challenges and challenges are accompanied with questions.

Some legalities are still undefined and It is not clear on whether a cylinder try must be installed on replacement hot water cylinders as well as newly installed hot water cylinders. When a “repair” or “like for like replacement” takes place, the building act allows one to maintain the current state of affairs. For example, although tempering valves are required by law, a plumber does not have to install a new one when replacing an existing old or damaged hot water cylinder that never had a tempering valve to begin with. Its good practice but not a legal requirement. He can just go ahead and maintain the existing setup treating the installation as a “like for like” situation.

But then this principal does not apply to seismic restrains. The DHB is yet to comment on this and we will update the blog once we know more.

Because compliance is relative and no job is like another, you want to be safe and ask the right questions before committing to any installation. Its always best to make an educated decision rather than deal with the unwanted consequences of ignorance.

ALTERNATIVES WHEN IT GETS TO EXPEN$IVE!rheem_27_instant_gas_water_heater

A cylinder tray needs to be connected to an approved point of discharge via a 32mm – 40mm drain. In many cases, for example double story homes the route of this drain becomes a major challenge. Especially when you are talking about cutting walls open or having surface mounted pipework to get the drain out.

If the cost or convenience of having a cylinder tray is not attractive, there are alternatives within the same ballpark in terms of $$$.

 

 

external_hot_water_cylinder

For example Instant water heating. For about the same price of new hot water cylinder + tray you can convert to gas and enjoy the many benefits. We offer LPG and natural gas solutions. Future-proof or expand, your possibilities are limitless.

Alternatively…

Relocate your hot water cylinder to the outside and free up that cupboard space. In external situations, no cylinder tray is required and the costs are about the same as a new internal hot water cylinder + tray.

Most of our customers tend to go for this option when the installation of a cylinder tray becomes too difficult or expensive. Talk to us for more information.

AMENDMENTS IN G12, 

Lets have a look at G12 a bit closer.

You can view the old and newer version (third edition) of G12 by following this link VIEW G12 AMENDMENTS.

Its very interesting to see that they have removed the wording from 6.11.3

a) Safe trays complying with Paragraph 5.2.3 where water could penetrate another household unit within the same building.

Which now reads:

6.11.3 Storage water heaters shall have: a) Safe trays complying with Paragraph 5.2.3

tray insallation

The above relevant paragraphs read as follows:

5.2.3 now reads..

Safe trays Performance E3.3.2: states that; Free water from accidental overflow from sanitary fixtures or sanitary appliances must be disposed of in a way that avoids loss of amenity or damage to household units or other property. An acceptable method of preventing water damage is to locate a safe tray below the water tank (see Figure 4). The safe tray shall incorporate a drain with a minimum diameter of 40 mm. Where the tank overflow discharges into the safe tray, the diameter of the safe tray drain shall be greater than the overflow pipe from the tank and comply with Paragraph 5.2.2.

RELATED PARAGRAPHS

5.2.2 Overflow pipes Water tanks shall have an overflow pipe to discharge any overflow to a visible place within the same property that does not create a nuisance or damage to building elements. The overflow pipe shall be sized so that the discharge capacity is no less than the maximum inlet flow. The outlet of the overflow pipe shall not permit the entry of birds or vermin. Overflow from a WC cistern may discharge internally into a WC pan.

COMMENT: Manufacturers’ literature must be referenced for pressure and flow information on tempering valves and tapware. Outlets (e.g. shower mixers and showerheads) must be appropriate for the available flow and pressure. Note the limitations on lengths and pipe sizes given

6.11 Water heater installation

6.11.1 Water heaters shall be installed in accordance with the manufacturer’s instructions.

6.11.2 Where heating units, sacrificial anodes, thermostats, pipework connections, valves, or other accessories being components of a storage water heater are installed, they shall be accessible for inspection, maintenance and removal.

6.11.3 Storage water heaters shall have: a) Safe trays complying with Paragraph 5.2.3 b) Connections compatible with the pipe material used, and c) Drain pipes (for every storage water heater of more than 45 litres capacity) which: i) have a conveniently located isolating valve, and terminate with a cap or plug suitably located to easily empty the vessel for maintenance, or ii) terminate outside the building with a cap only.
cyl;inder setup

The installation below shows the safety valves discharging into the cylinder plug and waste, which does not comply as one could argue that these pipes are blocking the passageway designed for the control of accidental water which is managed by the safe tray only. NZ Regulations define acceptable methods of discharge which includes safety valve drains.

cylinder_drains_into_tray

 

 

How many hot water cylinder types is there?

Have you ever wondered about how many types of hot water cylinders there actually is?

We have complied a list of hot water cylinders for you, showing application, benefit and disadvantages helping you make an educated decision before purchasing your next hot water cylinder.

First of all we need to separate the PRESSURE TYPES from the MATERIAL TYPES. In New Zealand one can purchase almost any material type at three different pressures.

Most common pressure types available in New Zealand (Domestic Applications) 

    • Low Pressure, open vented systems where the pressure is provided by a cold water storage tank, open vent or rely on a pressure-reducing valve to reduce the pressure below mains pressure supply.
      Typical Pressure: 30 – 75 KPA, typically 3 – 7.5 metrets Head
    • Medium Pressure, open vented systems where the pressure is provided by a cold water storage tank, open vent or rely on a pressure-reducing valve to reduce the pressure below mains pressure supply.
      Typical Pressure: 75 – 120 KPA typically 7.5 – 12 meters Head
  • Mains Pressure, with a working pressure equal to incoming supply. Pressure can be limited to any requirement but using the appropriate valve work.
    Typical Pressure: Ranging from 120 – 1400 KPA (Domestic Supply is typically 350 – 750 KPA depending on requirement)

Mains pressure water heaters are the predominant type of new installation in Australia and New Zealand.

COMPARISON TABLE OF HOT WATER STORAGE TYPES AT DIFFERING PRESSURES. 

hot_water_cylinders_types

The following hot water cylinder material types are available in New Zealand

   CYLINDER MATERIAL PRESSURE ADVANTAGES DISADVANTAGES
Enamel Lined Low Pressure
Mains Pressure
– Supply of mains pressure
– Low cost supply Installation
– Very common in NZ
Requires sacrificial anode
8 – 20 year life expectancy
Copper Low Pressure
Medium Pressure
15 – 40 year life expectancy
– Large Storage at low cost
– Can be used for high temperature power
sources such as wetbacks and solar.
 

– Not suitable for most  modern tap ware
– Requires sacrificial anode
– Low pressure

Stainless Steel Low Pressure
Mains Pressure
– 15 – 50 year life expectancy
No sacrificial anode required
– Can be used for high temperature power
sources such as wetbacks and solar.
– Large storage at high cost
– Higher supply cost
– Come with the longest warranties

Continuous flow hot water systems prices

With gas prices down, its time to upgrade to a continuous flow hot water heater!

To make it even more compelling we are now offering a fixed system price to upgrade from electric storage to continuous flow LPG or natural gas with everything included.

CURRENT GAS HOT WATER CONTINUOUS FLOW SYSTEM PRICING FOR NG AND LPG GAS

continuous_water_heating_natural_gas$2,800.00 incl. GST and installation natural gas

This installation includes everything you need to convert from your current hot water storage to continuous flow hot water.

We will supply and install a Rheem 27 continuous flow appliance in an approved location and certify the installation as required. This includes a connection to an existing natural gas meter. Whether you currently have low or mains pressure this is full supply and install price which includes everything you need to get into that endless hot shower you have been craving!

 

 

continuous_flow_hot_water_systems$3,049.00 incl. GST and installation LPG

Similar to the above, this installation is designed to accommodate a LPG installation when natural gas supply is not possible/available or too expensive.

Available with a 27 Bosch or Rheem continuous flow heater. All connections and supply of pavers also included

lpg_bottlesTo make this deal even more attractive, we will throw in 1 free bottle of LPG at a value of $150!

The installation includes all required components required to replace your existing low or mains pressure hot water cylinder. Commonly a site visit is required to ensure that placement complies with the relevant standards and safety requirements.

Ongoing gas pricing may vary but is currently trending at $80-$120 per bottle depending on your supplier. If in doubt, please ask our team about current rates prior to ordering.

 

 

Rheem_continuous_flowAll continuous flow hot water heaters included in the above deals require an electrical connection for ignition (we also offer self igniting hydro powered continuous flow heaters on request). We can offer the electrical connection at a fixed price of $350 + GST. Alternatively you are free to organise an electrician of your choice to be onsite on the day of the installation.

All installations are installed by qualified gasfitters and plumbers and come with a full Master Plumbers warranty.

We WONT be beaten on price so make sure you are quoted apples for apples. In any case claim your $50 if you do!

Upgrading your sacrificial anode when replacing a hot water cylinder.

hot_water_cylinder_anodeHow would you like to increase the life span of your current or new hot water cylinder by at least 10 years?

Sounds too good to be true? Every hot water cylinder contains a sacrificial anode which prevents the breaking down of the tank and components. As the name suggests “sacrificial” would mean that at some point it would have to be replaced to maintain this form of protection. In the image to the right you can clearly see the difference within 10 years of operation. Most house holders are not made aware of this fact and unknowingly allow the continuation and breakdown of their relatively young or new hot water cylinder.  By replacing this sacrificial rode you can easily add another 10 years to its operation saving significant cash by preventing the breakdown of metals.

The sacrificial anode (also called an anti-corrosion rod) is typically made of magnesium. It it used to attract corrosive elements so that the tank itself will not corrode as quickly. It can be replaced when it is badly corroded.

But when your hot water cylinder is installed in a tight spot with limited height which is the case in most scenarios, how can you replace this rode (typically over 1 meter length) without actually removing / disconnecting (which would cost you more than its worth) the hot water cylinder to fit it in?

Making it easy to change a cylinder anode when clearance is tight.

When is time to replace your sacrificial anodes you might be faced with several challenges. Either HWC_Anodeyou will have to drain and remove the hot water cylinders or you may have to put a hole through the ceiling above for access. So what is the solution? A flexible Anode! this specialized anode requires less than 250mm clearance and can be installed within 1 hour. So whether you have an exiting cylinder or getting a new one, why not ask to be upgraded to one of these allowing you to make the replacement when its due? Saving you cash long term!

Please ask our team about this upgrade which can be purchased for under $200 with a new installation.

 

 

 

HUNSON RT AKA “THE ELEPHANT”

Hunson_brandManufactured in Glen Innes Auckland on January 1978 by W. Hunt & Son Ltd this HUNSON RT revolutionized mains pressure water heating in New Zealand!

Due to high manufacturing costs and technology limitations, in the 1970’s hot water cylinders were primarily manufactured from copper.                                                         hunson_RT

Copper hot cylinders are made to suit low to medium pressures (75KPA – 120KPA), with medium pressure cylinders being made from thicker copper. The week spot on a cylinder is not the actual copper material but rather the machine manufactured welding seams. Anything above 120KPA depending on weld quality and the seam will crack resulting in a burst hot water cylinder!

So how do you get around this problem and achieve mains pressure using low pressure technology? W. Hunt & Son Ltd certainly acknowledged the demand for mains pressure and their reply was the advanced Hunson RT Direct mains pressure hot water system. Great engineering and ahead of its time.

What makes the Hunson RT so special?

hunson_diagram

 

The basic principal was to use the heat exchanger to supply mains pressure ONLY to one shower making it a semi “instantaneous water heater” (in the 70’s showers started becoming more popular) whilst using the large low pressure body of water to supply the exchange heat to the mains pressure coil and direct supply to all other low pressure fixtures such as a bath or laundry.

On request Hunson could manufacture these cylinders with multiple elements up to a total of 8KW! This would certainly make the supply more reliable and showers longer but expensive to run (not sure about power rates VS income in the 70’s). Modern cylinders use the same technology in reverse because water can now be stored in a mains pressure environment (stainless steel or enamel) and of course also because of a few other reasons such as efficiency and reliability.

What challenges did this “new style” mains pressure cylinder present to home owners?

hunson_rt_instructions

 

 

To start with, it was important the plumber got the installation right. If you have a look at the image you will see the instruction says: “At all times, the flow from the cylinder should be strong and steady, but not excessive”. Mains pressure can be anywhere from 120KPA to 500KPA and the term “not excessive” is too broad. If the pressure was set too high the heat exchanger would not have enough time to keep up with the demand. Plumbers also started using the mains pressure supply (which was originally only intended for one shower) to deliver mains pressure to the whole house and all plumbing fixtures! This immediately presented a problem because the standard supplied element of 3KW could not keep up with the demand and showering usually was over after 5 minutes! This was also the case with Hunson RT you see in this image. the only reason this cylinder survived over 30 years was because the hot water from the low pressure supply side was never used. The sludge build-up on the inside would reach all the way up to the element. Despite a sludge relief point which was most likely never ever used.

Another common issue this technology presented was random cold patches during a warm shower. Have a look at the diagram and see whether you can identify expansion, cold water inlet, hot water supply, overflow and sludge outlet. This date_230178cylinder also provides bottom entry connections for wetbacks.

Why did this hot water cylinder receive the nickname “The Elephant”? 

It turns out there used to be an engineering company in New Zealand call Elephant NZ. Elephant NZ originally came with this technology and design which was purchased by W. Hunt & Son Ltd. Why that actually engineering company was called Elephant, we don’t know but if you do, please send me an email so we can add this info to our article.

Under-bench Hot water cylinder struggles for space

underbench_hot_water_cylinderTalk about limited space! When we arrived onsite we immediately knew we would be challenged with this exceptional under-bench hot water cylinder. Existing cylinder tank is 45 Liters and needs to be replaced (burst) with an equivalent size. The problem though is that the new Rheem hot water cylinder is much wider at 535mm in diameter. This is mainly due to the fact that newer hot water cylinders are now manufactured with more insulation making them “fatter”. after Disassembling and relocating all plumbing to the left hand side of the sink bench we gained further 150mm which made it possible to fit the new under bench cylinder and ensure all valves trains and wastes are installed as required by NZS 3500. What initially seemed impossible worked out to be a 4.5 hour installation with a very pleased client! Another successful job for hotwatercylinders.nz!

HJ Coopers installed in under 3 hours

HJ Coopers tight fit WHAT A TIGHT FIT… In and out in 3 hours! The call came in at 9:30AM with Mrs James advising that her old low pressure Rheem which is over 30 years old has burst! Considered about timing because her holiday was already booked for the following day hot water cylinders NZ made it happen! To get this job done we have to not only “squeeze” the actual job into the day but also had to SQUEEZE the HWC into the cupboard! After we detached the panel, we managed to get the Gib out of the way and rearrange the timber to make the new mains pressure tank fit. Luckily it was easy enough to run a drain and the tempering valve rated to be screwed straight into the tank making a what seemed to be a hard installation very easy! In just under 3 hours this installation was done for our stainless special rate! Stainless Steel mains pressure solar ready with 20 years warranty, now Mrs James can go on holiday without having to worry about her hot water when she gets back! If you have a situation where you believe a new tank might not fit, let us know and we will do an obligation free site visit to advise on what solution works best for you! Call us 0800 4 Cylinders

15 year old burst Rheem mains pressure cylinder

old-rheem-hot-water-cylinder

15 Year old burst Rheem hot water cylinder

15 Year old Rheem hot water cylinder

Its always frustrating when your hot water cylinder fails just after the warranty expires 🙁 Its rare but it happens, even to a Rheem! In most cases the problem relates back to the quality of water. Unless your hot water cylinder is made of stainless steal it will most likely incorporate a sacrificial anode. If you are on tank or bore water supply and have a mains pressure cylinder, you should regularly (every 2-5 years) have a service done. By servicing your hot water cylinder you can avoid a nasty leak in future caused by corrosion. In this instance we were able to offer our special like for like mains pressure hot water cylinder replacement for $ 1200 all including! Concerned your cylinder is suffering from corrosion? Better safe then sorry 🙂