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?

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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?

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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.

Internal natural gas hot water cylinders

Iinternal_gas_hwcinternal gas hot water cylinders are always a bit harder to replace because of existing installation conditions. Gas hot water cylinders installed 10 + years ago may not comply to the latest standards. this includes ventilation, flue penetrations, floor base, seismic restraint and several other factors. New products such as the internal Rheem 170L are much more efficient and carry 5 year warranty. What do our installers look for before installing one these models?

  • Ensure the platform is fire resistant (e.g. concrete paver will do it)
  • Ensure there will be sufficient ventilation at lower level and down draft diverter to allow for complete and safe combustion.
  • Check to make sure the existing gas supply pipe is of sufficient size.

    On completion our technicians are required to do a full gas pressure inspection to confirm there are no existing or new gas leaks. Once the installation is complete seismic restraints will attached to secure your new hot water cylinder and finally a gas certificate can be issued that your new hot water cylinder is deemed safe and sound. Hot water cylinder NZ offer various gas hot water solution’s including instant water heating and combination central heating. For more information please call us on 0800 4 Cylinders.

What are Calorifiers?

A calorifier is a heat exchanger which heats water indirectly by circulating is over a heating coil or multiple coils. The source of heat can be water or steam, heated by an external heat source, contained within a pipe immersed in the water. the two bodies of water or steam do not mix. (touch each other)

In hospitals and factories where steam is already being generated for other uses is can also be used to heat the water by the indirect method.

The calorifier may be a continuous coil of pipe or a cylinder within a cylinder with an annular space between the two vessels.

calorifier_design

With the vertical hot water cylinder, the steam enters the coil though the top connection. the strainer or grit trap removes any solid matter suspended in the steam. The steam then passes through the inlet valve which is thermostatically controlled. the thermostat prevents overheating or boiling of the stored water.

A steam trap, fitted near the outlet of the coil, prevents the steam from leaving the coil until is condenses.

In a hot water cylinder which contains a steam coil, the coil must be able to be removed for descaling. this is more likely to occur using steam because the coil is working at a higher temperature than with the conventional hot water system.

Hot water cylinders Ltd provide custom hot water cylinder (storage tanks) design and construction with integrated calorifiers at most demanded KW sizes. Our services include domestic and commercial applications. With water applications heat sources such as Heatpumps, Gas, Solar or steam can be applied. For more information please contact us on 0800 4 CYLINDERS.

Heatpump hot water cylinder conversion

heat_pump_hpt_water_cylinderIf your looking at saving power ($$$) with your domestic hot water heating demand, your hot water cylinder is leaking or you are keen on upgrading to mains pressure why not consider a heat pump hot water cylinder?

Save up to a third on your hot water bill with this Aquarian Heatpump! These heatpump cylinders can be installed internally as well as externally with the difference that the air intake must be ducted to the outside if the installation is to take place inside. This is usually achieved by ducting directly up through your existing hot water cylinder cupboard and out through the roof. Our installation special includes a flashing fro your roof, all ducting (up to 5 meters), all involved labor and materials for $ 4999 including GST . If your a high hot water user or want a quick return on your investment now is the time to place your order! For more technical info on this heat pump hot water cylinder please CLICK HERE

Please note that electrical services are not included and an obligation free site visit must be made by us prior to our commitment.

For alternative heat pump specials please visit our heat pump catagory section.

Over 30 years! Starkie HWC supplied by Henry & Co LTD

henry_and_co_ltd_hot_water_cylinder

Every now and then we come across goodies like this! This hot water cylinder has been supplying hot water for over 30 years! Originally supplied by Henry & co Ltd. A quick Google search reveled the company is still around as a tool supplier. The bottom clearly show the state the cylinder is in, we are confident the cylinder rusted through years ago but its own weight created a natural seal preventing water to lea out. Eventually the holes got bigger and bigger leading to what it is today. I would love to know how many showers this tank accommodated!

What a great find..rusty_low_pressure_water_cylinder.

Gas Water Heating on LPG

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Another successful LPG installation onto a Rheem 27 instantaneous hot water heater. The purple bin which is holding up a 9KP LPG cant be missed and is currently only a temporary solution to test the system until the 45KG bottles arrive which will be standing on a concrete base as per the gas standard.

In this artcle I wish to discuss the commissioning of LPG cylinder systems.

The commissioning of LPG cylinders must meet the same requirments of NZS 5601. However, special methods and precautions are required due to the special characteristics of LPG and its equipment.

The special requirements of LPG installation commissioning relate, for example to the relative density of LPG and its storage as liquid. Special purging methods must be used for LPG and sufficient ambient heat to boil the liquid gas.

Special LPG equipment includes fixed and mobile installations including single cylinder, twin packs, or cylinder banks. Systems may have auto-changeover regulators, which may include automatic ordering features.

NZS 5601 includes references to commissioning gas installations which requires every part of a gas installation to be commissioned and certified.

If you are getting quotes for gas water heating its important to make sure the installers are registered gasfitters. Even qualified trades people make mistakes so also very important to check with the installer that all commissioning requirements have been met.

Hot water cylinders LTD have several gas water heating specials which includes supply and installation. For more details please call us on 0800 429 546 or email gas@hotwatercylinders.nz

Ruud Hot water cylinders (Ruudglas Pacemaker DV)

Ruud_hot_water_cylindersIn this picture you can see two old gas powered Ruud hot water cylinders. The flues have been installed without a down draft diverted using a powered flue to remove products of combustion. These  cylinders have lasted 10 years and its amazing to see that both show the same signs degradation. The most challenging part of this job is that the cylinders have been installed in the worse place possible. Down three sets of stairs in a lower level that is over 300 meters away from vehicle access. It will be a logistical challenge! The job description is to remove the two gas powered cylinder and replace with one storage tank which will include a heat exchanger powered by a system 24KW system boiler. The storage tank will allow us to maintain the existing plumbing arrangement which also includes a ring main. The new system will be saving on operating and maintenance costs straight away! The old powered flue can also be removed as the new unit comes with a compact flue arrangement that can routed as required. This area if fully ventilated hence all building and code requirements can be met. With more sophisticated jobs such a this planning is paramount. Experienced installers can save you money and hassle! If you are looking at replacing your old gas hot water cylinder with an instant water heater, please view our instant water heater specials here.

Its been a busy week for hot water cylinders!

many_hot_water_cylinders

2015 has just started and we are already in full gear!

All these leaky hot water cylinders can now only be disposed of as scrap metal. The mixture is never the same. Sometimes we have more mains pressure cylinders and sometimes only low pressure. A few months ago we even replaced 8 external gas Vulcan Freeloaders in 3 weeks! Its funny how the trend goes and very interesting to watch such anomalies.

Hot water cylinders LTD has many upcoming specials in 2015.  Some of these include:

  • Mains Pressure conversions
  • Instant gas hot water conversions. (gas water heating)
  • Stainless Steel upgrades.
  • Relocating internal hot water cylinders externally.
  • Complete services and maintenance programs.

To get your obligation free quote on replacing or repairing your hot water cylinder, please call us on 0800 429 546 or email quotes@hotwatercylinders.nz

No Hot Water on New Years :(

no_hot_water_testingThe last thing you need when you come back from holiday is to find your hot water cylinder has stopped working especially when you urgently just want to take a shower! Many people tend to turn their hot water cylinders off during this time. This in itself is not a problem unless your hot water cylinder is 10+ years old. Turning off the power to your hot water cylinder will of course allow the body of water inside the tank to COOL OFF, this is something your hot water cylinder is not used too as water is constantly maintained at 60 degrees. This “cooling off” will result in extreme contraction of the tank itself which initially does not cause the leak. Most Aucklander’s will coming back from holiday and the first thing they do is switch on the power to the hot water cylinder which will immediately power-up a 3KW element which in return will heat up the body of water back to 60 degrees in a relatively short mount of time. This will now cause the tank to expand very quickly. Depending on age this is when your hot water cylinder might spring a leak! Unfortunately we cannot give you advice whether to keep the power on or off during your absence but encourage you get your hot water cylinder serviced prior to going on holiday to ensure you don’t come back to any nasty surprises. In the image above the home owner was very fortunate that only the immersion heating element was damaged. Replacement of the element was under $200 and included a full check of the thermostat and hot water heating system.

30 year old Simplex hot water cylinder

simplex_hot_water_cylindersIt’s amazing how many of these Simplex hot water cylinders we come across in the Auckland area. This year we ripped out more than 100 Simplex hot water cylinders! In most cases the hot water system was converted to a main pressure system which required an installation of an additional drain and mains pressure valves. In this picture you can clearly see that only means of safety available is the open vent which deals with any expansion (sometimes caused by over heating). There is no tempering valve, no expansion valve and no drip try. Its amazing that these copper cylinders can last up to 35 years without bursting. Usually the only reason they do end up bursting or rusting away is because the thermostat fails which results in the element overheating the water to 99 degrees and this puts more stress onto the tank resulting high level expansion and contraction cracking the weld. Quality of water is also a big contributor to rust and life expectancy of a copper hot water cylinder.

Has your cylinder burst before the recommended expectancy? Maybe its a good idea to investigate the cause before installing your new one to ensure your new hot water cylinder lasts much longer.