Category: Hot Water Talk

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Blowing up a hot water cylinder

I made this GIF from an experiment done by Myth Busters to show the extent of damage a hot water cylinder can do when there is no pressure relief. blowing-up-hwc

The image above reinforces the importance of using individuals that understand the physics of hot water and the effects an installation can have on its surroundings.

So at what point will a cylinder explode?

In principal it’s simple to understand. Heating a substance causes molecules to speed up and spread slightly further apart, occupying a larger volume that results in a decrease in density. So “larger volume” means “more space” which is limited to the size of the hot water cylinder.

If hot water is not used and your thermostat fails, your immersion element will continue heating your water (to boiling point) until such time one of the pressure relief valves activates and relieves the pressure. Every installation should include two relief valves, one on the cold water side and one on the hot water side.

This regulation was put in place around 1997 meaning that any cylinders installed prior to that may only have one source of pressure relief. Hence the low pressure vent copper pipe going through the roof.

This is where it gets tricky. Many installers dont bother replacing older valves when replacing an old hot water cylinder with a new one. Others have managed to install a tempering valve on a low pressure system right into the overflow pipe, blocking the only means of pressure relief. The hot water system then becomes a time bomb which may result in something pictured above.

Sometimes its not the plumbers’ fault but rather the homeowner who sees a pipe dripping on the outside of a house and thinks.. “Oh, this should not be leaking” and decides to “blank” it off by any means available, creating the perfect conditions for a catastrophe. My recommendation on this is, see a dripping pipe? Please call the plumber.

If you are unsure about what valves you need or already have, send us an email or give us a call for help.

 

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10 Mistakes to avoid when buying a new Hot Water Cylinder

  1. Price Price Price
    Compare the price you have for one brand with another quality brand. Don’t be shy to ask for an alternate brand quote. Look at the differences and select the product that will most likely meet all your expectations now and in the future. This will also filter out those who are ‘partial to one brand’. They will always give you reasons as to why ‘their’ brand is better than the others.10_Mistakes_to_avoid_when_buying_a_new_Hot_Water_Cylinder
  2. Don’t Settle for Less.
    If you have to replace your existing hot water cylinder, make sure you get the most recent technology and quality. Many installers will try to flog off outdated stock and make it look like the deal of a lifetime. You will be surprised what modern specifications you are able to get for the same price without having to compromise on quality or warranty.
  3. Low VS Mains Pressure
    Let’s face it, with today’s technology, the world is going mains pressure. If you are replacing your low pressure cylinder, don’t let anyone tell you that you can’t replace it with a mains, because you have low pressure tapware. You can in fact upgrade to mains pressure and set your mains pressure system to accommodate your low pressure tapware. That way you have already future proofed for your upcoming new and amazing mains pressure tapware.
  4. Future Proofing
    This ties in nicely with point #1. Believe it or not a cylinder that is future proofed for solar, heat pumps and alternative energy will cost you the same as a cylinder that is not. With climate change and the costs of energy on the rise, you want to be ready for the next energy revolution which will involve having a cylinder that is also ready.
  5. Warranty
    Read the fine print! They say you get a 20 year warranty when in fact it’s conditional to a yearly service and expense, this should not be required at all, especially in the first 5 years. Seven to 10 years is a good indication of where a warranty needs to be here in New Zealand. Please note that parts subject to wear and tear are in most cases only covered by a one year warranty.
  6. Power Supply
    The trouble with cheap quotes is that they tend to leave out what They believe ‘you don’t need’ but will in-fact only benefit you in the long run. For example, this is the case with the power supply to your new hot water cylinder. If you are replacing an older hot water cylinder, your power switch will be of the same age and wont comply. If it’s round and in most cases black (Baker Light Power Switch), it must be replaced. These switches are deemed as unsafe (electrical hazard) by the electrical board of New Zealand because they can only support 10 AMPS (just below 2KW) and most cylinders now require 16 AMPS the same goes for the wiring from and to your hot water cylinder and electrical board. The last thing you want is for an older component to cause damage to your new shiny hot water cylinder or home and voiding the warranty in the process.
  7. Compliant Installation And Certification
    No one expects you to be a plumber but it is always good to know a bit more about your installation. Do the research and find out what the minimum requirements are. The best place to start is by looking at the New Zealand Building Code G12 which can be downloaded for free >> G12. It will only take 15 minutes to get your head around the basics. You will then be able to ask the right questions and the installer will be very careful not to cut any corners. Make sure your installation complies and that you have received a producer statement on completion. This will be very important when you come to sell the property as it becomes part of your LIM report.
  8. Maximise The Size Of Your Storage
    if you have the space, USE IT. The more water you can store the more efficient you become. They all come with 2KW or 3KW elements so you are not ‘using more energy’ you are only heating more water that is stored and ready to be used. The insulation values are the same so minimal heat loss. Considering point #4, another advantage is, should you decide to add an alternative cheaper form of energy later, you will be able to store more water that has been heated efficiently. Because most forms of alternative efficient energy are dependent on having sunlight or the right temperatures, you want to heat as much water as possible during that time and use your storage outside that time. Hence it’s best to store as much hot water as possible. As a small example, the price difference from going from a 180 Litre to a 300 Litre hot water cylinder is about $300.
  9. Licensed Installers
    We cannot voice the importance of this enough. Make sure the installer is registered! Regardless of whether the installation complies or not, the technician must be licensed and registered by the plumbing board of New Zealand. If not and something happens, your insurance will bail. ASK TO SEE THE LICENSE and on completion ask for a producer statement. Selecting an installer that is a Master Plumber will ensure you have someone that is experienced and insured to do the job.
  10. Drain Discharge Size And Location
    Some guys just looooove cutting corners and the discharge pipe is the most likely place. It takes more materials and more time to run the drain to an approved and less annoying position. On most installations, the drain must be 20mm to comply (refer to G12 above). All pressure relief valves from your hot water cylinder discharge water every now and then. This happens as water is heated and expansion takes place. The last thing you want is for a pipe to be sticking out your front door or constantly discharging water onto your footpath. All drains must discharge into an approved point of discharge. What is considered an approved point of discharge? Give us a ring to find out or stay tuned for my next blog.
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Christchurch shake affects hot water cylinder manufacturers.

4.3 magnitude earthquake in Christchurch shakes residence and hot water cylinder manufactures!

christchurch_earth_quake_damage_hwc

Yet another earthquake hits Christchurch and like every other earthquake this one leaves frustration and damage in the millions behind. Peter Cocks have been manufacturing hot water cylinders in New Zealand for decades and despite being prepared for the constant “shakes” every now and then, over 100 hot water cylinder got damaged in the quake.

This of course affects distribution throughout New Zealand, especially Auckland being the largest hot water consumer.

Peter Cocks have been recently sold to Rheem so the timing could have not been any worse/better? I suppose this will fully depend on who is looking at it 🙂

If you live in Christchurch and you are getting your hot water cylinder replaced, ensure your seismic restraint is installed correctly. This could save lives and definitely save you money even in the smallest quake. Hot water cylinders LTD have been busy helping Christchurch residence get their hot water cylinders repaired or replaced. If you are affected by the recent quakes give us a ring for immediate assistance.

We look forward to hearing more about Peter Cocks’ new venture with Rheem and will certainly keep you posted on any product advancements and updates. If you currently own a Peter Cocks hot water cylinder and are concerned about any future warranty related claims, dont be. Peter Cocks have already issued a statement guaranteeing the continuation of all warranties through the new purchaser Rheem. Peter Cocks may continue to operate under the current brand name “Peter Cocks” but only time will tell.