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Safety Testing Pool Heaters

Safety testing heatersIt is worth re-running this old post.

Before coming to you, each heater has journey of testing to come through.

The electronics are made for us in the UK by Cyclops / DJ Assembly in York. The heating coils are made at Backers in Rotherham. They are tested and certified by the manufacturer before coming to us.

Other components are sourced from reputable UK companies such as Honeywell and RS Components.  All have their British Standard mark.

When bringing together the parts, we test each main component individually. Then the assembled unit is further tested.  There are a suite of tests we perform to be able to give them their CE marking.

And finally, we run the heater in water for 8 hours to simulate its use and the check it one last time.

And just to make sure, there is a 12 month warranty period for additional peace of mind.

Also, the ‘4.8kW heater’ and the ‘2.4kW with Control heater’ are both serviceable and will give you a long life.

The rest is over to the customer.  Think of the instructions as part of the product.  The instructions must be read and no one who as not read them should use the heaters.  If you ever lose your instructions, get in touch and we’ll send you some new ones.

Whilst these are relatively low temperature heaters appliances, they still have a hot metal element and should be treated with respect.

We have been making heaters for nearly 30 years, and tested 1000s of them. We know how they work and what breaks them.  Keep to the following and your heater will give you long service.

  • No heater should ever be switched on outside water.
  • No heater should be removed from the water before being switched off, unplugged and allowed to cool
  • Ever!
  • And if any part of the heater has been damaged, do not use it: contact us to arrange repair.






A Little More on PAT Testing Baptistry Water Heaters

We are redesigning the baptistry water heater, so in the New Year, this will only apply to 4.8kW heaters shown here.

With the 4.8kW heater, one element is the master and the other the slave.  Both are independently earthed but the earth on the ‘slave’ flex will not work unless the master is plugged in and switched on.  So, unless you have two PAT testing kits, it is important to get the correct plug.

To get an earth, the usual thing to do would be to touch the heating elements with the earth probe.  The coil manufactuPAT test with earth proberer advises that a contact should be sought at the base of the coil (see the photograph).


The 4.8kW water heater has two plugs and we mark the flex for the master element with a piece of black tape so you get the correct plug.  Then one needs to make a test on both elements (at the base of the element).   Even then, scale on the elements can give a false fail, and I have found that the ‘pencil-like’ earthing probe doesn’t get enough contact.  Most kits come with an alternative ‘dog-tooth’ clamp fitting to go on the end of the earth probe.

To get at the coils, unscrew the 4 corner screws and lift out the top plate (picture 1).  The coils are attached to this and should lift up with it.  Use the clamp to scrape away at the scale and get a better contact.

top view pool heater 4.8kW pool heater passing PAT.

Summary – Use the plug with black tape on flex, and get a good contact on the coil.

Crates for the Pool Heater

Protective crate for baptistry pool  water heatersProtect your pool heater! After a customer sent in their heater for its service in a flimsy cardboard box, and, unsurprisingly, it arrived cracked and bashed, we decided that the heaters need the tough crates for protection.  These are the same lidded crates we use when sending out a heater in hire.  These will keep the heater safe when in storage and in transit.  We’ve put the prices up to cover some of the extra cost.

This applies to the 4.8kW pool heater and the 2.4kW with Control Box.

De-scaling your water heater: 3 different ways


If you are in a hard water area of the country you will find that your heater elements will become coated with limescale during use. As the limescale gets thicker it will take more time and electricity to heat your baptistery. There are 3 ways of tackling this but they differ a little depending on which heater you have.

Chipping it off.

Remove 4 corner screws on the lid and carefully chip away the lime scale from the elements. In most cases this will come away quite easily.


De-scaling using a de-scaler.

Off-the-shelf products such as Killrock (or any other product used for de-scaling kettles). Again remove the 4 corner screws from the heater lid. For the 2.4 heater, slide the lid up the cable out of the way, mix de-scaler using manufacturer’s instructions. Put mixture in a bowl just deep enough to cover the element when heater is stood on its end. Make sure only the element is in the mixture. It will not hurt the plastic box, which will have to be partly immersed too.

For the 4.8 you will need a shallow container with at least one straight side as once you have removed the lower part of the box containing the elements, the elements will have to be immersed without touching any other components. The descaler is mixed as above.

When the limescale touches the mixture it will usually fizz for a while it’s doing its business.

Other remdies use household items such as vinegar.  Whilst you could use an equal part solution of water and household vinegar, you will need a lot of it, as you’ll see.  Mix 1 part vinegar with 1 part water and stand the elements in it for an hour.  Then heat the solution with the heater.  The heater needs to be covered by 10cm of liquid to ensure it is not damaged, so you will have to mix up large amount of vinegar and water.

Only attempt the descaling if you feel confident. If not go to option 3

Return to manufacturer

You could combine service and de-scale as it does not cost a lot and extends the life of the heater.