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How to fix a common Pulsacoil fault yourself

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Replacing a Gledhill Pulsacoil 2000

When does a Pulsacoil 2000 actually need replacing? 

The main reason for replacing a Pulsacoil (of any variety) is a leak from the internal copper tank. The Pulsacoil 2000 and Pulsacoil A-Class seem particularly prone to the internal tank leaking. All other faults on a Pulsacoil can be repaired. 

A leaking internal tank cannot economically be repaired as it is contained within the outer steel case which is impractical to dismantle. This however leads to the second reason for replacement - owners becoming exasperated with the sheer unreliability of certain Pulsacoil models and deciding to cut their losses and fit something better.

Not all leaking Pulsacoils need to be replaced. They commonly leak from the heater elements, which can be replaced to fix the leak. It’s only when the copper tank inside leaks that they need replacing. 

Here are a few photos of a typical Pulsacoil 2000 with a leaking internal tank. Note in particular the rusty areas at the very base and the rust streaks down from the little holes in the outer steel case. If yours has these marks then yes, it is leaking from inside. 

The leak from inside means you’ll need to top up the plastic header tank on top periodically (to replace the leaked water) in order to keep it working, and cope with the dampness in the floor created by the leak. If you can cope with these two things then there is no particular hurry to replace it quickly, or to replace it at all! I get a small trickle of enquiries from people who have been frightened by scaremongering plumbers into believing their Pulsacoil which is leaking so slowly they didn’t even notice, needs replacing urgently. There is no risk of a tiny leak suddenly turning into a flood. The leak may get progressively worse but this takes months or years so don’t allow yourself to be pressured into a hasty decision. 

There is a completely different failure that happens on on a Pulsacoil BP that requires urgent replacement of the whole appliance. This is where the header tank on top fills up unexpectedly, over-filling and overflowing into the flat or apartment. The user bales out the tank to lower the level but the level continues to rise and overflow. The only way to stop this flooding is to find and turn OFF the incoming mains stop-cock. The cause is a crack or split in the coil of pipe inside the main tank of a Pulsacoil BP. The only solution is to fit a new thermal store.

Here are few FAQs that regularly crop up in conversation with Pulsacoil owners considering a replacement…

Why is such a complicated  and unreliable device fitted in my flat, and can I fit an ordinary simple hot water cylinder instead?

Pulsacoils are fitted in modern flats instead of conventional copper cylinder as seen in two storey houses, because those low pressure copper cylinders will not supply adequate water pressure to feed a shower when fitted in a single storey flat, due to the lack of adequate water head. A Pulsacoil delivers high pressure hot water so the showers work properly. So, as your flat probably has a shower, you can't replace it with a conventional low pressure copper hot water cylinder.

What can I replace my Pulsacoil with? Do I have to have another thermal store?

There is an alternative type of hot water system called a 'mains pressure unvented hot water cylinder' (commonly referred to in the trade as a 'megaflow*) which also delivers high pressure hot water. These suffer from none of the faults of a Pulsacoil, but, as you may have guessed, come with a whole different set of problems. These have to be fitted with a large diameter copper safety discharge pipe running downhill all the way to outside. Most Pulsacoils are fitted in an airing cupboard in the centre of the flat so a megaflow* is ruled out.

Ok, so do I have to have another Gledhill? Are there any other make a bit more reliable? Or a LOT more reliable?

No, yes and yes, in that order :) Other than the Pulsacoil original, all the earlier Pulsacoils were unnecessarily complicated in my opinion, and all seem to suffer from repeated breakdowns. Gledhill appear to have learned not to over-complicate things and now produce the Pulsacoil ECO STAINLESS, which has fewer parts to fail and more reliable electronics. The other firm I suggest is Advance Appliances Ltd who make a very simple format electric thermal store topographically identical to the Pulsacoil original, and consequently far more reliable than the Pulsacoil III, 2000 and A-Class, and costs less than a Pulsacoil ECO STAINLESS. 

Which manufacturer then?

There are three stainless-steel-tanked thermal stores on the market now that I am aware of. Here are the links:

The ETS160 Electric Thermal Store by  Advance Appliances Ltd

The 'Coral Aquanox Direct' by Elson Hot Water 

The 'Pulsacoil ECO STAINLESS' by Gledhill 

Which one do I recommend?

I have recently been recommending the ETS 160 by Advance Appliances, but each has its advantages and drawbacks.

The ETS160 is nice in appearance and has a big price advantage over the its competitors. The header tank is neatly incorporated into the unit unlike the Pulsacoil, and there is a sight gauge and temperature gauge on the front so you can check at a glance the unit is properly full of water and up to temperature. The drawbacks of the ETS 160 are that it comes in only one (smallish) size, 160 litres, so it is not suitable as a replacement for the larger Pulsacoils unless you are happy with a reduced hot water capacity. The external pipework and expansion vessel are non secured to the unit prone to damage both during installation and in general use - easily knocked by ironing boards etc stored in the airing cupboard causing leaks. The unit has an internal passive tubular heat exchanger which is simple with no electronics or pumps necessary, its terribly susceptible to water scale so scale treatment of the water is essential.  

I have no experience of the Coral Aquanox Direct so cannot really comment on it other than to say the brochure shows it comes in a range of sizes so would be a good replacement for a larger Pulsacoil. Neat in appearance with header tank incorporated but customers tend to reject it in favour of the advanced Appliances ETS160 because seems to be about twice the price.

The new 'Pulsacoil ECO STAINLESS' has been introduced by Gledhill to address the main reason an older Pulsacoil needs replacing, pin-hole leaking of the interior tank. Copper shouldn't do this but it does, and all older Pulsacoils have sheet copper interior tanks which seem to leak as the unit grows older, forcing the user to replace it. This new model has a tank made from stainless steel which doesn't suffer from pin-holing... Supposedly... but time will tell :) The heat exchanger is external with a pump and electronics to control it so less prone (but not totally immune from) water scaling. The header tank is separately installed from the main unit so installation costs are a little higher. The unit price falls neatly neatly between the prices of the other two options listed above. Selecting the right Pulsacoil STAINLESS to replace a Pulscoil 2000 can be a bit of a headache so I've made some notes here.

The Fabdec ThermaCoil. (Edit: Since writing this page, this unit has been withdrawn from the market. I’m leaving this paragraph here for info only.) This is the most recent entrant to the market place, being marketed and sold by “The Plumbing Group”. Its a neat and tidy looking appliance and appears to be topographically the same as the Pulsacoil Original, so having an internal heat exchanger will probably suffer the same scaling problems. Descaling an internal heat exchanger is a messy, noisy and time-consuming process involving pumping acid descaling chemical through the scaled heat exchanger for several hours. For this reason I don’t recommend installing any appliance with an internal heat exchanger in a hard water area. Scaling problems were the reason the Pulsacoil Original was discontinued and replaced with the Pulsacoil III with an external and quickly replaceable heat exchanger. The main reason for building an appliance with an internal heat exchanger is economy. They are so much cheaper to make! 

Can I fit a replacement for a Pulsacoil?

I am not an installer these days, I specialise in fault tracing and repair. I generally decline requests to install equipment, but in the case of a Pulsacoil I make an exception provided you are reasonably close to me and it is not the busy season for my main business of boiler repairs i.e. winter. This is because although installation is generally quite straightforward, customers seem to have great difficulty finding a plumber willing/able to fit a replacement thermal store. Consequently if you need a new thermal store to replace a Pulsacoil, I am happy to fit it for you subject to two conditions. I do not have space in my van to carry around large appliances so you will need to purchase the new thermal store and have it delivered to the flat. For the same reason I am not able to take away the old appliance and rubbish for disposal so you will need to arrange this yourself too. 


If you are local and you'd like me to replace your PulsaCoil, call or text me on 07866 766364.


Leaking Pulsacoil 2000 with front removed, showing rust marks from leaks
Leaking Pulsacoil 2000 - clsoe up below pump
Leaking Pulsacoil 2000 showing rust penetrating through unused cable clip hole

Mike the Boilerman - Independent Gledhill Pulsacoil repair specialist, covering everywhere within driving distance of Hungerford, Berkshire

Call or text me on: 07866 766364

Mike the Boilerman - Pulsacoil repair specialist, covering every-where within driving distance of hungerford, Berkshire. 

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Copyright Michael Bryant 2020

Site first published 2nd January 2007

Last updated 30th April 2021

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