Willis External Immersion Heater

[ericmark]

Moving to a house with oil central heating, and it seems the owners use an immersion heater in the summer, not sure if this is really a good or bad idea, but with a cistern the idea of heating it all when only a small amount of hot water is required, also seems wrong, however to fit two immersion heaters would need a tank change, and even then only two options.

So looking at the Ulster idea with the Willis External Immersion Heater where either using thermostats or simple timer we can adjust the amount of water stored very easy,

the idea seems good, it heats from top down, so can set to few inches to have hot water at taps, a foot for a shower or 3 foot for a bath.

However never seen one in use, so any reports on how well it works, and will I get a Welsh plumber to fit it, or is this some thing only the Irish ken?

 

[flameport]

and it seems the owners use an immersion heater in the summer, not sure if this is really a good or bad idea

Unless the electricity is from solar panels, or is exceptionally cheap, it's a bad idea.
Oil is far cheaper then electricity, unless the tank is too small and you then have to buy oil in December.

So looking at the Ulster idea with the Willis External Immersion Heater w

Forget it.

Modern hot water cylinders have tiny losses, the difference between heating it all and attempting to heat some of it is next to nothing.
If the cylinder is old, spend the money on a new one and some proper pipe insulation.

 

[ianmcd]

Unless the electricity is from solar panels, or is exceptionally cheap, it's a bad idea.
Oil is far cheaper then electricity, unless the tank is too small and you then have to buy oil in December.


Forget it.

Modern hot water cylinders have tiny losses, the difference between heating it all and attempting to heat some of it is next to nothing.
If the cylinder is old, spend the money on a new one and some proper pipe insulation.

I have never actually seen one but Googled it after reading that post and thought it was a fair idea , would be interested to hear from anyone that has installed one

 

[Donald Dovaston]

I have just seen this enquiry and thought I could offer some helpful information.
I found out about Willis heater about 5 years ago after installing solar PV panels, rather than let excess solar power go to the grid, I installed a Willis heater to the the outside of a new tank that I installed, it is connected to the solar PV starts to heat the water as soon as sun is up and I will have a full tank of hot water later in the day for free.
The Willis heater works extremely well, I only installed one unit plumbed from bottom of tank to top and depending on the amount of water I need I can get a shower for instance after 15mins if the solar system is bypassed.
Ever since I installed it I have had a full tank of hot water.
If anyone picks up this thread I would be happy to answer questions if I can.

 

[vonny232]

I have just seen this enquiry and thought I could offer some helpful information.
I found out about Willis heater about 5 years ago after installing solar PV panels, rather than let excess solar power go to the grid, I installed a Willis heater to the the outside of a new tank that I installed, it is connected to the solar PV starts to heat the water as soon as sun is up and I will have a full tank of hot water later in the day for free.
The Willis heater works extremely well, I only installed one unit plumbed from bottom of tank to top and depending on the amount of water I need I can get a shower for instance after 15mins if the solar system is bypassed.
Ever since I installed it I have had a full tank of hot water.
If anyone picks up this thread I would be happy to answer questions if I can.

Hi Donald, I also discovered a Willis Heater while looking for some kind of "Inline water heater" to try and supplement my heat pump/electric immersion boiler which is going to get very expensive this winter.

Question - How do you regulate the shutoff temperature for the willis heater given its bad practice to use the mechanical stat to turn off the power when the water gets too hot (i.e. 75 degrees or so)?

 

[Johntheo5]

I would love to see a photo of the installation in post #4 above as it needs very careful installation with 22mm piping and (in the one I gave some advice on) the installation of a pipe stat to work properly, the immersion stat in (my "case") even after renewal would not give proper control but the pipe stat works quite well with the immersion stat(s) operating in a supervisory capacity, would also suggest that a 2/2.5kw element will work better than the normally supplied 3kw, if in fact a external immersion can be sourced with the lower power element.