Willis External Immersion Heater Install

[AlanIrl]

Hi
I'm planning to install a Willis this week but have a question about how it may not operate as hoped.

My question is, if the immersion is powered off, and the cold water feed is split between the water tank infeed and the Willis infeed ..... when someone turns on a hot water tap, what prevents the cold water going straight through the Willis without been heated and straight onto the tank output pipe ... thus mixing / cooling the water coming from the tank?

And taking that idea a little further, if the cold feed line has a pump pressuring the system would the problem of cold water flying through the Willis when a tap is drawing to water be worse?

 

[CBW]

Maybe it works with a flow switch? Perhaps contact the manufacturer?

 

[Agile]

It is important that they are always fitted with the cable connection at the bottom.

I presume that as they are on a 15 mm pipe and the cold in and hot out are 22 mm then there will be a much higher flow resistance so little cold water will flor through them.

But please be aware that they are a rather bodge solution to a cylinder without an immersion boss.

A clever person can cut a hole in a copper tank and solder an immersion boss into position. A rather better solution.