Monday, 25 November 2019

Intermittent water heater

The house has a gas instant hot water system.  It’s an external unit mounted on the side of the house adjacent to the back door.

Recently the unit has started to operate intermittently, which isn’t much fun if you’re about to take a shower.  Of course there wasn’t a problem when it was only Jan experiencing cold water, but more recently both of us have been affected. 

Today I took the shroud off the unit to see what’s inside.


There isn’t much to it!

Instead of a match or mains electricity it uses a small hydro generator to ignite the system automatically every time a hot tap is turned on.  The hydro generator is just a small plastic turbine in the water inlet pipe.  When a hot tap is turned on cold water runs through the water heater spinning the turbine.  This generates 1.5 Volts which is fed to a small capacitor. 


The hydro generator


The capacitor powers the spark to ignite the gas.


The ‘spark plug’

I paused to reflect before I started pulling everything apart to look for a fault.   Look for the simple things first!

It looked very dusty inside the unit.  Probably because this is where I had the bench when I was making our bed in 2017.   The first simple task was to use the garden petrol blower to remove the dust and cobwebs.    This appears to have solved the problem <I hope>


Daykin said...

Looks a bit like a very old Ascot water heater :)

Tom and Jan said...

That wouldn't surprise me. There are only so many variations on a theme! :-)