Replacing a Willis Immersion heater

[JoeK]

Hi Folks,
I'm new to this Forum - not a plumber but an experienced DIYer :~)

Recently my Willis heater (external Immersion heater) packed up. I've got a replacement and am researching how to replace the old one. It looks like a simple enough job :confused5: - drain the main tank, unscrew the old heater and replace with the new one. Just wondering is there anything I'm missing here ?

The main tank has a thermotstat - does something need to be done with it before draining? Someone mentioned that these might be pressurized?

Thanks in advance for any advice!
Joe.

 

[Dotty]

It won't be unvented. As you say, drain down and replace.

I would advise you discoonect it from the spur first, remove the old one, wire up the new one, fit it, test for leaks then connect it to the spur.

Good luck!

 

[BLOD]

Is it a Willis solar syphon ?

 

[Dotty]

Is it a Willis solar syphon ?

no, it's an external DHW heating element.

 

[JoeK]

Thanks croppie.

Gave it a go today and stumbled at the first hurdle - draining the tank.

I attached a hose and proceeded to open the nut at the bottom (red arrow on picture) which I thought would open the valve and release the water - but instead the water started to come out of the nut itself.

I'm guessing its not a drain valve after all ?

EDIT - for some reason I can't add a URL to the picture, get an error saying theres a limit on URLs per Thread !

 

[Best]

If you are lucky to have a draincock on the hot cylinder, it will often be blocked with corrosion or seized. If it does open, it will likely leak from the spindle as most of them have no seal there.
It is very common to have to drain cylinder by removing the fitting from the top of cylinder & pushing a hose with a copper pipe attached to it down to the base of the tank. Then start a syphon to drain.
Warning to you - be careful to take note what fitting is on the tank for the bottom pipe from the Willis heater! If it is not a factory 1/2" tapping, but a joint with rubber washers called an Essex Flange, then it will leak seriously badly if touched & needs replaced!

 

[Best]

There is a way of draining & changing a Willis very very easily, but it is not something I want to tell people. Sorry! :smile:

 

[Dotty]

There is a way of draining & changing a Willis very very easily, but it is not something I want to tell people. Sorry! :smile:

Bloody quickly?

 

[Best]

Bloody quickly?

Maybe not really quickly, but def very easy & lazy way.
Or there is another way which is both easy & fast, but you will guess that one perhaps.
I'll pm you. Guess there are no Willis heaters in rest of UK.

 

[JoeK]

Anyway you could PM me that Best?

 

[JoeK]

Hi Croppie, any reason why I can't attach a link to a picture on here? I keep getting an error msg saying theres a limit on URL per thread - seems like theres only one a the minute!

 

[Dotty]

Hi Croppie, any reason why I can't attach a link to a picture on here? I keep getting an error msg saying theres a limit on URL per thread - seems like theres only one a the minute!

Purely and simply because you're a newbie. We had to put some fairly strict measures in place a little while ago after a sustained spammage.

 

[Best]

Anyway you could PM me that Best?

Only would result in people trying my methods & flooding a house if they don't know what they are doing.
If you haven't an Essex flange on cylinder for the Willis return pipe connection, then you should be safe to just drain it from the top, as I have described in first post.
Assume you are from Northern Ireland?

 

[Gray0689]

Jump it

 

[kay-jay]

Only would result in people trying my methods & flooding a house if they don't know what they are doing.
If you haven't an Essex flange on cylinder for the Willis return pipe connection, then you should be safe to just drain it from the top, as I have described in first post.
Assume you are from Northern Ireland?

One thing I would add to your first post for the benefit of the op is that before syphoning the cylinder, the header tank must be drained.[emoji41]

Easiest way is run hot tap til it stops running (isolate mains stop tap first)

 

[Best]

One thing I would add to your first post for the benefit of the op is that before syphoning the cylinder, the header tank must be drained.[emoji41]

Easiest way is run hot tap til it stops running (isolate mains stop tap first)

He could just turn the valve off on the cwt that feeds the hot tank, but if it is a gatevalve he might be wise to stick a bung on the outlet inside the tank. Or he could turn the mains off & drain the cold tank as you suggest. Then he might get airlocks in both hot & cold pipes though. :smile:

 

[kay-jay]

He could just turn the valve off on the cwt that feeds the hot tank, but if it is a gatevalve he might be wise to stick a bung on the outlet inside the tank. Or he could turn the mains off & drain the cold tank as you suggest. Then he might get airlocks in both hot & cold pipes though. [emoji2]

Yep. I just wanted to clarify for his benefit that trying to syphon the cylinder wasnt the first step....