moselle tap cartridge/valve not unscrewing

[ms075guard-mailings@]

Hi All

I am trying to replace the cartridge on the cold tap of my kitchen sink. I am following the steps as per the "replacement guide":

Before replacing the cartridge, you will need to turn the water off. You’ll need to remove the indicator from the handle (1) and then remove the handle screw (2) by using a crosshead screwdriver. Once you’ve removed the handle (3), you can use an adjustable spanner to unscrew the valve (4). You’ll then be able to fit the replacement valves.

Unfortunately I cannot unscrew the cartidge/valve. I have used an adjustable spanner but it won't budge. A couple of times it has slipped and I can feel the edge on one of the hexagonal sides has slightly been distorted. I've used reasonable force and tried a bit of WD40 without any success.

Any tips for how I might loosen the cartridge so that my adjustable spanner can unscrew the cartridge?

 

[oldbuffer]

1. If its a stainless steel sink, pour a kettle of just boiled water over the tap, then try again. The expansion caused by the heat may be enough to loosen it.
2. If its not stainless, same trick, but water no hotter than around 80. (Say a 1.5L kettle of boiling into a bowl, then add 0.5L of cold). Some non-stainless sinks can't take boiling water.
3. Make sure the spanner is as close a fit as possible on the nut.
4. If the hexagon part of the cartridge is rounded over, try using Stillson wrench.

 

[ms075guard-mailings@]

Thank you @oldbuffer - exactly what I was looking for.