Neff washer / dryer not heating – again.

Hi, and thanks in advance for any help.

NEFF V6320X0GB/03

So, my unit stopped heating last year and I called someone out to check it over – he reset the limit stat, said if it went again the stat would need replacing. I wasn’t very happy as a limit stat generally trips for a reason unless it’s failed, and I don’t see how you can tell that unless it doesn’t reset at all. I’m pretty competent with mech / electrical engineering but domestic appliances are a bit of a mystery so far.

Anyway, logically this pointed towards lack of air flow, obstruction, temp stat out of limit etc so I did a strip down. The condenser was virtually blocked, and the hot air duct had some lint in and around the heater so after cleaning it and resetting the stat it worked fine for a few months. It’s now tripped out again and before I strip it out again I’m looking for some help please.

Specifically,

Anything else I need to clear out apart doing what I’ve already done?

How can I check that the fan is working properly? – is it just on / off or can it vary in speed if it’s faulty?

It struck me that if the re’s a limit stat, there’s likely to be a control stat / sensor somewhere which I don’t recall seeing. Is there one, and where is it likely to be?

Given that I virtually have to take the kitchen apart to get at the thing, is it worth replacing the limit stat and the control sensor (if there is one) just as a belt and braces precaution?

Any help greatly appreciated!