Just had an ACK42 fail after just over 5 years. Of course, Sod's Law
arranged for it to fail in the fully-open position, and we didn't
discover it until after there had been quite a bit of rain!

Anyway, I intend to get a replacement, and there are many suppliers
online at quite a range of prices. However, I see there is now an ACK5
(eg see
http://www.vent.co.uk/natural-ventilation/products/topp/ack4-actuator.php):

* The ACK5 has now replaced the ACK4 actuator
* the UK's most popular actuator has been Improved with greater reliability

Anyone got any experience of this updated version? IMHO, new versions of
almost anything are rarely more reliable than old versions. Is it just a
"drop-in" replacement?

--

Jeff