"PeterC" wrote in message
.. .
Just finishing off adding a rad. and other jobs on the CH system, then do
a
simple service on the boiler.

It's a Vaillant EcoMAX 824E, about 11 years old. The manual doesn't
mention
any sort of treatment to put in to the system and the installers said that
it wasn't necessary, but there was a small amount of black stuff in the
rads (I took them outside and shook the ****e out of them). The drined of
water was clear and colourless.

Just wondering if there should be anything put in and, if so, what to use.

Also, I've had little luck in looking for a source of spares so don't want
to go too far as there's a major gasket that almost certainly won't
survive
dismantling.

OK, 11 years of use is a goodly time, but it's off for 5 months a year and
v. little use of DHW so not much used by normal standards.

Any info. gratefully received.
--
Peter.
The gods will stay away
whilst religions hold sway

I always used an inhibiter in CHS in mine I used Fernox mb1 which is for
cast iron heat exchangers.
not sure whether he Vaillant is cast iron or copper, but get the proper
inhibiter to put in.
the system will run better, stops the boiler "kettleing" and longer for it,
as you should not get the black sludge formimg.