cab heater

[maxcell]

190, 2.00, pet, man.
I am reposting, hoping to have somebody read this who didn't read it before, Cab heater does not work, I am convinced the heater matrix is not blocked, tests prove by runing an external hot water supply direct to the matrix delivers heat to cab, so for some reason it would appear that there is little to no water circulating through the matrix , pump and stat new (6mths) valve working.

 

[mersum1es]

Duo valve (is there one in 190?) jammed?

 

[Tinkerer]

+1^^ they do seem to be a problem, there a few posts on here and might even be a howto.
Yep try this http://www.mbclub.co.uk/forums/howto/26888-howto-clean-duovalve-w210.html

 

[Sp!ke]

The duovalve is a common problem which can be tested quite easily.

I had a similar issue on my 190 and cured it by running descaler through the entire system for a couple of days before flushing the system thoroughly. There was a ton of stuff that came out.

Are you absolutely sure you've not got trapped wind? If a direct hot water supply works then it does point to there still being air trapped in there, possibly through a small leak in the matrix itself.