Replacing the 3-port mid position valve on a Gledhill Systemate III?

[la_tt]

I need to replace the 3-port mid position valve on a Systemate III. I have already replaced 3-port valves, but never on a Systemate III.

1) As it is connected on 28mm pipes, I understand that the 3-port valve’s part number is XG142. Has it got to be an original part from Gledhill or are there compatible 3-port valves available from plumber’s merchants?


2) What is the best step-by-step procedure for draining the system, replacing the valve, refilling the heating system and checking that the valve is working properly? I want to avoid damaging other elements of the system and would like to know if there are things specific to Systemate III that I need to look out for.

Many thanks for your help.

 

[migoplumber]

horrible things to work on i used to think. i rang gledhill direct for advice on a different problem, that i couldnt solve - what a customer service ! would reccomend you ring them, speak to a tekkie (they are tekkies there - not librarians) ask him, buy the part you need from them direct.

 

[la_tt]

Many thanks for your advice. If I am correct it is so expensive to call them. £1 a minute!