faulty 3port

[mkflow]

hi,
can a faulty 3 port divertor valve not switching over to c/h cause boiler to overheat and display f4 on glowworm??

 

[Blake]

Need a bit more info, what model glowworm? does the pump continue to run once HW is satisfied and it should be switching over the CH?

Can you manually open the valve and lock it in the open position to see if that stops the error code?

 

[mkflow]

no you cant manually move valve as motor ---- . when h/w satified boiler goes lockout

 

[mkflow]

glowworm flexi hx 18 on o/v system

 

[donkeeboy]

Hi, I just had a similar prob, but it overheated for me when the room stat reach temperaature (whiilst HW+CH was on).

See this thread http://www.ukplumbersforums.co.uk/central-heating-forum/16784-replacing-grundfos-15-60-selectric-pump.html (The post title is misleading)

In the end, I just removed MV, shook it (something rattled inside), put it back on and it sorted the problem! So yeah, a dodgy MV would appear to cause these sorts of problems.