Firebird 90 combi oil fired hot, hot, water!

[dazzer]

Hi Guys

This might just be the norm for a 2006 firebird 90 oil combi.

The hot water on demand is scalding hot. I've adjusted the thermostatic mixing valve to Min, and on this model it also has a central thermostatic control which I presume also controls the hot water (the control for the Central heating is to the left of control panel) I've also turned the central hot water thermostatic control to -15 (min) and this has made absolutely no difference whatsoever.

The other confusing matter is I cant see how cold water gets to the mixing valve. The top connection goes to the heat exchanger top. The bottom connection from the mixer goes to heat exchanger bottom. (Two thicker pipes also come into the heat exchanger) the central connection from the mixer goes to the flow switch and away. Am I missing something?

Firebird have said that the mixer valve usually fails cold. I'm scratching my head here, I'm thinking it might have been commissioned incorrectly originally? should I have a cold feed in to the mixer directly from somewhere?

Cheers

Darren

 

[markproperjob]

i work on many firbirds in my area.
the mixers can certainly fail hot,!
and have you checked flow switch isnt jammed 'on' superheating water?
is c/h working ok? if not, unplug flow switch and see if heating starts working correctly.
the pipe with the flow switch on it should be the cold inlet, as the water starts to move towards an open hot tap, the flow switch paddle will swing in flow direction and fire burner.