please help boiler problem !!!!

[geordie1933]

baxi combi 80 3 way valve not working on ch. rad very hot no control with themostat turned right down. hw. ok. pressure in the green ok.
retired service engineer just need advice what to look for.
thank you

 

[Agile]

Your posting does not make much sense to me.

You seem to be saying that the CH is not working but the rads are hot !

Can you identify the boiler more closely?

Tony

 

[Gasguru]

What thermostat turned down - room or the boiler heating temperature control?

Why do you think the diverter is not working - seems fine to me if the DHW and heating works.

Do you mean a raditor is too hot and the TRV doesn't work?

Call yourself a retired service engineer - talk sense.

 

[geordie1933]

the boiler is a five year old baxi combi 80 eco the rads are very hot with the stat. right down hot water ok .is this a 3way valve problem

 

[Agile]

Sounds more likely to be a CH NTC to me !

Might also be a gas valve min/max setting involved.

If I remember rightly on the ECO you can set the CH power output to match the heat requirements but few installers do that.

Are you a retired heating service engineer or a TV service engineer for example?

Tony

 

[Gasguru]

You still havn't told us what stat, do you mean a room thermostat or the boiler temperature (potentiometer control).

If its the boiler control have you checked the spindle hasn't sheared off otherwise Tony's suggestion.

 

[geordie1933]

no room stat. just stat on boiler.have you any idea why rads are very hot.if the boiler stat is turned up the boiler cuts out. all this info i am getting second hand. before traveling to site

 

[Agile]

If I remember correctly, if the PCB is removed or changed its possible for the knob spindle to be refitted 180 degrees out of position with the potiometer itself.

Usually that can be felt as a slight roughness as the spindle is rotated over its endstop.

Tony

 

[geordie1933]

thanks for your help tony i have been retired since 1990 and worked in electrical switch gear industry. all the best eric NTC can you explain please