BAXI Combi 133 HE Plus timer issue

[johnnyduk]

Hello

I have one of these, and I have just switched the central heating on for the winter, but.....It seems to be ignoring the external timer, the external timer is working OK, it is closed when it should be and open when it should be. But the central heating comes on regardless and relies on the internal thermostat. Is this just a main PCB problem? I don't want to waste £300 + when I can do it myself for 130 ish

Many Thanks

JohnnyD

 

[kevplumb]

has it worked ok in the past

 

[johnnyduk]

Yes for years it has worked fine, it is not a new install....

 

[kevplumb]

the external timer is working OK, it is closed when it should be and open when it should be.

how did you check

 

[johnnyduk]

When the timer is off, there is 240 volts on the supply cable but not the return so the circuit is broken, when the timer/stat is on there is 240 v across both wires to the boiler so current is flowing...

 

[johnnyduk]

The guy who installed it who is miles away now just called to say it could be a stuck diverter valve (honeywell box) ?

 

[Agile]

It could well be that the DHW is stuck on and creating a ( false ) demand for DHW and the boiler ends up putting the heat into the CH.

For once your installer knows how they work!

Look at the pin and switch.

Tony

 

[johnnyduk]

Hi Tony

Many thanks for this, I don't think the DHW is stuck on though, as with the central heating turned off (summer mode) the boiler is OK. With the honeywell vc4012 on the boiler, the actuator will not move on the head, If I remove the honeywell vc4012 the actuator moves freely, it seems the 3 way divertor valve is stuck (well I cant move it) So its not the head, but the valve that seems stuck, could this be the problem?

JD

 

[johnnyduk]

Its not the divertor valve or head...they are both functioning correctly

 

[baxpoti]

So its not the head, but the valve that seems stuck, could this be the problem?

You seem to have answered your own question

 

[johnnyduk]

Yes i did really, I thought the valve was stuck, but it isn't, the valve and actuator are doing there thing ok, so its something else

JD

 

[baxpoti]

I'd start with thoroughly checking and if necessary (ordering and) changing part 241361.

 

[johnnyduk]

OK I am going to order a 3 way divertor valve today, how confident are we that this is the problem, like I say the boiler is functioning normally, its just not listening to the external timer/therm.

JD

 

[NevFletcher]

Hi,

my boiler is doing the same as yours, i doubt it will be the diverter valve as it makes no difference if the electric control plug is connected to it.

I have had a chat with Baxi and ruled out frost protection as all the sensors are reading the correct resistance. They are telling me if there is no voltage (230 volt) at the orange wire ( at timer connector strip) then the problem is with the PCB.

My boiler works perfectly other than pressing winter button starts heating and will not shut off till re-pressed.

If I can't fix it I am probably going to find the wires at the winter switch and take them through the timer contacts - using as a switch - not switching 230 volt, just volt free switch.

Nev.

 

[johnnyduk]

Hmmm very interesting....the PCB was my first guess but Baxi wouldn't talk to me, can you keep me in touch with progress please, I will measure voltages at the weekend, and if it is the PCB, I may do the same as you and wire the timer via the CH switch if possible.

Many Thanks

JD