Baxi 105E Luke warm water

[pbutterworth]

Hi,

I have a 4 year old Baxi 105e and for the past couple of days wont heat the water up fully.

Even with the water temp set at full, it only manages to heat the water up to luke warm. The lamps on the boiler indicate that all is OK, but the temp lamps dont go above 50c.

It's currently set in water only mode (ie no heating).

Any ideas?

Thanks

Paul

 

[fitz1]

diaphram on diverter valve or hot water hx scaled. both easy to sort out

 

[pbutterworth]

Thanks for the prompt response. As it's not been gradual, isnt scale unlikely? It literally stopped heating properly overnight.

Is the diaphragm possible as a DIY job, i'm reasonably competent, or should I always leave boiler fixes to the experts.

 

[pbutterworth]

I've been looking at the technical manual, and it looks pretty straight forward to replace the diaphragm to me. Could you let me kniow which of the following diaphragms it is I need to order, i assume it's the 3 way valve one ? The technical document I have doesnt show a part number for this valve, but it does show a break down.

Thanks
Paul


COMBI 105E (BAXI)
DIAPHRAGM - PRESSURE DIFF VALVE
Order no.: 35605 Price: £ 5.05

COMBI 105E (BAXI)
DIAPHRAGM (3 WAY VALVE) #
Order no.: 35604 Price: £ 5.05

COMBI 105E (BAXI)
DHW DIAPHRAGM 105 #
Order no.: 37614 Price: £ 4.77

 

[Agile]

If the boiler fires up on DHW demand then I would not expect the problem to be with the diaphragm.

If you run the hot water only for about five minutes then do the radiators get hot instead of the water?

If not, then as a first check I would let the boiler become cold and measure the resistance of each of the two NTC temperature sensors. Should be about 10 K.

If the radiators do get warm then I would expect a diverter valve fault although on the mechanically operated type thats unusual if the diaphragm unit is OK.

As a first step you could disassemble the diaphratgm unit and see if the inner pin is moving freely. You will also see the diaphragm to inspect it.

If not then there may be a considerable amount of disassembling of the manifold body and this should not be rushed into until we are convinced the problem lies there as its a fairly unusual fault.

At a much earlier stage I would be checking the gas settings as thats easy for a CORGI registered engineer.

Tony

 

[pbutterworth]

Tony,
Thanks for your help. You arent corgi registered by any chance are you?

I'm based in SE13, if it's local I may be interested in your help.
If so email me on [email protected]

regards

Paul

 

[Agile]

I do have to be CORGI registered but this is only required for working on gas related aspects.

Unfortunately you are South of the River and I am North !

You can probably do many of the initial checks as outlined above.

Tony

 

[pbutterworth]

Well I have done the first check, and the rads dont get hot. If i only let the water run slowly it does get hot, and the lamps on the front light correctly. When i run the water with some force, it only gets luke warm. It behaves as if it's starved of gas.

I'll borrow a multimeter tomorrow and check the sensors. I assume I need to drain the rads before I remove the diaphragm unit.

Thanks
Paul

 

[Bish Bosh]

gas pressure needs checking first off

 

[stuart_adair]

Folks I've got a very tiny leak from the hold in the nut at the very end of the diverter valve, right by the microswitch. Does the smart-money reckon that this could be the diaphram ?

Stu

 

[BigBurner]

gas pressure needs checking first off

If there is a gas hob, does that work OK when all burners are are full on. This test can sometimes indicate a failed meter regulator.