Baxi 105e Primary Circuit

[splonk]

I need to replace the DHW diaphragm on a Baxi 105e combi. The manual says that I have to drain the 'primary circuit' first, can anyone let me know the easiest way to do this?

Thanks in advance....

 

[baxpoti]

I need to replace the DHW diaphragm on a Baxi 105e combi. The manual says that I have to drain the 'primary circuit' first, .

Wow you really do learn something everyday!

Can't see why you'd have to drain the primary water!

Just shut off cold main to boiler open all hot taps undo the two 10mm nuts and loosen the grub screws and hey presto

 

[splonk]

Thanks, thought that might be the case but I thought i'd better ask!

 

[robbierazz]

Hi There,

Would this be the case if replacing the diverter valve manifold assembly too, or would the primary circuit need to be drained in that case?

Thanks,
Rob.

 

[baxpoti]

if replacing the diverter valve manifold assembly too, or would the primary circuit need to be drained in that case?

definitely drain down

 

[robbierazz]

Hi baxpoti,

Ok then, thanks for that.

Could you please explain the procedure for draining down?

I want to make sure I do it right!

Thanks,
Rob.

 

[baxpoti]

Could you please explain the procedure for draining down?.

Sorry if your not competent then get someone who is....
...
...
...
(remove the PCB, as you will flood it)

 

[robbierazz]

Baxpoti, as I understand it I need to turn off the water supply to the boiler via the isolation valve and then drain via the drain point to the righthandside of the boiler? I would also turn on any sink taps to drain any surplus water from the sanitary side of the system. Also, I assume that the boiler needs to cool down somewhat before draining?

I may not be a corgi registered heating engineer, but I'm sure I could drain the system. If you could just provide confirmation that the above procedure is correct then that will be much appreciated.

I will also remove the PCB as I appreciate that electronics and water do not mix very well!

Thanks,
Rob.

 

[ChrisR]

You have to drain the boiler water too. The word "primary" is perhaps a little ambiguous.

You either trust the boiler iso valves and drain boiler, or use a drain cock on a pipe somewhere. Make sure aav is open to let air in.

Manual is online if you don't have it , get it!

 

[robbierazz]

Hi Chris,

Many thanks for that. I agree that the term 'primary' is a touch on the ambiguous side, but thanks for clarifying for me. I have the service manual for the boiler thanks.

Also, I was thinking of reconditioning Baxi PCB's as a sideline, using the correct components of course, and wondered whether you thought there would be a good market for this? However, even though I am a qualified, time served, electronics engineer, I expect that there will be legal issues with doing this for safety reasons, i.e. board not repaired by a Baxi approved repair centre? I'd be interested to know your thoughts. If the legalities are too complicated, I will probably forget the idea!

Thanks again,
Rob.

 

[robbierazz]

Hi again,

If the primary circuit is drained down, is there any need to power flush/add inhibitor to the system when repressurising?

Thanks,
Rob.

 

[baxpoti]

10/10 for persistence

Inhibitor should be added on re-filling

Sentinel X100 is ideal

 

[robbierazz]

Thanks Baxpoti, I can be very persistant at times!

 

[robbierazz]

I've just seen that plumbworld so a tube of it for 20 quid, so will order myself some.

Would it matter if the Sentinel inhibitor was added to a system where some other type of inhibitor may have been used before, such as Fernox perhaps? Just wondered whether it was ok to mix with a different type.

Thanks, from Mr Persistence!

 

[baxpoti]

Stick with Fernox

Refer to the M.I. section 6