Baxi combi instant 80 he , no hot water

[flesi]

Working on Baxi combi instant 80 he, it works on heating but not hot water. New diverter valve and new plate heat exchanger installed by another engineer still no hot water. Can anyone shed any light?

 

[arran197]

Once followed a guy who'd replaced the PCB and got the knob spindles in wrong .. hot water was a bit dodge then too 🙂

I had this a few weeks ago, drive pins fitting incorrectly. The ntc sensor was no good either, but the previous engineer to me ordered a pcb. Such a simple test, but often not done.

 

[flesi]

For future reference, the block behind the DHW pressure differential valve blocked, pin was stuck in.

 

[buckley plumb]

the hw priority valve ?

 

[diamondgas]

For future reference, the block behind the DHW pressure differential valve blocked, pin was stuck in.

Stuck in pre-heat position yeh? - Never had that before but the symptoms make sense now 🙂 Cheers 'flesi'! If you check out the mi's there's a good schematic of how the valve works on pre-heat!

Always learning 🙂 :rockon2:

 

[flesi]

the hw priority valve ?

If u look on mi it's on page 37, fig.65 it's the block behind that valve.

 

[buckley plumb]

that is the hw priority valve . diverts to plate or pre heat bypass

 

[diamondgas]

that is the hw priority valve . diverts to plate or pre heat bypass

You're right mate 🙂 Sounds like the op's got stuck in the bypass position. Boiler comes on full rate and quickly drops off as the flow is reduced through the bypass in the mean time the phex gets no/little flow through it 🙂 Symptom as op states ... Interesting eh? 🙂

 

[buckley plumb]

You're right mate 🙂 Sounds like the op's got stuck in the bypass position. Boiler comes on full rate and quickly drops off as the flow is reduced through the bypass in the mean time the phex gets no/little flow through it 🙂 Symptom as op states ... Interesting eh? 🙂

that could have easily been mistaken for plate on diagnosis . hw water issues like that are the ones I struggle on as sometimes they are not the obvious

 

[diamondgas]

that could have easily been mistaken for plate on diagnosis . hw water issues like that are the ones I struggle on as sometimes they are not the obvious

Yeh agree mate... I guess that's where touchy feely takes over 🙂 However Baxi are the only manufactures I'm aware of to take up this strange way of 'pre-heat' .... ! Most others pre-heat the phex and not a 'storage' in the expansion!! You'll always be caught out mate!
I've most likely mentioned it before but as an apprentice and ever since I've been taught and learned how most component parts work individually and work in with how the appliance itself functions ... ! I don't know how folk are taught these days but for me it's been an asset..!

 

[Billy Bob Bob]

For future reference, the block behind the DHW pressure differential valve blocked, pin was stuck in.

one of the possibilities i gave in post 10 hope you did not get ripped for it there keenly priced with abkot

 

[buckley plumb]

Yeh agree mate... I guess that's where touchy feely takes over 🙂 However Baxi are the only manufactures I'm aware of to take up this strange way of 'pre-heat' .... ! Most others pre-heat the phex and not a 'storage' in the expansion!! You'll always be caught out mate!
I've most likely mentioned it before but as an apprentice and ever since I've been taught and learned how most component parts work individually and work in with how the appliance itself functions ... ! I don't know how folk are taught these days but for me it's been an asset..!

not much out there in training info mate unless you work for one of the big companies .

 

[Billy Bob Bob]

not much out there in training info mate unless you work for one of the big companies .

experience is the biggest teacher,everything i know is self taught and sometimes painfully gained