Bypass valve

[Johntheo5]

The boiler casing would need removing I would think to check for a 3 way valve.

I have a feeling that some mix (or cock) up may occured in the configuring of your boiler and that the displayed flow temperature could or might be taken off a probe attached to the HEX or something like that, but what is really depressing is that any engineer or whatever they call themselves would say that its normal to have this huge difference in temperatures despite confirming it with his own gear.

 

[GeddyMortgage]

The boiler casing would need removing I would think to check for a 3 way valve.

I have a feeling that some mix (or cock) up may occured in the configuring of your boiler and that the displayed flow temperature could or might be taken off a probe attached to the HEX or something like that, but what is really depressing is that any engineer or whatever they call themselves would say that its normal to have this huge difference in temperatures despite confirming it with his own gear.

Then I’m right to feel like I was being palmed off. He was adamant the boiler was all perfect. But then ofcourse he would. It’s still under warranty for 6 years more.

I too suspect there’s a cockup. Are the diverters easy to remove If there is one there?

 

[Johntheo5]

Let WB worry about the (if) 3 way valve.

Write down or take a snapshot of these (especially temperature values).

 

[GeddyMortgage]

The boiler casing would need removing I would think to check for a 3 way valve.

I have a feeling that some mix (or cock) up may occured in the configuring of your boiler and that the displayed flow temperature could or might be taken off a probe attached to the HEX or something like that, but what is really depressing is that any engineer or whatever they call themselves would say that its normal to have this huge difference in temperatures despite confirming it with his own gear.

Had a look on the inside, do you see anything resembling a 3 way diverter in there? I didn't but im certainly not technical.

Also is the red capped thing at 18seconds some sort of blow off valve to prevent airlocking etc? If that was set incorrectly could that be causing the problem?

 

[GeddyMortgage]

Let WB worry about the (if) 3 way valve.

Write down or take a snapshot of these (especially temperature values).

View attachment 402397

I'll list out what it said below. Though first worth mentioning I set the A2 to 0 and it still did the jumping from 20 to 80% thing once it reached target temp on the boiler of 80'c. So i've turned it back off now. the below is the read outs all whilst there's no CH demand.

A1 - 203
A2 - 0
A3 - 100%
A4 - this wasn't in the menu
A5 - 45.8'c
A6 - 0
A7 - this wasnt in the menu
B3 - this wasnt in the menu
B5 - this wasnt in the menu
B7 - this wasnt in the menu
B8 - 0
C1 - 0.0
C2 - 0
C4 - 3 dotted line (not fitted)
C5 - this wasnt in the menu
C6 - 1.6bar
D1 - this wasnt in the menu
D2 - this wasnt in the menu
D3 - this wasnt in the menu
D4 - this wasnt in the menu
D5 - i have a setting for this on the boiler but its not in the manual anywhere.

 

[Johntheo5]

Ensure you don't remove any casing that might compromise the boiler casing gas sealing.
If you follow the boiler flow pipe back you might see where the flow temperature is attached, if so, take your own reading as close to this as possible and compare it with the displayed flow temperature.

I wouldn't run the boiler at that 80C just now. Suggest 70C. House should still heat up eventually.

 

[Johntheo5]

I'll list out what it said below. Though first worth mentioning I set the A2 to 0 and it still did the jumping from 20 to 80% thing once it reached target temp on the boiler of 80'c. So i've turned it back off now. the below is the read outs all whilst there's no CH demand.

A1 - 203
A2 - 0
A3 - 100%
A4 - this wasn't in the menu
A5 - 45.8'c
A6 - 0
A7 - this wasnt in the menu
B3 - this wasnt in the menu
B5 - this wasnt in the menu
B7 - this wasnt in the menu
B8 - 0
C1 - 0.0
C2 - 0
C4 - 3 dotted line (not fitted)
C5 - this wasnt in the menu
C6 - 1.6bar
D1 - this wasnt in the menu
D2 - this wasnt in the menu
D3 - this wasnt in the menu
D4 - this wasnt in the menu
D5 - i have a setting for this on the boiler but its not in the manual anywhere.

Can you follow the menu instructions in post 63 to see can you get those other readings.

 

[GeddyMortgage]

Can you follow the menu instructions in post 63 to see can you get those other readings.

Im not sure how to get the other ones to appear. Or do you mean run it again when the boiler is running / CH demanded?

 

[Johntheo5]

If you can't access those values then OK.
Were you able you located the position of the flow temperature sensor?

 

[Johntheo5]

Generally in the region of 50-75% output id say.

when I fire it up it starts low % and gradually creeps up but then as it hits the target flow it stays around 50% ish.

that said i have noticed many times it'll overshoot the target, turn off the burner for 1-2mins then resume, when it resumes it'll start at a very low output % again, around 20% and creep up until back to target, then stay at target at around 45-50% output.


Feeling the boiler outlet directly beneath the boiler, photo attached. .. Left read out was flow, right read out was return. But thermometers aside even to the touch there was a massive difference between boiler lcd temp and outlet temp.

View attachment 397848

Comparatively (and I know this is silly to say) but we have a 40kw conventional boiler upstairs and with that, you turn it on, and the temperature of the flow pipe of that one is always pretty consistent with the LCD read out. Leading me further to believe something is wrong with this downstair one that we're discussing.

Slight hiccup??
The pipe where the 24.7C sensor is attached to is the GAS inlet I'm pretty sure and the Boiler Return is most certainly the one with the expansion vessel attached, so might learn something further when/if you move that sensor.

 

[GeddyMortgage]

Slight hiccup??
The pipe where the 24.7C sensor is attached to is the GAS inlet I'm pretty sure and the Boiler Return is most certainly the one with the expansion vessel attached, so might learn something further when/if you move that sensor.

Ah, I see what you mean… no, the 24.7 sensor display is in the middle but it’s metal sensor is inside some lagging wrapped around the return pipe below where the exp vessel is.

 

[Johntheo5]

I thought the "gas supply" was a bit on the hot side allright at 27.6C.

I think you're next move will be to try and convince WB to revisit (under warranty) so maybe supply them with some info which "proves" that the flowtemp cannot be 15C+ higher than your readings.
Suggest, returning the target temp to 70/75C or wherever it was before you increased it to 80C. Wait until the boiler is running constantly at a steady output for say 10 minutes, note the displayed boiler target&flow temperatures, note the % boiler modulation, note your flow&return temperature readings. Also, as proof that the boiler is outputting what the % modulation is displaying I would, during this steady running period, take a snapshot of the Gas Meter and exactly 3 minutes later, to the very second, take another snapshot, the boiler output (kW) can then be calculated pretty accurately.
Edit: You did do this gas meter tests last month so perhaps no need to repeat but migh help convince the WB people.