Combi Boiler - Hot Water

I'll need to go to the supermarket. Clearly rubbish, boiler cut out twice today.

Phone them again on Monday.... sigh...
 
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They were here for a while. Apparently they now think the cause is that the cold water coming into the house is too warm. 22 degrees.

If that’s the case it’s borderline for undue warming on your water supply, in which case this would need to be investigated. I would try and measure it yourself or ask them for proof of this. As Ian says, nothing to do with that.
 
I’m thinking poor flow conditions. I would love to have a go at this.
Is the bypass wedged open.?
Try running the shower with a hot tap open at the same time.
This would rule the flow problem out.
 
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Once again, thank you all for the replies and help.

I’m thinking poor flow conditions. I would love to have a go at this.
Is the bypass wedged open.?
Try running the shower with a hot tap open at the same time.
This would rule the flow problem out.

By poor flow conditions, do you mean hot water flow conditions? They did find the factory fitted the wrong flow restrictor in the boiler, as the hot water flow rate used to be significantly lower than the cold/mains pressure. It's higher now. When you run two hot taps at the same time (i.e. shower and basin hot tap) the flow decreases for sure. As for the bypass, I don't know, but I can investigate.

I had the suspicion (and relayed this to the previous couple of WB engineers) that it has something to do with the hot water flow rate

and ask for an experienced engineer to visit next, tell them you have had enough trained monkeys.

We already had a senior engineer. Now I get the feeling the guys at the call centre are getting fed up with me!

Just to clarify does this happen from all hot taps ? And the water gets scalding hot before cutting out ?

Yes it happens from all hot taps. And yes the water gets scalding hot. We experience it most in the shower, as obviously that's where time is spent(!) and doesn't happen every time (maybe 50% of the time - e.g. since the engineer came on Friday there's been 5 showers, during 3 of which the boiler cut out). So every so often you can have a normal shower with no problems, which has made diagnosing quite difficult.
 
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Once again, thank you all for the replies and help.

We already had a senior engineer. Now I get the feeling the guys at the call centre are getting fed up with me!
- tough sh**, just carrying on pestering them being polite. You have every right to get it fixed.

Do you know if the pump has been checked?
 
- tough sh**, just carrying on pestering them being polite. You have every right to get it fixed.

Do you know if the pump has been checked?

Not sure whether the pump has been checked. I've called and they're coming again on Friday. Another day off work :unsure: I'll formulate another list of things for them to check..

Check you inbox. I have sent you the name and contact details for a person a few levels above the service desk.

Thanks a lot - I'll keep the ammo in my back pocket and see what happens on Friday on their 5th visit. The installer is calling his rep tomorrow to ask what the hell is going on. If we get nowhere this week, I'll escalate then.
 
If you go to your boiler. Press and hold the return/spanner button for 5secs this will take you to a maintenance menu. From here use the hot water up/down buttons to scroll to the 'blocking list'. If there are any errors on there make a note of them and let us know. It's on page 48ish of your maual.

Also run your shower/hot tap and make a note of the temperature your boiler shows on the LCD screen see how high it goes and if the flame goes symbol goes out and us know.
 
If you go to your boiler. Press and hold the return/spanner button for 5secs this will take you to a maintenance menu. From here use the hot water up/down buttons to scroll to the 'blocking list'. If there are any errors on there make a note of them and let us know. It's on page 48ish of your maual.

Also run your shower/hot tap and make a note of the temperature your boiler shows on the LCD screen see how high it goes and if the flame goes symbol goes out and us know.

1 error... 351 flow sensor fault......

Wouldn't a WB engineer check for error codes?? Doesn't have a time stamp and I didn't know this existed.

I'll monitor the temperature at which it cuts out during showers this evening.. needed after this bloody hot weather!

Thanks

Plank
 
If there's just the 1 and it's 351 (you said they changed the main sensor so could have occurred then) then that's telling me the boiler isn't blocking the operation during hot water demand.

If you go to page 42 in your manual on the right hand side is an explanation into how you can access the the 'benchmark menu' with the shower/ hot tap running make a note of all three values. Flow temp, hot water temp and flow rate.

There should be about 10/12 degrees difference between flow temp and hot water temp at max flow rate which is about 12 liters per minute
 
OK, understood. That makes sense.

In response to the benchmark menu:
CH Flow temp 62
DHW outlet 59
DHW flow rate 6.2

An odd thing just happened too. Hot water was running fine throuh the bath taps, cold water added to get shower temperature, then when switched to the hose/shower head, the boiler switched off? Water still coming out of shower head at same rate. Wouldn't start again. My partner ended up having a bath.

This is starting to look more like a flow problem? But then why does it seem so intermittent

Edit: Scrap that, we get 3l/min at the actual shower head (6l at the taps). As it fluctuates, it cuts out at 2.5l/min. Any way to reduce the flow at which it cuts out?

Edit #2: OK so I think that makes sense, as it has got worse (I.e. cuts out almost every shower) when I use a particular head (presumably restricting flow). It is less frequent on the main taps and on the kitchen. This suggests to me that there is a blockage or restriction somewhere?
 
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There's your issue then mate. It takes a minimum of 2.9 LPM to active the flow switch to get the boiler to produce hot water.
If it drops your below this then the boiler doesn't think it needs to give you hot water. The boiler seems to be doing its job.

Is your cold water flow significantly higher than your hot water flow?
 

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