Worcester Bosch 4000 Not providing DHW, occasionally

[Post and beam]

I had a boiler engineer come to look at our new combi( hate it) Becuase sometimes it does not fire up and provide hot water for washing. Radiators are fine as far as i can tell.

The only way i have found to get around it when i am standing in front of the boiler cursing it for freezing my bits in the shower, is to keep pressing buttons through the display until it notices it needs to heat from 12 degrees C to 55.

Never see an error code and last year they replaced the flow switch, no improvement.

Engineer has blamed the mixer taps for 'cross leakage' creating a cooler than optimal water supply to my delicate bod' WTF!

Also thinks that me pressing every button i can see is evidence of the boiler behaving as it should, because.' you press for heat and it starts the burner'. This ignores the fact that standing in the shower and turning on the tap should elicit some hot water.

 

Can anyone shed light on what appears to be nonsense from this representative of Worcester Bosch please?

Thanks in advance

keith

[marshian]

Is it just for a shower that it fails to provide HW?

 

Does a bath/sink tap on fire it up??

 

How many litres per min does the shower flow (and what temp do you have the shower set too) some modern shower heads are capable of giving a good shower at very low water flows - down to as little as 6L per min

 

I don't have any knowledge of combi boilers (i've stuck with a tank and intend to continue with one) but I would expect that they have a min flow required to kick the boiler into action - if the water temp is set to say 50 deg and the cold coming in on the other side is at 10 deg then to get a 35 to 40 deg shower at a 6L per min flow the boiler is only going to be asked for say 4 L per min (rough math)

[Temp]

Most mixers have valves to prevent cross flow but check. If they don't this can sometimes allow cold to flow across the mixer back up the hot and around to a hot tap. 

 

If there are isolators on the shower try turning one off and see if that fixes the problem at a tap (the shower won't work obviously but it might confirm the fault)

 

Check the mains pressure and flow rate meets any minimum spec for the boiler.

[Post and beam]

13 hours ago, marshian said:

Is it just for a shower that it fails to provide HW?

No, it is any request for hot water. Its just that a cold shower is not fun so thats the most annoying.

Water pressure is very good.

 

Even if the cross leak thing were true it would not explain the fact that when i need to stand in front of the boiler and press all the buttons i can see a HW temp of 12 degrees C and the boiler light not lit. This is with the shower tap on full by the way.

To my mind its a faulty boiler and unless someone from Worcester can come up with some evidence to the contrary i will continue to press them for a replacement.

[marshian]

1 hour ago, Post and beam said:

No, it is any request for hot water. Its just that a cold shower is not fun so thats the most annoying.

Water pressure is very good.

 

Even if the cross leak thing were true it would not explain the fact that when i need to stand in front of the boiler and press all the buttons i can see a HW temp of 12 degrees C and the boiler light not lit. This is with the shower tap on full by the way.

To my mind its a faulty boiler and unless someone from Worcester can come up with some evidence to the contrary i will continue to press them for a replacement.

Well it's certainly not right - if HW request from any tap doesn't result in HW delivered to the tap - I'd be pushing WB for further investigation/repair/replacement

 

What good is HW on Demand (AKA combi boiler) if you have frig around at the boiler to get to to kick in