It is in comfort mode and the dial is higher than the dot. I'll call Viessmann today.
Thanks for your help.
New Viessmann - Hot Water Takes Ages
- Thread starter Toki
- Start date
It is in comfort mode and the dial is higher than the dot. I'll call Viessmann today.
Thanks for your help.
Would be interesting how you solved this problem? The same issue with may Viessmann heater. It is definitely not a piping fault. I have older Viessmann heater and it starts right after you tap the hot water. And it is working more then 10 years already. Is there any way how to solve this delayed hot water issue?
Very appreciate for help.
Very appreciate for help.
I know this is an old thread but all the issues regarding slow delivery of hot water from a new veissmann 100wd boiler are happening to me. My investigation suggests that on occassion when hot water is turned on the boiler is very slow to get to 100% modulation. The temperature of the water pipe at the boiler confirms a slow rise . Nothing to do with pipe sizes all is 15mm with very high mains pressure available.
I really do suspect a design fault in the temperature control stability as the engineers could find no faults on any components. how many others out there feel the same way?
how quickly should a combi boiler deliver hot water at its output( not at the tap) assuming perhaps input cold water at 10deg and requesting 35 deg out?
I really do suspect a design fault in the temperature control stability as the engineers could find no faults on any components. how many others out there feel the same way?
how quickly should a combi boiler deliver hot water at its output( not at the tap) assuming perhaps input cold water at 10deg and requesting 35 deg out?
The boiler HEX and PHEX contents + the PHEX mains (secondary) contain probably only around a very max of 10L requiring 10*(35-10)/860, 0.29kWh and if 25kW available then 0.29/25*3600, say 41 secs for water to reach 35C at the boiler outlet, this assumes that you only open the hot tap enough to get the boiler to fire, say 3LPM, the boiler should then ramp down to 5.23kW to maintain this flowrate at 35C.
Have you tried it at this very low flowrate? and if so how long is it taking the boiler to ramp up to 100% and how do you know that it has (or not) ramped up, also, the important bit, how long to reach 35C at the boiler??.
Have you gat a link to your exact model, Viessmann Vitodens WD????
Don't know whether it has a loading cylinder or not?.
Have you tried it at this very low flowrate? and if so how long is it taking the boiler to ramp up to 100% and how do you know that it has (or not) ramped up, also, the important bit, how long to reach 35C at the boiler??.
Have you gat a link to your exact model, Viessmann Vitodens WD????
Don't know whether it has a loading cylinder or not?.
Last edited:
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