Hot water not getting hot enough

[Parcival]

We have a Vaillant EcoTec boiler for our heating and hot water.

It is a sealed system with a hot water tank. Heating works fine but hot water is not getting as hot as it should.

It was fine last week and then we had the heating on for a few hours. The water gets hotish but not as hot as it should.

Boiler fires up ok and no error messages. The pipe leading from the boiler up to the cylinder feels hot but the water is not getting anywhere near as hot as it should.

Any help would be appreciated...

 

[lightning]

Check cylinder stat is at 60 degrees,
Does boiler fire up for hot water only.

Paul

 

[Parcival]

Thanks - yes cylinder thermo is set to sixty degrees and boiler does fire up when set to water only.
I am wondering if air is in system....

 

[lightning]

How long do you leave the hot water on for, what is your boiler stat set on.

Paul

 

[Parcival]

Water has been set for 30 mins in the morning and 30 mins in the evening which has always been fine.

Don't use much as electric shower, plus dishwasher that is cold fill.....

 

[Agile]

That may mot be long enough now that the water enters colder.

I always suggest at least 90 minutes is timed and preferably 120 minutes.

The boiler stat needs to be on at least 70 C otherwise it will never satisfy the 60 C stat.

Tony

 

[Armo74]

Energy will not be wasted as the cylinder stat will shut the boiler off when it is satisfied anyway.
Better to have it on to long than not long enough.