Combi Boiler - Hot Water

[Toki]

I have a Viessmann Vitodens 100 and the hot water takes ages to come through. I've asked on here previously but done some more tests myself.

This morning the display temperature was at 46 deg C before I turned on the hot water. As soon as I turned the tap on, the boiler fired up, slowly and the display temperature began to drop to around 42 deg C after 30 seconds or so. At this stage, 30 seconds in, the boiler started cranking up to full power and temperature began to rise and within another 30 seconds was up at over 60 deg C.

The installer recommends installing a hot water pipe to the kitchen as the run of pipes is from the boiler in the garage, upstairs, then back down. However, if the boiler itself is taking around a minute I can't see this making much difference.

Compared to other combi boilers, my dads, for example only takes 15 seconds, his is in the loft.

Is it usual for a boiler to take a minute to get up to HW temperature? I have tried comfort and eco settings but it doesnt make much difference at all. I even had Viessmann have a look at the boiler last year but they found nothing wrong. I just can't understand how my dads is almost instant and mine takes a minute. Thoughts please?

Thanks in advance.

 

[Toki]

Bump, can anyone assist? Is it typical for a combi boiler to take a minute to get up to temperature for hot water? See above. Thanks.

 

[Dan Robinson]

Does this boiler not have a pre-heat function for hot water?

If so best check that it is turned on.

Otherwise - from a cold start it could easily take 30 seconds to get up and running temperature wise.

Does the boiler still take its time if it is up to full temperature in heating mode?

 

[romeo26]

This is a most important information. This morning the display temperature was at 46 deg C before I turned on the hot water. As soon as I turned the tap on, the boiler fired up, slowly and the display temperature began to drop to around 42 deg C after 30 seconds or so. At this stage, 30 seconds in, the boiler started cranking up to full power and temperature began to rise and within another 30 seconds was up at over 60 deg C.
However, if the boiler itself is taking around a minute I can't see this making much difference.
Compared to other combi boilers, my dads, for example only takes 15 seconds, his is in the loft.

 

[Dan Robinson]

 

[ALEC1]

for preheat to work properly it needs a sensor on the plate I suspect...I don't think the viessmann 100 has that neither do other bottom of the range boilers

what is you dads boiler...

 

[Toki]

My boiler has an "Eco" and a "Comfort" setting. The comfort setting keep the heat exchanger warm I think the installer said. When on comfort, I can hear the boiler fire up for a few seconds during the day and night even when heating and HW is off.

Not sure the make of my dads, I know it was a cheap one though.

It just seems far too long to wait for hot water. Then if you need hot water again in a couple of minutes, the water starts running lukewarm after a few seconds before starting to heat up again.

 

[flameport]

Plate heat exchanger is probably scaled.
Easily resolved by removing and cleaning it.

 

[Toki]

Thanks everyone. The boiler was only installed 18 months ago and the water has always taken around this amount of time so I don't think it's that flameport. The boiler was serviced not long ago as well.