New Vaillant ecoFIT pure 625 System Boiler - keeps firing up a few times - is this normal?

JDSurrey

I've recently had a new Vaillant ecoFIT pure 625 System Boiler installed and want to see if it's normal for these boilers to fire up for a couple of mins a few times every hour, even though the heating and hot water is not timed to be on? The flame symbol comes on and the radiator symbol flashes for a couple of mins, then the egg timer symbol flashes for about 5 mins and then it goes quiet - this happens a few times an hour and through the night.  
Just want to check this is normal as it's the first time I've had a Vaillant and a system boiler - as I've never had this happen with a regular Potterton boiler this replaced.
Many thanks for your comments!  

daveyjp

Its not normal to call for heat when its not set to, what type of timer and thermostat is it connected to?

johnferrier

could be the pre-heat function for the hot water? you can turn this off i believe .

Browntoa

As above , if a combi boiler it's hot water pre heat

JDSurrey

daveyjp said:

Its not normal to call for heat when its not set to, what type of timer and thermostat is it connected to?

Thanks -
The Upstairs radiators are operated by a Honeywell CM51 Timer/Thermostat
The Downstairs underfloor heating is operated by a Heatmiser UH8-RF linked to Room Thermostats
The Hot Water is controlled by a Horstmann Channelplus H17XL Timer 

JDSurrey

johnferrier said:

could be the pre-heat function for the hot water? you can turn this off i believe .

The hot water is set to off (something done by the installers),Whilst the heating temp is 60 

daveyjp

As you have UFH you may have a faulty room stat.  My parents have UFH in their bungalow and all the stats have been replaced over the years.

I noticed the last one as there was a call for heat even though it was summer.  We found the faulty stat by turning them off one at a time until the boiler stopped cycling.  As you have a mixed UFH and rad system start by turning all the UFH stats off.

oniongirl

I've just been reading our valiant user manual. Not sure it's the same as yours, but constant rad symbol means "heating mode" and flashing means "anti cycling mode"

JDSurrey

daveyjp said:

As you have UFH you may have a faulty room stat.  My parents have UFH in their bungalow and all the stats have been replaced over the years.

I noticed the last one as there was a call for heat even though it was summer.  We found the faulty stat by turning them off one at a time until the boiler stopped cycling.  As you have a mixed UFH and rad system start by turning all the UFH stats off.

Thanks, I’ve only been in the house for a few months, but over that time I can see that the UFH room stats communicate with a UFH master box which has a light for each room which comes on when there’s a heating requirement and then the boiler light on the UFH master box also comes on  (which I assume is indicating that’s it’s requesting heating from the boiler).

JDSurrey

oniongirl said:

I've just been reading our valiant user manual. Not sure it's the same as yours, but constant rad symbol means "heating mode" and flashing means "anti cycling mode"

Thank you. My manual says the egg timer is the burner anti cycle mode is active - which it explains is to “avoid frequent switching on and off”. 

I’m trying to understand if it’s normal for Vaillant boilers to fire up for a couple of minutes and then go into anti cycle mode for 5 mins - a few times every hour, whilst I know all the thermostats and timers are switched off (ie should not be asking the boiler for heat or hot water)

oniongirl

I wish you luck. Mine is confusing me as well as it keeps saying things are requesting heat and hot water when the programmer says they aren't. Mysterious indeed.