Valliant Ecomax 828E - anti cycling mode S8

[bjarvis]

I think I may have a problem with my heating operation - my heating system (4 rooms, 4 radiators) seems to be taking longer than usual to heat up. So starting with the controller thermostat reading 13C in the morning it takes 2 hours to reach the thermostat set temp of 19.5C. On observing the boiler during this time it appears to be switching from S4 (boiler firing) to S8 (anti-cycling mode) once it has initially gotten to its flow temp of 88C (this takes about 17 mins of continuous boiler firing). After reaching 88C it switches to S8 for 5 mins. During this 5 mins at S8 the flow temp drops back to about 66C. Is this all normal thus far?

After that it is back to S4 and the boiler fires again for about 5 mins until 88C is reached again. It then cycles like this i.e. 5 mins on, 5 mins off until the thermostat set temp of 19.5C in my flat is finally reached (2 hrs). It then goes to S7 (pump over run) for 5 mins, before S0 (no heat demand) as expected. In all it makes this S4/S8 cycle about a dozen times. Again is this normal? Or does this indicate a problem with my pump?

Note that the controller is calling for heat during this entire 2 hrs (boiler symbol on).

Hot water seems fine although again seems to be taking longer these days than usual to get hot in the morning (45 - 60 secs) - not sure if this is related?

Grateful for any advice anyone can offer, or further tests I can make.

Thanks

Barry

 

[cross thread]

boiler sounds ok,do the rads get hot ?sounds like they may be undersized for the rooms,most systems are designed to heat a room with a minus 1 outside temp,it has been a lot lower so it may be that