Hi wondering if anybody can help we have a Biasi m90f 28s combi which is running fine apart from a problem that has developed. when the water in the heating system reaches its high temp setting (about 65c) it shuts the flame continues circulating as it should. Then after about 20 seconds flames up again for about 20 then flames down again and keeps repeating this until the thermostat stops demanding heat. it has always cycled but normally loses 8 to 10 degrees of internal water temp before flaming again until it reaches system cut off usually a couple of minutes at least
it does not do this when it starts in the morning it run continuously until it reaches the boiler set point nor when the stat calls for top up heat throughout the day only when the water in the heating system water reaches its set point. all rads are nice and hot, no cold spots in system, no air in system and the DHW works normally. all indicator lights show normal.
i hope i have described the fault clearly but it has me stumped and concerned the rapid frequent recycling could cause damage
it does not do this when it starts in the morning it run continuously until it reaches the boiler set point nor when the stat calls for top up heat throughout the day only when the water in the heating system water reaches its set point. all rads are nice and hot, no cold spots in system, no air in system and the DHW works normally. all indicator lights show normal.
i hope i have described the fault clearly but it has me stumped and concerned the rapid frequent recycling could cause damage
