Was the boiler actually firing continuously during this period or just occasionally?.
I would think that in built boiler frost protection only looks the boiler water temperature and circulates or/and fires the boiler as required just as it states, "If the temperature within the boiler falls below 8°C the pump will run to circulate water and prevent the system freezing. If the temperature within the boiler falls below 5°C the boiler will fire periodically, bringing the boiler temperature up to 12°C to avoid the possibility of the system freezing. This process will be repeated until such time that the boiler temperature does not drop below 5°C."
The key word there is circulates, if, somehow it opens a zone vale(s) then the temp should rise from 5C to 12C in a few minutes. if it doesn't open a zone valve then it has to circulate either through a external ABV or a internal bypass, again only a few minutes firing.
You stated in another thread that you have a external Frost Stat mounted in the garage alongside your boiler, it was suggested that you remove the frost stat's cover and see what its setpoint is??.
Should not have needed to post this thread but unfortunately have to... I had the new boiler (worcester bosch greenstar 30i)+ unvented cylinder installed by a gas engineer team recently. As something wrong with the system, I called the installation team, but they said the guy who actually...
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Thank you for your input!
The boiler started as the zone valve for hot water opened( pump started to run), so it fired continuously like when working normally ; then when, I think, the hot water in the cylinder is full, it fires like periodically---the Burner indicator (green light) was on for a minute and off for a minute.---I am not sure this is being like the manual states:"If the temperature within the boiler falls below 5°C the boiler will fire periodically".
When I read manual "the pump will start to run to circulate water", I thought it just circulate water but boiler not fire & heat water, but the fact is: when the pump started to run, the zone valve for hot water did open, and the boiler started to fire for hot water (then later boiler burner indicator came off and on periodically).
Actually, the manual states: "If the temperature within the boiler falls below 5°C the boiler will fire periodically, bringing the boiler temperature up to 12°C to avoid the possibility of the system freezing. This process will be repeated until such time that the boiler temperature does not drop below 5°C.""===but in my case, I checked the thermometer, the garage temperature was 6.6°C---this was below 8°C which means the pump will run to circulate water but as it was not below 5°C so why the boiler has fired like normal? ---Although later it was periodically(hot water in the cylinder was full I guess).
You mentioned the temp should rise from 5°C to 12°C in a few minutes----this is my biggest concern that: why my pump/boiler has been operating from 8:35am till 12:15pm(outside of timer setting time) only then the zone valve closed and boiler stopped?
It was 3hour and 40minutes! My understanding is just to fire boiler temperature from 5°C to 12°C should not take that long! So what happened yesterday morning 3hrs and 40mins pump/boiler all of sudden started to run---was that actually frost protection in operation???
Thank you for reading and connecting the other thread! Yes, I was not sure if the separate frost protection was in operation too, if that was, then will that conflict with the built-in one? Sadly, my gas engineer even could not answer me this, he does not know.....
And I dare not/not sure to open and test...