frost protection in loft, frost and pipe stat alternatives

18 Sep 2009
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United Kingdom
I currently have my gloworm boiler in the loft and have frost protection using a frost stat and a pipe stat on return, the air temp in the loft when its really cold never gets above the minimum of the frost stat (3 deg), so it acts almost as a continually on switch, the system works but I believe this leads to the boiler cycling more than needed, even though the temp in the boiler is still well above freezing.
Can I improve the current set up of frost stat and pipe stat
Could I do the same thing with 2 pipe stats on the flow and return so that the temp of the water in the boiler is what switches the boiler on and off and not the air temp in the loft.
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The Air stat should be wired in SERIES with the pipe stat, which should be fixed to the heating return pipe, the air stat shouold be set a 5'c the pipe stat at 20'c, wired this way the boiler will only fire when BOTH STATS are calling, it sounds like you have not wired in series meaning that the boiler fires whichever stat calls - which will be the air stat MOST OF THE TIME!!

Rewire your stats correctly, and the frost protection will be as economical as possible, remember that a few quid spent of gas for frost protection, it will be far cheaper than a burst pipe!!! ;)
I believe I have the stats connected in series but as I said due to the low air temp in loft the frost stat is permanently made, due to this the boiler cycling on and off is controlled by the pipe stat. Not sure if this is correct but if the pipe stat is set to 20c, then when it reaches that temp it switches off, until the water temp drops to under 20c, say 15c then the boiler switches on again as the frost stat is permanently made.
if im right in my assumptions above then the boiler is cycling on and off by using a difference in the water temp only, as sensed by the pipe stat ,what else could i try apart from moving the frost stat really close to the boiler so it picks up the heat from the casing.
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That is how the frost protection should operate
if the boiler does not fire to maintain this you risk a frozen pipe and lots of damage to property which if your insurer finds out is due to in-adequate frost protection, will be reluctant to pay out for any damage caused ;)

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