This wall-mounted line voltage frost thermostat from Honeywell can protect your building & pipework from the effects of frost, by heating when reduced temperatures are met.

The frost thermostat must be located in the coldest part of the house, but where it can respond to a rise in temperature as a result of switching on the boiler. If situated in an outhouse or garage, it is strongly recommended that a pipe thermostat should also be used to switch off the boiler when the return temperature reaches a predetermined level, unless the location will ensure that the T4360A will pick up a temperature rise. It must only be located inside a dwelling or outhouse, and not directly exposed to the weather. A frost thermostat should not be fitted outdoors.