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The Polytank 15 Gallon (68 Litre) Cold Water Storage Tank (24"x12"x20") comes with the following fits kit:
The Honeywell CM921 Wireless Programmable Thermostat is a wireless thermostat providing control over the time and temperature of the domestic central heating system. The CM921 Programmable Thermostat allows the user to programme different time and temperature requirements for the day but where the heating needs to be the same from day to day. The CM921 Wireless Programmable Thermostat has a slim modern design that is complemented with a large LCD screen with Line of Text display and one function button for quick and simple operation and programming.
The Honeywell CM921 Wireless Programmable Thermostat can be used to control the heating circuit in a sundial S or Y plan and is well suited to control a combi boiler installation or additional heating zones in an S plan plus system.
In a closed central heating system water cannot be compressed so any increase in the volume, created by an increase in temperature, needs to be accomodated. This is done with the use of an expansion vessel, when the water in the system is cold the pre-charge pressure of the system forces a diaphram in the expansion vessel against the tank towards the inlet. As the temperature increases the expanding water volume pushes against the diaphragm creating additional volume for the water to enter the expansion vessel. As the temperature decreases the pre-charge pressure forces the water from the expansion vessel back into the central heating system. This maintains a constant pressure within the central heating system and helps to reduce energy and water consumption.