Drayton HTS3 Cylinder Thermostat Installation instruction


Drayton HTS3 Cylinder Thermostat 


What is a cylinder thermostat?

an explanation for householders
A cylinder thermostat switches on and off the heat supply from the boiler to the hot-water cylinder. It works by sensing the temperature of the water inside the cylinder, switching on the water heating when the temperature falls below the thermostat setting, and switching it off once this set temperature has been reached.
Turning a cylinder thermostat to a higher setting will not make the water heat up any faster. How quickly the water heats up depends on the design of the heating system, for example, the size of boiler and the heat exchanger inside the cylinder.
The water heating will not work if a time switch or programmer has switched it off. And the cylinder thermostat will not always switch the boiler off, because the boiler sometimes needs to heat the radiators.
Cylinder thermostats are usually fitted between one quarter and one third of the way up the cylinder. The cylinder thermostat will have a temperature scale marked on it, and it should be set at between 60C and 65C, then left to do its job. This temperature is high enough to kill off harmful bacteria in the water, but raising the temperature of the stored hot water any higher will result in wasted energy and increase the risk of scalding.
If you have a boiler control thermostat, it should always be set to a higher temperature than that of the cylinder thermostat. In most boilers, a single boiler thermostat controls the temperature of water sent to both the cylinder and radiators, although in some there are two separate boiler thermostats.Drayton-HTS3-Cylinder-Thermostat-1

Cylinder thermostats


Technical Data

  • Setting Range 50° – 80°C
  • Differential 8°C approx.
  • Switch rating 3 (1) A 230V ac
  • Switch type SPDT
  • Rated impulse voltage 2.5kV
  • Earth Double insulated not required
  • Connections
    • C – common
    • 1 – call
    • 2 – satisfied
  • Fixing Plastic-coated spring wire with hook and eyelet.
  • Pollution Degree 2
  • Ball pressure 110ºC
  • Test Temperature I = 1% (Acc. EU
  • Energy Class
    • 811/2013, 812/2013,
    • 813/2013, 814/2013)

Conforms to the essential requirements of the following directives:

  • 2014/30/EU – Electromagnetic Compatibility Directive
  • 2014/35/EU – Low Voltage Directive
  • 2011/65/EU – Restriction of the Use of Certain Hazardous Substances (RoHS)

Positioning the HTS3
The HTS3 should be installed approximately one third of the way up the hot water cylinder, and at the front for ease of access.With pre-insulated cylinders, mark the position and size, and remove just enough insulation to allow the HTS3 to fit against the metal of the cylinder in the recess formed.


Wiring Connections
From the wiring centre or junction box, run sufficient 3-core electrical connecting cable to reach the HTS3 installation position without being under tension.
Remove the HTS3 cover by undoing the central retaining screw. Make wiring connections in accordance with the diagram below and the manufacturers instructions for associated equipment such as motorised valves, boiler, programmers etc. Replace and secure the cover.
The HTS3 is double insulated and no Earth connection is necessary.The circuit should be protected with a 3A fuse.


Fixing to the Cylinder
The base of the HTS3 should be held in good contact with the metal of the hot water cylinder.
The plastic covered spring fixing cable should be cut to an unstretched length of approximately 2 1/2” – 3” less than the circumference of the cylinder and the hook and eyelet screwed into the ends. Stretch the cable round the cylinder, above the insulation, and position it in the groove across the front of the HTS3. Engage the hook and eyelet.


Disconnect mains supply before fitting or removing the cover.
A switch having contact separation of at least 3mm in all poles must be incorporated in the fixed wiring as a means of providing full disconnection of the mains supply.


Download manual: Drayton HTS3 Cylinder Thermostat nstallation instruction


Drayton HTS3 Cylinder Thermostat Installation instruction


Leave a Reply

Your email address will not be published. Required fields are marked *