The Towerchron QE2 is an electronic programmer which provides timed control of heating and hot water for a domestic gas, oil or solid fuel fired heating system.

The programmer is wall mounted; for fixed wiring, and can be fitted over a plaster depth wiring box if required.

Control can be in two forms: heating and hot water independently, for fully pumped systems. Or, heating + hot water / hot water only for gravity primary (hot water) systems. These two control modes are selected by setting a slide switch on the back of the programmer at the time of installation. The control mode can be changed if the system is upgraded from gravity primary to fully pumped.

The outputs of the QE2 are 240 volt mains, due to internal linking. The QE2 is not suitable for SPECIFICATIONS requiring volt-free switching. The outputs are rated at 5 amps resistive; 2 amps inductive. A built-in rechargeable nickel-cadmium battery provides 150 hour back-up for the current time display and programme memory, in the event of mains failure.

The unit can control on a 24 hour and/or 7 day basis. For ease of commissioning, it has an inbuilt programme which is enabled by moving the slide switch to "run preset programme".

If the user wishes to set his/her own programme, programming capacity is as follows:

Each channel has 28 programme spaces (14 on, 14 off) for switching instructions. Each programme space can be set for any of the following day groups: MON-SUN, MON-SAT, MON-FRI, SAT-SUN, or any individual day. A programme space used for any day group will operate on all the days selected, but it still uses only one programme space. If every programme space were used for all seven days of the week, the unit would carry out 196 switching operations, per channel, per week.

If the heating and hot water are to switch at the same times, there is no need to re-programme the hot water channel separately. When programming heating instructions,

the copy button can be pressed to store the same timed instruction for hot water as well.

Once the unit is set with current time & day, and (if required) a timed programme sequence, the slide switch is put into "Run preset programme" or "Run own programme" position, and the l.c.d. (liquid crystal display) will show the following information:

• Current time (A.M. / P.M. 12 hour clock) and day. A ‘flag’ is displayed under weekdays printed on the case.
• Winter or Summer (GMT or BST)
• Manually selected condition of each channel - timed; boost; adv(ance); const(ant); off.
• Actual state of each channel - ON or OFF
• In addition, two orange l.e.d.’s (light emitting diode) under the display, corresponding to heating and hot water, will be lit if the channel is on. The l.e.d.’s will not function unless mains power is connected. The l.c.d will function with mains connected, and on the back-up battery.

The manual selections available are:

• Tmd - Timed - switching occurs as programmed - either inbuilt or own programme, whichever is selected.
• Boost - the channel is switched on for one hour, it will then revert to the timed control according to the programming. This is a self-resetting selection.
• Adv - Advance - the channel is switched on or off early - advance changes the state of the switch from the current timed state. This is a self-resetting selection.
• Const - Constant (ON) - this fixes the channel in the on condition. It will remain in this condition permanently until the manual button is used to change to another condition.
• Off - this fixes the channel in the off condition. It will remain in this condition permanently until the manual button is used to change to another condition.