1
Chrono-proportional Control
Traditional ON/OFF room thermostats control room temperature by switching
the circulating pump, and usually the boiler, on and off.
Because of the thermal inertia of the heating equipment and the relatively
large switching differentiials of on/off devices large space temperature
variations often occur, resulting in poor comfort conditions.
Chrono-proportional Control as implemented in the TP75-RF overcomes the
problem by ensuring that the boiler fires regularly for periods calculated to
maintain radiator temperature without overheating and to prevent the radiator
temperature falling to a level which can allow down draughts from cold
surfaces, e.g. windows, to cause discomfort.
The control logic works on a proportional band of 4°F which assumes that the
boiler will operate at full load when the sensed space temperature is 4°F or
more lower than the programmed set point.
The following graph shows the relative on/off periods per cycle against
variances in deviation from the set point.
TP75
TP75
Control Features
The TP75-RF is a wireless communication version of the standard hardwired
TP75 programmable thermostat. The TP75-RF, which contains a transmitter,
works in conjunction with an RX receiver module which can be located up to
30m from the thermostat.
The TP75-RF Series of programmable room thermostats incorporate two
special features that can be enabled at the time of installation - Optimum
Start Control and Chrono-proportional Control.
Optimum Start Control (OSC)
With this enabled the event 1 control temperature, (which would normally be
an increase from an overnight set-back temperature), may be programmed
to be achieved by a desired time. The heating plant will be switched on earlier
than the programmed time by a period related to the start-up curve selected
and the space temperature sensed at the beginning of the selected start-up
period. The diagram below indicates the switch on periods for the available
start-up curves.
If OSC is disabled then the unit will operate as a conventional room
thermostat, switching on the heating plant at the event 1 time with the event
1 temperature being achieved in a time related to the prevailing conditions.
Installation & Commissioning Guide
Battery Compartment Flap lowered
Specification
Control temp. range
: 41°F to 85°F (5°C to 30°C)
Power Supply
: 2 x AA size alkaline batteries
Transmission Frequency
: 433.92 MHz
Range
: 30m typical
Time Keeping Accuracy
: ± 1 minute/month
Low Battery Warning
: 15 days duration
Memory Retention with
Batteries Removed
: one minute
Enclosure Rating
: IP30
Maximum Ambient Temp
: 113°F
Designed to British Standard
: BS EN60730-2-9
Overall Dimensions
Unit
: Width: 136mm
Height: 88mm
Depth:
32mm
Emission Designator
: 2K02D
FCC Identifier
: P07 TP75RF
FCC Rules
: 15°C
Programmable Room Thermostat
with Wireless Communication
TP75-RF with integral sensor
90
min
30
min
60
min
Selecting 0
effectively
disables
the OSC
function.
Desired Event 1
temperature
Degrees below the desired temperature at
the beginning of the Optimum Start Period
-3.6°F
(-2°C)
120
min
-1.8°F
(-1°C)
-5.4°F
(-3°C)
-7.2°F
(-4°C)
Event 1
time(0)
Available Start-up Periods
With a -3.6°F (-2°C) deviation and the 30 min. curve selected the
heating system will switch on 15 min. before the Event 1 time.
