SYX66x Commissioning Guide
V1.10.3 300117
Page 25 of 61
6.4
Flow Economy Mode
Flow Economy will turn the heating off during an occupation period if the space temperature is at or above the
Space
Set point
and the current heating flow set point is within 7 degrees of the
Space Set point
. The Flow Economy mode
is evaluating if there is a real need for the heating to run. When the heating is switched off by day economy, pump
run-on will commence. The mode can be enabled or disabled in the Heating Set-up.
If Flow Economy is active and the space temperature drops more than 1 degree below Room day set point or the
calculated flow temperature is no longer within 7 degrees of the
Space Set point
then the heating will switch back
on.
6.5
Frost Protection
This is potentially a three stage system if the associated sensors are connected.
The first stage will bring on the heating pump and open the mixing valve (if connected) if the outside temperature
falls below the
Outside Frost
setting. The Outside sensor must be fitted during commissioning for this to be activated.
The Second stage is when the Heating return falls below the
Heating
Return Frost Limit
setting. The heating is
enabled in Day mode until the return temperature has risen by 35 degrees. A Heating Return Sensor must be fitted
during commissioning for this to be activated. Should the Heating Return Sensor be faulty then the Return Frost
Mode will be activated until the sensor is repaired.
The Third stage will bring on the pump and boiler(s) if the space or average of the two sensors falls below the
Space
Frost
setting, with flow temperature being fixed to the
Compensated Flow High
value to increase the space
temperature by 2 degrees as quickly as possible.
Frost protection operates during holidays, summer and when the Panel Switch setting is in the frost position.
6.6
Pump Run On
Pump run-on allows for the dissipation of heat from the boiler to the system by allowing the heating pump to continue
running after the end of any heating period. Pump run-on will operate at the end of any programmed time period,
extended time period, frost period or when the manual switch overrides the heating off. During the run-on period,
the compensated mixing valve (if fitted), is fully opened and the pump will run for a user selected period of time. At
the end of the run-on period, the valve will be closed to prevent gravity circulation during heating off periods.
The boiler(s) will be switched off for the duration of pump run-on. If not required, pump run-on can be disabled by
setting the run on time to 0 minutes.
6.7
Boiler Control
Boiler control allows for controlling 1 boiler, or 2 boilers in sequence. The lead boiler is rotated weekly on Sunday at
Midday unless rotation is disabled or only 1 boiler is in use. The boiler flow sensor must be fitted for the boilers to control
and operate. The controller uses the highest demand set point from the heating zone and/or HWS boiler linked
operation and modulates the boilers to maintain the required flow set point. A boiler offset is provided to allow for a
lift on boiler flow temperature to accommodate any system losses. This offset is ignored if the Compensated Flow
Sensor is not fitted. A minimum and maximum set point can also be programmed. The lead boiler will run when the
flow temperature is falling below the set point and will turn off when risen sufficiently above the set point. The boilers
are subject to a minimum run time and a minimum time between re-starts. When first starting, the lead and lag boiler
will start when required, if asked to run once more but inside a timer of 40 minutes of the previous firing period, the
boilers will not start until a 5 minute delay has passed. If outside the 40 minute period then the boilers will fire without
a start delay.
Additionally the controller offers a user selectable 0-10v output. This can be assigned to one function only but there
are a choice of three functions, two of these relate to boiler control options.
1. VT Valve
2. Boiler Set Point scaled over a 0-10v signal
3. Boiler % Demand 0-100% over 0-10v output this can be used direct to a condensing boiler or boilers or can
be sued to drive a step controller such as the BPRO range from SyxthSense.
