Glow-worm Clearly Solar Controller - Manual (Page 6)

6
System Functions
Solar gain
The installation engineer activates and configures the
solar gain function within the Fluropro installer menu.
The solar gain is determined from:
l
The difference of temperature between the collector flow
and return.
l
The flow rate setting of the flow rate adjuster.
l The operating time of the collector pump.
During installation the engineer sets the actual flow rate
and enters the setting into the solar control. The solar gain
is calculated and displayed by the solar control. The total
gain can be called up and reset in the installer menu.
Solar gain modulation
The rate of solar gain can be modulated to ensure the solar
heat at the bottom of the cylinder has sufficient time to
dissipate to the top of the cylinder. This maintains demand
for solar energy and prevents excessive on and off periods
that are inefficient.
The modulation is achieved by means of more frequent on
and off operations of the solar pump during solar demand.
The pump is switched on and off and the rate depends
upon the difference between the collector temperature
and lower cylinder sensor. When the activation difference
is reached, the function is started (if activated) with an
activation duration of 50 % - i.e., the pump is switched on
for 30 seconds and then switched off for 30 seconds. If the
difference in temperature increases, the activation duration
is prolonged (e.g., 45 sec. on, 15 sec. off). When the
difference in temperature decreases, the activation duration
is reduced (e.g., 20 sec. on, 40 sec. off). The period length
is always a minute.
Solar circuit protection function
If the solar heat exceeds the current heat requirement,
i.e. the cylinder is fully charged, the temperature in the
collector array can rise steeply.
To protect the solar circuit (solar pump, valves, etc.) from
overheating, if the protection temperature at the collector
sensor is exceeded, the collector pump is shut down and is
prevented from restarting even when there is a demand for
solar reheating. The solar pump is switched on again once
the system has cooled down. This function is performed
independently for each collector array. The control will
show “PROT” whilst this function is active.