Tank Loading Switch-Over - Honeywell SDC Service Manual

SDC / DHC
Solid-fuel boiler
maximum temperature
Solid-fuel boiler buffer
tank switch-on
differential (switching
differential ON)
Solid-fuel boiler buffer
tank switch-off
differential (switching
differential OFF)
Heat generator
cycle disable
Anti-blocking function
7.3.7
EN2H-0221GE51 R0812
If the temperature in the solid fuel boiler rises above the set
maximum temperature limit, the solid-fuel loading pump is forced
limit to switch on. The excess heat is then dissipated into the
preselected circuits (see "Buffer Tank" menu). This forced
dissipation will be cancelled and the temperature differential
control enabled when the solid-fuel boiler temperature
undershoots the maximum limit by more than 10 K.
If the temperature in the solid-fuel boiler rises above the current
temperature in the buffer tank by at least the set amount, the
solid-fuel loading pump is switched on and the buffer tank is
loaded.
Prerequisite:
The temperature of the solid-fuel boiler is at least 10 K over the
minimum temperature limit.
The min. set value is 3 K above the switch-off differential.
If the differential between the solid-fuel boiler and buffer tank
temperatures is less than the set amount, the solid-fuel loading
pump is switched off and loading is interrupted. The max. set
value is constantly 3 K below the selected activation difference in
order to prevent rear discharging of the buffer tank.
Heat generator solid-fuel cycle disable
The solid-fuel cycle disable serves to prevent frequent switching
between loading through the solid-fuel boiler and loading through
a conventional oil/gas heat generator.
After the solid-fuel loading pump has been switched off, the set
time must pass before loading of the buffer tank is continued
through the conventional heat generator.
This is an automatic function of the controller. If the solar loading
pump was switched off longer than 24 hours, it is operated for
approx. 20 seconds to prevent blocking via corrosion.

Tank loading switch-over

In systems that have both an external hot-water tank and a buffer
tank, a diverter valve can be used to switch between loading the
hot-water tank and loading the buffer tank from solar power
system. This allows economical and effective use of solar power
Hydraulic Components
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