Honeywell DHC, Service Manual

Page: 214 / 262

Hydraulic Components SDC / DHC
214 EN2H-0221GE51 R0812
7.3.6.3 Solid fuel function
This function can only be called up, if a configurable switching
output was occupied with a solid fuel loading pump.
The following sensors can be used for control:
• SFS for the solid fuel boiler sensor
The connection occurs automatically depending on the
assignment of the output to VI1 or VI2.
• SFS for the solid fuel buffer sensor (optional)
The connection occurs to variable input 1 – variable input 3
depending on the assignment to an available variable input.
• If no solid fuel buffer sensor is connected, the collector
tank/buffer sensor value (dedicated sensor input) is accepted
as the buffer sensor. In this way, the collector tank/buffer
sensor input can be used as a sensor input for several
uncontrolled heat generators (e.g. solar or solid-fuel).
ATTENTION
Note the sensor position and stratification conditions.
A forced switch-on will be initiated for the solid fuel loading pump
if a solid-fuel boiler sensor is defective.
The solid-fuel function allows the integration of solid-fuel boilers
(usually in combination with a buffer tank) into the system to
support heating. Under this function the solid fuel loading pump
can be controlled through various switching conditions as
described in the following.
If the temperature in the solid-fuel boiler rises 10 K above the set
value, the solid-fuel loading pump is enabled.
If the temperature in the solid-fuel boiler undershoots the
minimum boiler temperature, the solid-fuel loading pump is
switched off and loading is interrupted.
NOTE
Function
Solid-fuel boiler
minimum temperature
limit