Promatic WDC Series, Manual

Page: 58 / 176

Service setting manual 58
ENG
LEGEND:
A - liquid fuel boiler
B - solid fuel boiler or heat accumulator
PT - switchover temperature
Operation diagram for hydraulic schemes with two heat sources
Switchover from liquid fuel boiler (A) to solid fuel boiler or heat accumulator (B)
Heat source A is deactivated when temperature of heat source B exceeds switchover tem-
perature PT (point 1).
For switchover temperature PT the highest of below temperatures is taken:
- minimum temperature of heat source B, increased for 10 °C,
- the highest calculated stand pipe temperature of both mixing circuits (upper limit of this
temperature is set with parameter S5.2, reduced for 5 °C),
- measured temperature of d. h. w., increased for 10 °C (upper limit of this temperature is set
with parameter S4.8).
Diverting-valve switches to heat source B (point 2) when temperature of heat source B is
equalized with temperature of heat source A.
Switchover from solid fuel boiler or heat accumulator (B) to liquid fuel boiler (A)
Timer for activation of heat source starts to run when temperature of heat source B drops
below switchover temperature PT (point 3) and cannot cover heating demands. Temperature
difference between calculated heating temperature and temperature of heat source B leads
to earlier activations of heat source A and vice versa. Setting of parameter S5.15 also affects
on switchover delays (see page 46).
Heat source A (point 4) is activated again after the delay time expires.
Diverting-valve switches to heat source A (point 5) when temperature of heat source A for 6 °
C exceeds temperature of heat source B.