165/348
Siemens Building Technologies
Basic Documentation RVP540 / RVP550
CE1P2488en
HVAC Products
Description of the heating engineer settings
18.10.2002
Functions
4.111 Minimum temperature differential of the
wood-fired boiler
•
Pump Q10 of the wood-fired boiler operates only when there is a sufficient tem-
perature differential
To avoid unnecessary activation or delayed deactivation of the boiler pump, there must
be a minimum temperature differential between flow and return (minimum temperature
differential of the wood-fired boiler).
Setting range
Unit
Factory setting
- - - / 0...20
K
4
With small temperature differentials between boiler flow and return, the amount of heat
that can be delivered is too small. If the temperature differential of the wood-fired boiler
falls below the minimum, the boiler pump will be deactivated on completion of the pump
overrun time (operating line 372), even if it should still be running according to the crite-
ria of operating lines 370 and 371.
“- - -“ will deactivate the function.
The diagram below shows a possible progression of the temperature of the wood-fired
boiler and the relevant switching states of the boiler pump (Q10):
Also refer to the graph on operating line 370.
[°C]
23
92Z0
7
t [s]
ON
OFF
ON
OFF
Q10
t [s]
TV
TR
TV
Actual value B22 of temperature of the wood-fired boiler
T
R
Return temperature B72
Q10
Pump of the wood-fired boiler
370
Minimum temperature of the wood-fired boiler for release of the pump
371
Switching differential for “Minimum temperature of the wood-fired boiler for release of the pump”
372 Pump
overrun
time
380
EXP
Minimum limitation of the return temperature of wood-fired boilers
– – –
Minimum temperature differential of the wood-fired boiler OFF
Benefit
Description
Setting
Effect
Special displays