Description Of Locon - Honeywell S4965 Series Product Handbook

DESCRIPTION OF LOCON

LOCON means Load Control.
LOCON is able to measure and control the load of a gas fired
heating appliance.
LOCON is suitable for atmospheric (with or without fan)
modulating boilers.
Features are:
No or minimum adjustments of VK4105G2000 valve at the
production of the combiboiler.
Improvement of the DHW temperature control performance.
Easy swap from LPG to natural gas
temp.
setpoint
temp.
control
+
-
REMARK: Electrode postition and choice is important.
In cooperation with Polidoro, Honeywell has made
a standard solution.
New applications require Honeywell approval.
PI control
+
-
NTC temperature sensor information
Fig. 6. LOCON control flow diagram
I (P )
flame
0
I
flame-max
P
0 max
I
flame (P0) ign
I
flame (P0) max
B
min
Fig. 7. Ionisation flame current versus the boiler load
LOCON is based on the phenomena that the ionisation flame
current in an atmospheric boiler is almost linear with burner
load. (see fig. 7)
Using this property the critical minimum pressure and ignition
pressure adjustment can be avoided.
If a throttle is used for maximum pressure regulation no
adjustment is needed.
Only injectors have to be changed if LPG is needed.
( see fig. 6.for the control flow diagram )
LOCON loop
Valve current control
ionisation current
throttle-adjustment
at P
i-nom
B B
ign max
Boilerload
9
Burner
Heat exchanger
EN2R-9053 0408R11-NE