Spirax Sarco LC2650 - Page 22

IM-P402-128 EMM Issue 7
22
Three element control
Under certain conditions where the boiler feedwater pressure varies considerably, perhaps
due to other boilers drawing water, three-element control is used. A water flowmeter is added
to compensate for variations in flow due to pressure variations.
Fig. 11 Three element control
OK
LC2650
100
50
0
%
SP
PV
AL
Steam meter
Level probe
Motorised
KE / EL valve or
Pneumatic valve
Water
flowmeter