Return Lift; Combination With Storage Tank; Chimney Connection/Chimney System - Froling SP Dual compact Operating Instructions Manual

Safety
Design information

2.7.5 Return lift

2.7.6 Combination with storage tank

2.7.7 Chimney connection/chimney system

Operating Instructions SP Dual compact | B1500016_en
Pump-controlled pressure maintenance
A pump-controlled pressure maintenance unit essentially consists of a pressure-
maintenance pump, relief valve and an unpressurised receiving tank. The valve
releases hot water into the receiving tank if the pressure is too high. If the pressure
drops below a preset value, the pump draws water from the receiving tank and feeds it
back into the heating system. Pump-controlled pressure maintenance systems with
open expansion tanks (e.g. without a diaphragm) introduce ambient oxygen via the
surface of the water, exposing the connected system components to the risk of
corrosion. These systems offer no oxygen removal for the purposes of corrosion
control as required by VDI 2035 and in the interests of corrosion protection should not
be used.
If the hot water return is below the minimum return temperature, some of the hot water
outfeed will be mixed in.
CAUTION
Risk of dropping below dew point/condensation formation if operated without
return temperature control.
Condensation water forms an aggressive condensate when combined with
combustion residue, leading to damage to the boiler.
Take the following precautions:
❒ Regulations stipulate the use of a return temperature control.
➥ The minimum return temperature is 60 °C. We recommend fitting some
sort of control device (e.g. thermometer).
You can find more detailed information about storage tank design in the boiler
assembly instructions.
NOTICE! See "Design Information" section in the assembly instructions SP Dual
compact
EN 303-5 specifies that the entire flue gas system must be designed to prevent,
wherever possible, damage caused by seepage, insufficient feed pressure and
condensation. Please note in this respect that flue gas temperatures lower than 160K
above room temperature can occur in the permitted operating range of the boiler.
NOTICE! Please see the technical data contained in the assembly instructions for
further information about standards and regulations as well as the flue gas
temperatures when clean and the other flue gas values!
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