Adarad DUNATECH 2012, Installation And User Manual

Hydraulic circuit

Open vented hydraulic circuit
Dunatech boilers are preferred to be installed in a hydraulic circuit with an open type expansion tank in accordance 
with the following schemes. The circulation pump in the circuit should be installed on the return line to boiler in order to 
prevent the system from excessive thermal stresses and overheating during electricty cuts off:

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Open type expansion tank must be installed at the heighest level of whole hydraulic system.  No globe valves must be
installed on delivery and return safety lines between boiler and expansion tank. Safety lines should be attached to inlet 
and outlet lines of boiler at points as close as possible to boiler, using the shortest possible vertical way between
expansion tank and boiler.

If "h" distance in above scheme can not be arranged within the construction of present system, the circulation pump  
must be installed on delivery line from boiler. "h" distance refers to the head pressure of circulation pump at operated 
speed. If "h" distance can not be arranged in a system with circulation pump on return line, there will be air suction 
from radiators at the highest level of system. In this case,the other scheme where pump is installed on the delivery 
line must be referred.

A hydrometer must be installed on the delivery line to monitor the pressure level and to check if there is any leakage. 
The hydrometer should be purchased separately, and should be installed at the same level with the boiler outlet.

A by-pass line should be installed between inlet and outlet connections of circulation pump in order to allow maximum 
water delivery when circulation pump is switched off and there is fuel fired in boiler, particularly during sudden electricty
cuts off.

The optional safety heat exchanger kit is highly recommended to be used with the boiler, even in the case

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The optional safety heat exchanger kit is highly recommended to be used with the boiler, even in the case
of open vented systems to protect the boiler and the whole heating circuit against excessive heat 
accumulation. For installation of this kit, please refer to the next section

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