Heatrae Sadia HI-MAX INSTANT ID 5-60 Installation, Operation And Maintenance Manual page 15

Figure 17: HI-MAX INSTANT ID Indirect Units - Hydraulic Schematic -
Radiator System
1
2
3
1 District Return
2 District Flow
3 Cold Water Services
The programmable room thermostat should be
installed in the coldest room in the property where
the only heat source is a radiator without TRV. The
radiator should be fi tted with lock shield valves to
avoid it being inadvertently isolated. It will then act
as a system bypass and heat dissipater for the system
when there is a small demand on the system.

The hydraulic schematics within this document are for guidance only and do not constitute system design.
Some components may not be detailed and connection positions have been moved for clarity purposes.
For clarifi cation of the position of the connections refer to Figure 11 on page 10.

When installing the HIU avoid pipe runs that promote gravitation. Where pipes have to be installed
directly up from a heat source consider piping in an anti-gravity loop (ie, a section of pipe that goes down
before it rises up).

Radiator systems should be designed to operate at low system temperatures in order to keep district
return temperatures to a minimum.
Heating Zone 2
Heating Zone 1
Dynamic balancing valve at the end of each branch to
maintain primary fl ow pipe temperatures during periods
of no demand. Alternatively enable the pulsed fl ow
bypass function on the HI-MAX INSTANT.
FBP
HM1
HM2
HM
P
S2 S3
P
P1
A
S1
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