Xylem MOH2 Multi zone mixing module (obsolete) - Manual (Page 16)

16
Installation and operation manual MOH2
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Technical data
Maximum system pressure 145 PSI (10 bar )
Circulator see diagram
Floor heating loop
Maximum temperature
140°F (60°C)
Feed connection 1" female thread/flange for segmented
plastic manifold
Return connection...
Boiler loop
Maximum temperature
220°F (105°C)
Feed connection 3/4" female thread in ball valve
Return connection...
Heating performance of MOH2 module
• The heating performance of the MOH2 module is dependent on
- Hydraulic characteristic of the floor heating system
- Differential pressure between boiler feed and return
- Temperature difference between boiler loop and floor heating loop
• Example
- Floor heating feed temperature 50°C [120°F]
- Floor heating return temperature 42°C [108°F]
- Pressure drop in floor heating loops including manifolds 23 kPa [7.5ft]
- The pump curve yields for this differential pressure a flow rate of the
integrated circulator of 1.7 m 3 /h [7.48 US GPM].
- This means that the MOH2 module can distribute 15.8 kW. in the
floor heating system.
- With an assumed delta T in the boiler loop of 25 K. [45°F], the boiler
loop needs to furnish 0.5 m 3 /h [2.2 US GPM] at peak heat demand
- Since the boiler return temperature is equal to or larger than the
floor heating return temperature, the minimum boiler feed temperature
at peak heat demand is 67°C [150°F]
- The diagram for the presetting knob which adjusts the boiler side
differential pressure shows that for this flow rate, the differential
pressure in the boiler loop needs to be at least 20 kPa [6.6 ft].