M thermal Mono 
202005                                                                                                                                                                                                                  77 
Part 3 - Installation and Field Settings 
  That in case of an installation with a domestic hot water tank, only the use of propylene glycol is allowed. In other 
installations the use of ethylene glycol is fine. 
  That no automotive glycol is used because their corrosion inhibitors have a limited lifetime and contain silicates that 
can foul or plug the system; 
  That galvanized piping is not used in glycol systems since it may lead to the precipitation of certain elements in the 
glycol’s corrosion inhibitor; 
  To ensure that the glycol is compatible with the materials used in the system. 
 
3.5  Water Flow Switch 
Water may enter into the flow switch and  cannot be drained out  and may 
freeze  when  the  temperature  is  low  enough.  The  flow  switch  should  be 
removed and dried, then can be reinstalled in the unit. 
 
  Counterclockwise rotation, remove the water flow switch. 
  Drying the water flow switch completely. 
 
 
 
 
 
3.6  Adding Water 
  Connect the water supply to the fill valve and open the valve. 
  Make  sure  the  automatic  air  purge  valve  is  open  (at  least  2  turns). 
Refer to Figure 3-3.3. 
  Fill  with  water  until  the  manometer  indicates  a  pressure  of 
approximately 2.0 bars. Remove air in the circuit as much as possible 
using  the  air  purge  valve.  Air  in  the  water  circuit  could  lead  to 
malfunction of the backup electric heater. 
 
 
 
 
3.7  Water Piping Insulation 
The  complete  water  circuit  including  all  piping,  water  piping  must  be  insulated  to prevent  condensation  during cooling 
operation and reduction of the heating and cooling capacity as well as prevention of freezing of the outside water piping 
during winter. The insulation material should at least of B1 fire resistance rating and complies with all applicable legislation. 
The thickness of the sealing materials must be at least 13mm with thermal conductivity 0.039W/mK in order to prevent 
freezing on the outside water piping. If the outdoor ambient temperature is higher than 30°C and the humidity is higher 
than RH 80%, the thickness of the sealing materials should be at least 20mm in order to avoid condensation on the surface 
of the seal. 
   
Figure 3-3.2: Water flow switch   
Figure 3-3.3: Air purge valve   
Do not fastenthe black plastic
cover on the vent valve at the
topside of the unit when the
system is running. Open air
purgevalve,turnanticlockWise
atleast2 fullturnstoreleaseair
from the system.