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4 Dimensioning and planning 

99640x6xx-mub-de – V08 

2016/07 

4

 

Dimensioning and planning 

The FriwaMidi and FriwaMaxi are domestic hot water modules which heat potable  
water operating on the principle of a flow-type water heater. 

The FriwaMidi and FriwaMaxi can only work flawlessly if the installation meets certain 
requirements. Please take some time to plan the installation. 

 

 

 

WARNING 

Danger of scalding due to hot water! 

Undesirable circulation of water in the primary circuit can cause the exit of  
water of up to 90 °C at the withdrawal point. 

 

External pumps must not be installed between the domestic hot water 

module and the buffer tank. 

 

The domestic hot water module must not be connected to a distribution 
manifold. 

Mounting example 

 

 

FriwaMidi with optional circulation set (item no. 640412) and with optional return distribution 
(FriwaMidi: item no. 640423, FriwaMaxi: item no. 640424) 

Safety group  

according to DIN 1988 

Summary of Contents for FriwaMaxi-DN 25

Page 1: ...1 D 31789 Hameln Germany Phone 49 5151 9856 0 Fax 49 5151 9856 98 E mail info paw eu Web www paw eu 2016 07 99640x6xx mub de V08 1 Installation and Operation Instructions Domestic hot water modules FriwaMidi DN 20 FriwaMaxi DN 25 ...

Page 2: ...alist 21 9 Spare parts specialist 22 9 1 Spare parts control and insulation FriwaMidi 6405640 6405641 and FriwaMaxi 6406662 6406663 22 9 2 Spare parts hydraulics FriwaMidi without circulation 6405640 with circulation 6405641 23 9 3 Spare parts hydraulics FriwaMaxi without circulation 6406662 with circulation 6406663 24 10 Technical data 25 10 1 Pressure drop characteristic curves FriwaMidi 26 10 2...

Page 3: ...ions of the corresponding manufacturer Item Item number Controller FC3 8 Pump primary Circulation Heat exchanger FriwaMidi 6405640 Grundfos UPM2 25 75 Optional Grundfos UPM2 15 75 CIL2 40 plates 6405641 Grundfos UPM2 25 75 Grundfos UPM2 15 75 CIL2 Item Item number Controller FC3 8 Pump primary Circulation Heat exchanger FriwaMaxi 6406662 Grundfos UPML 25 105 Optional Grundfos UPM2 15 75 CIL2 60 pl...

Page 4: ...e sensors on the heating flow Temperature sensor on the domestic hot water outlet Flow meter on the domestic hot water outlet Fill and drain valve for draining the heat exchanger Vent plug for venting the heat exchanger 1 3 Designated use The domestic hot water module must only be used in heating installations between the buffer tank and the domestic hot water circuit Due to its design the station...

Page 5: ...levant local and national regulations accident prevention regulations of the professional association instructions and safety instructions of this manual WARNING Danger of scalding due to hot water Undesirable circulation of water in the primary circuit can cause the exit of water of up to 90 C at the withdrawal point External pumps must not be installed between the domestic hot water module and t...

Page 6: ...ve to avoid that EPDM gets in contact with substances containing mineral oils Use a lubricant based on silicone or polyalkylene and free of mineral oils such as Unisilikon L250L and Syntheso Glep 1 of the Klüber company or a silicone spray NOTICE Malfunction The domestic hot water module must be integrated in the potential equalisation of the electric installation This can be guaranteed by establi...

Page 7: ...k valve B Primary pump C Non return valve with drain valve D Circulation pump E Piston valve with drain valve F Piston valve with drain valve G Piston valve with drain valve and temperature sensor H Fill and drain valve and temperature sensor I Flow meter FlowSonic J Plate heat exchanger K Circulation line L Vent valve primary circuit M Temperature sensor and pressure relief valve 10 bars suitable...

Page 8: ...an the installation WARNING Danger of scalding due to hot water Undesirable circulation of water in the primary circuit can cause the exit of water of up to 90 C at the withdrawal point External pumps must not be installed between the domestic hot water module and the buffer tank The domestic hot water module must not be connected to a distribution manifold Mounting example FriwaMidi with optional...

Page 9: ...5 C 0 8 litre 50 C 1 0 litre 55 C 1 4 litres 70 C 45 C 0 7 litre 50 C 0 8 litre 55 C 0 9 litre 80 C 45 C 0 5 litre 50 C 0 6 litre 55 C 0 7 litre Calculation example for the dimensioning of the buffer tank Temperature buffer tank 60 C Maximum withdrawal quantity needed 20 l min Domestic hot water temperature set at the controller 45 C How large must the tank be to allow for a continuous withdrawal ...

Page 10: ...riod of time Temperature dependent operation In this operating mode the circulation only starts if the adjustable minimum temperature on the circulation temperature sensor is not reached during the chosen period of operation The circulation stops after the required temperature has been reached or after the end of the chosen period of time The operating modes can be combined with one another as wis...

Page 11: ...the station does not replace the safety groups of the potable water connection as per DIN 1988 The pressure relief valve only protects the module from over pressures in case of servicing NOTICE Damage to property If there are water supplies that may cause pressure surges for example flush valves washing machines or dishwashers connected to the same mains as the domestic hot water module we recomme...

Page 12: ...of the installation 1 Determine the mounting location of the domestic hot water module near the buffer tank The pipes in the heating circuit must not exceed a length of 4 m for DN 32 2 You can use a drilling template in order to facilitate the installation You will find the drilling template on the station 3 Copy the measures for the mounting holes to the wall 4 Drill the holes and insert adequate...

Page 13: ...t water circulation return connection 1 ext thread flat sealing 3 Secondary side cold water inlet connection FriwaMidi 1 ext thread flat sealing connection FriwaMaxi 1 ext thread flat sealing 4 Secondary side hot water outlet connection FriwaMidi 1 ext thread flat sealing connection FriwaMaxi 1 ext thread flat sealing 5 Primary side flow from the buffer tank connection FriwaMidi 1 ext thread conne...

Page 14: ... with a check valve in order to avoid unwanted gravity circulation For venting and flushing the installation the check valves must be open Turn the ball valves therefore into the position 45 The check valve is not operating During operation all the ball valves must be completely open position 0 Position 0 Position 45 Position 90 Check valve is operating flow only in flow direction Check valve is n...

Page 15: ...0 2 Fill the storage tank using the already existing fill valves until an operating pressure of about 1 5 bars is reached Use appropriate water according to VDI 2035 ÖNorm H5195 1 3 Manipulate the vent valve L cautiously to let the air escape 5 Close the vent valve L 6 Check the operating pressure of the storage tank after venting and increase the pressure if necessary 7 Open the ball valves A and...

Page 16: ...V 50 Hz using the premounted connection cable 2 Start the pump H1 in the main menu of the controller in the manual mode PWM signal 100 see controller instructions page 19 3 Let the pump run for several minutes to vent the domestic hot water module 4 If the air noises do not stop carefully manipulate the vent valve L while the pump is still running and let the air escape 5 If the air noises have st...

Page 17: ...er run for about 2 minutes to deaerate the secondary circuit Close all withdrawal points in the secondary circuit afterwards 9 Make sure that the domestic hot water module is correctly integrated into the potential equalisation of the installation 10 Set the desired domestic hot water temperature at the controller see page 24 11 The FriwaMidi FriwaMaxi is now ready for operation ...

Page 18: ...he domestic hot water temperature the withdrawal flow rate and the temperature of the buffer tank and show their impact on the heat transfer capacity of the Friwa Example 1 Domestic hot water temperature at the withdrawal point 45 C Temperature in the buffer tank 60 C FriwaMidi maximum withdrawal flow rate 50 l min transfer capacity 121 kW FriwaMaxi maximum withdrawal flow rate 77 l min transfer c...

Page 19: ... the controller 60 C Temperature in the buffer tank 70 C FriwaMidi maximum withdrawal flow rate 53 l min transfer capacity 129 kW FriwaMaxi maximum withdrawal flow rate 82 l min transfer capacity 200 kW Example 2 Domestic hot water temperature at the controller 60 C Maximum tap volume rate 60 l min FriwaMidi temperature in the buffer tank 75 C transfer capacity 155 kW FriwaMaxi temperature in the ...

Page 20: ...ondary side The possible withdrawal flow rate l min at the tap depends on the domestic hot water temperature set at the controller and on the temperature available in the buffer tank The recommended maximum domestic hot water flow rate through the domestic hot water module FriwaMidi is 65 l min The flow rate of the FriwaMaxi is 88 l min The following table illustrates the correlation between the s...

Page 21: ...W 60 C 37 l min 58 l min 53 l min 82 l min 129 kW 200 kW 80 C 45 C 65 l min 88 l min 158 kW 214 kW 50 C 65 l min 88 l min 74 l min 100 l min 181 kW 244 kW 55 C 57 l min 87 l min 72 l min 111 l min 176 kW 272 kW 60 C 49 l min 75 l min 69 l min 107 l min 169 kW 262 kW at a cold water temperature of 10 C reheating not considered Maximum flow rate 65 l min with a pressure loss of the FriwaMidi of 1000...

Page 22: ...Complaints and requests orders of spare parts will only be processed with information on the serial number The serial number is placed in the lower right corner of the support sheet of the station 9 1 Spare parts control and insulation FriwaMidi 6405640 6405641 and FriwaMaxi 6406662 6406663 ...

Page 23: ...9 Spare parts specialist 2016 07 99640x6xx mub de V08 23 9 2 Spare parts hydraulics FriwaMidi without circulation 6405640 with circulation 6405641 only included in the scope of delivery of 6405641 ...

Page 24: ...9 Spare parts specialist 24 99640x6xx mub de V08 2016 07 9 3 Spare parts hydraulics FriwaMaxi without circulation 6406662 with circulation 6406663 only included in the scope of delivery of 6406663 ...

Page 25: ...sible pressure primary 3 bars secondary 10 bars Operating temperature 2 95 C Equipment Check valve 2 x 200 mm wc 2 x 400 mm wc Primary pump High efficiency pump with PWM control 3 70 W High efficiency pump with PWM control 6 140 W Secondary pump optional High efficiency pump with PWM control 5 63 W optional High efficiency pump with PWM control 5 63 W Heat exchanger 40 plates 60 plates Flow rate s...

Page 26: ...a 26 99640x6xx mub de V08 2016 07 10 1 Pressure drop characteristic curves FriwaMidi Pressure m wc Pressure kPa Flow rate m h 10 2 Pressure drop characteristic curves FriwaMaxi Pressure m wc Pressure kPa Flow rate m h ...

Page 27: ...her additionally installed components Circulation set Return distribution set Others Have both circuits been correctly flushed and vented no air noises in the pump Vented Are all the shut off valves open in the cold water line Open Is there a pressure of at least 1 5 bars on the primary side Checked Is there a pressure of at least 2 5 bars on the secondary side Checked Is there an error message on...

Page 28: ...PAW GmbH Co KG Böcklerstraße 11 D 31789 Hameln Germany www paw eu Phone 49 0 5151 9856 0 Fax 49 0 5151 9856 98 99640x6xx mub de V08 2016 07 ...

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