Installing The Boiler; Expansion Vessel - DeDietrich MS 24 MI FF Operating And Installation Instructions

After deciding the exact location of the boiler, make sure there is sufficient room to perform maintenance operations (at
least 450 mm of headroom is required in order to replace the expansion vessel).
Connect the system to the gas and water inlets present on the lower bar of the template. Fit two G3/4 taps (flow and
return) on the central heating circuit; these taps make it possible to carry out important operations on the system without
draining it completely. If you are either installing the boiler on an existing system or replacing one, as well as the above,
fit a settling tank under the boiler on the system return line in order to collect any deposits and scale circulating in the
system after flushing. After fixing the boiler to the template, connect the flue and air ducts, supplied as accessories, as
described in the following sections.
If the model 24 MI - 24 natural draught boiler is installed, connected it to the flue with a metal pipe resistant to normal
mechanical stress, heat, products of combustion and relative condensate.
IMPORTANT
After filling the boiler, vent the entire internal circuit and the system as follows:
• close the gas on-off valve;
• power the boiler.
• open the vent valve on the pump body;
• press ( ) to set the boiler in the "WINTER" operating mode;
• send a heat demand from the room thermostat;
• open a hot water tap to alternate CH demand with DHW demand;
• after a few ignition attempts the boiler will shut down (error E01 appears on the display);
• to rest, press and hold down "R" for at least 2 seconds;
• repeat the procedure at least another two times;
• close the vent valve.
After venting the boiler circuit, proceed with initial lighting.

EXPANSION VESSEL

The boiler features a standard 6-litre expansion vessel with a pre-charge pressure of 1 bar. The maximum volume of water in
the system is calculated according to hydrostatic pressure at an average water temperature of 80°C (flow: 95°C return: 75°C).
Hydrostatic pressure (m)
Maximum system volume (l)
INSTALLATION INSTRUCTIONS
13. INSTALLAZIONE DELLA CALDAIA

14. INSTALLING THE BOILER

5 6
110 105
7 8 9
95 85 77
75
10
70
71.03982.03 - EN