User manual HONEYWELL NA 228 S-A

[. . . ] NA 228 S-A Automatic Refilling Unit for closed heating or cooling systems Product specification sheet Application The NA 228 S-A automatic refilling unit with DVGW-tested backflow preventer permits the fixed connection of closed heating or cooling systems to the drinking water supply network. [. . . ] **A pressure reducing valve must be fitted before the refilling unit for pressures above 6. 0 bar Subject to change 03/99 Automatic Refilling unit NA 228-SA Method of Operation If the system pressure falls to below the lower set value, for example through leakage losses, then the changeover valve is opened by electrical impulse via the pressure switch and thereby permits supply to the backflow preventer. The inlet pressure moves the backflow preventer to the flow position and the system is refilled until the pressure rises to the upper set limit. The time period of the refill is monitored by the time relay and the operating time counter. Once the upper limit value has been reached, the pressure switch closes the changeover valve and the backflow preventer goes to the shutoff position (open to atmosphere). The time relay then returns to the initial position. If the inlet pressure falls to the operating pressure of the backflow preventer (2 bar) during the automatic refilling operation, then the backflow preventer automatically goes to the shutoff position (open to atmosphere). The shutoff position of the backflow preventer is indicated in the viewing window (green visible = shutoff position) Option NA 228 S-A T NETZ EIN/AUS B Fremdanschluß - potentialfrei - zur Heizungsanlage 00000000 5 0 bar 10 16 15 Connection size R Soldered connection size (mm) Weight (approx. kg) Dimensions (mm) H B T Test Certificate Number /2" Ø15 16 380 370 160 101/87/147 1 222 Braukmann Water Control . [. . . ] Box 1347 D - 74819 Mosbach-Germany Phone: (49) 62 61/ 0 62 61/8 10 · Fax: 0 62 61/8 13 09 224 http://europe. hbc. honeywell. com [. . . ]