Honeywell NA 228 S-B Product specification sheet
vom Kaltwassernetz
NA 228 S-B
Automatic refilling unit
for compressor level control
Product specification sheet
Application
The NA 228 S-B automatic refilling unit with DVGW-tested backflow preventer permits the fixed connection of closed heating or
cooling systems to the drinking water supply network.
It integrates a backflow preventer, a check valve and a water
meter in one single unit. The automatic refilling unit maintains
pressure between prescribed upper and lower limits in closed
4
6
GRÄSSLIN
2
bar
8
0
h
220V~50Hz
Z 52
UW
10
5
SPX
1996
15
bar
16
0
heating and cooling systems. It prevents back flow, back
syphonage or back pressure of the heating or cooling water
into the potable water network. Limitation of the refilling time is
provided as well as the facility for fast and automatic refilling of
the system. In addition, build up of steam in the system caused
by pressure loss is prevented.
50/60 Hz
30 Watt
Nachfüllautomat Typ: NA 228
TÜV / DVGW
230V ~
Construction
The automatic refilling unit comprises:
● Powder coated pressed steel housing
● Drinking water and system connection with shutoff
ball valve
● Electronic time relay
● Fault indicator lamp and cut-out button
● Pressure gauges for inlet and system pressure
● Discharge tundish
● Electrical plug for compressor side connection
● ON/OFF switch
● 1 metre connection cable without plug
● Water meter
● Bush for cable connection to a building management
system
● Operating-time meter
* For temperatures above 100 ºC, the pressure at the highest point in the cold system
must be at least 1.0 bar above the operating pressure (static height plus 1.0 bar).
**A pressure reducing valve must be fitted before the refilling unit for pr essur es
above 6.0 bar
Subject to change 03/99
Special Features
● Components DVGW-approved
● Electrical changeover valve for control of the backflow
preventer
● Supplementary hot-water-resistant check valve for
increased protection of the drinking water network
● Setting facility for fast filling or refilling of the system
● Time relay, for limitation of the refilling period
● Standardised discharge connection
● Remote volt-free connection
● Bush for cable connection to a building management system
● Circuit protection for volt-free connection
● Operating-time meter, measures the refilling time
● Water meter, measures the refills
Range of Application
The following operating data applies for the downstream system:
System pressure: Maximum 6.0 bar
Temperature: Maximum 120 ºC
Technical Data
Refilling Flow rate 110 litres/h at ∆p = 2.0 bar
Fast filling Flow rate finely adjustable
between 110 litres/h and
1100 litres/h at ∆p = 2.0 bar
Filling duration Adjustable between 5 and 100 minutes
Water inlet pressure Minimum 3.0 bar, maximum 6.0 bar**
Remote connection 220 V, 50/60 Hz to activate compressor
level indicator switch „lack of water“
Volt-free contact
Supply voltage 230V, 50/60 Hz
Power consumption 30W
Connection size: R
1
/2" and Ø15
225
Automatic Refilling unit NA 228-SB
T
NETZ
EIN/AUS
zur Heizungsanlage
Fremdanschluß
- potentialfrei -
B
00 00 000 0
5
0
Method of Operation
If the system pressure falls below the lower set value, for
example through leakage losses, then the changeover valve is
opened by the compressor level control „lack of water“ and
thereby permits water 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 compressor level control „vessel
H
10
bar
15
16
filled“ closes the changeover valve and the backflow preventer
goes to the shutoff position. The time relay then returns to the
initial position.
If the inlet pressure falls to the set pressure of the backflow
preventer during the automatic refilling operation, then the
backflow preventer (2 bar) automatically goes to the shutoff
position. The shutoff position of the backflow preventer is
indicated in the viewing window (green visible = shutoff
position)
Option
NA 228 S-B
Connection size R
1
/2"
Soldered connection size (mm) Ø15
Weight (approx. kg) 16
Dimensions (mm)
H 380
B 370
T 160
Test Certificate Number 101/87/147
226
Braukmann Water Control . Honeywell AG
Subject to change 03/99
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