Honeywell NA 228 S-B Product specification sheet

225

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

Product specification sheet

Automatic refilling unit

for compressor level control

NA 228 S-B

Application

The NA 228 S-B automatic refilling unit with DVGW-tested back-

flow 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

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.

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

vom Kaltwassernetz

230V ~

50/60 Hz

220V~50Hz

UW

Z 52

1996

SPX

0

5

10

15

bar

16

4

2

8

6

bar

0

GRÄSSLIN

h

Nachfüllautomat Typ: NA 228

TÜV / DVGW

30 Watt

226

Braukmann Water Control

.

Honeywell AG

Subject to change 03/99

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

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

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

NETZ

EIN/AUS

00 00 000 0

16

0

5

10

15

bar

Fremdanschluß

- potentialfrei -

zur Heizungsanlage

B

H

T

Automatic Refilling unit NA 228-SB