Carrier AQUASNAP 30RB060-390 Spécifications télécharger pdf (Page 43)

SYSTEM PRESSURIZATION — A proper initial cold fill

pressure must be established before filling of the unit. The

initial cold fill pressure is the pressure applied at the filling

point to fill a system to its highest point, plus a minimum

pressure at the top of the system (4 psig minimum [27.6 kPa])

to operate air vents and positively pressurize the system. The

expansion tank is very important to system pressurization. The

expansion tank serves several purposes:

1. Provide NPSH (net positive suction head) required for the

pump to operate satisfactorily.

2. Set system pressure.

3. Accommodate expansion or contraction of water due to

temperature changes.

4. Act as a pressure reference for the pump.

The expansion tank pressure must be set BEFORE the

system is filled. Follow the manufacturer’s recommendation

for instructions on setting the pressure in the expansion tank.

The net positive suction head pressure required information is

provided on the pump curves in Fig. 39-46 for units with facto-

ry-installed hydronic kits. See Table 6 for pump impeller sizes.

Once the system is pressurized, the pressure at the connec-

tion point of the expansion tank to water piping will not change

unless the water loop volume changes (either due to addition/

subtraction of water or temperature expansion/contraction).

The pressure at this point remains the same regardless of

whether or not the pump is running.

Since the expansion tank acts as a reference point for the

pump, there cannot be two reference points (two expansion

tanks) in a system, unless manifolded together. Where two or

more 30RB chillers with the hydronic option are installed in

parallel, there should not be more than one expansion tank in

the system, unless manifolded together as seen in Fig. 36. It is

permissible to install the expansion tank(s) in a portion of the

return water line that is common to all pumps, providing that

the tank is properly sized for combined system volume.

If the application involves two or more chillers in a primary

secondary system, a common place for mounting the expan-

sion tank is in the chilled water return line, just before the

decoupler. See Fig. 36 for placement of expansion tank in

primary-secondary systems.

If a diaphragm expansion tank is utilized (a flexible

diaphragm physically separates the water/air interface) it is not

recommended to have any air in the water loop. See the section

on air separation on page 40 for instructions on providing air

separation equipment.

FILLING THE SYSTEM(S) — The initial fill of the chilled

water or heat reclaim system must accomplish three goals:

1. The entire piping system must be filled with water.

2. The pressure at the top of the system must be high enough

to vent air from the system (usually 4 psig [27.6 kPa] is

adequate for most vents).

3. The pressure at all points in the system must be high

enough to prevent flashing in the piping or cavitation in

the pump.

The pressure created by an operating pump affects system

pressure at all points except one — the connection of the

expansion tank to the system. This is the only location in the

system where pump operation will not give erroneous pressure

indications during the fill. Therefore, the best location to install

the fill connection is close to the expansion tank. An air vent

should be installed close by to help eliminate air that enters

during the fill procedure.

When filling the system, ensure the following:

1. Remove temporary bypass piping and cleaning/flushing

equipment.

2. Check to make sure all drain plugs are installed.

DILUTED

CLEANING

AGENT

SYSTEM

POT FEEDER AND

TRANSFER PUMP

30RB UNIT

TO DRAIN

TEMPORARY

PUMP

TEMPORARY

BYPASS

Fig. 37 — Typical Set Up for Cleaning Process

DILUTED

CLEANING

AGENT

SYSTEM

SIDE

STREAM

FILTER

POT FEEDER AND

TRANSFER PUMP

30RB UNIT

TO DRAIN

TEMPORARY

PUMP

TEMPORARY

BYPASS

Fig. 38 — Cleaning Using a Side Stream Filter

1 2 ... 38 39 40 41 42 43 44 45 46 47 48 ... 71 72

Commentaires sur ces manuels

Pas de commentaire

Carrier AQUASNAP 30RB060-390 Spécifications Page 43

Commentaires sur ces manuels

Produits connexes et manuels pour Pompes à chaleur Carrier AQUASNAP 30RB060-390