Grant Instruments RC - Manual (Page 7)

Recirculating Chiller
Part No 09931/Issue 8 Page 7 August 2001
2.3 Siting the chiller
Lift the chiller by the four bottom corners. Take care when lifting as the chillers weigh between 42
and 90 kg when empty.
For the most efficient operation, position the chiller so that the air flow through and around it is
not restricted. There should be at least 100mm clearance on all sides. Lock the wheels to ensure
that the chiller stays in place.
If the RC is to be stored below a bench, make sure that the hosing and power cable are long
enough to allow it to be removed.
Do not move the chiller while it is operating.
2.4 Filling the reservoir
Liquid specification.
+10°C to +60°C water (tap or distilled)
-10°C to +30°C 60% water, 40% inhibited ethylene glycol.
WARNING - inhibited ethylene glycol is TOXIC : Follow the manufacturer's instructions. For safe
disposal consult your local Environmental Health Office.
Check that all hose connections are liquid tight.
Set the water/glycol switch to water/glycol. Remove the filler cap and fill the reservoir. Allow the
liquid level to fall, refill until the liquid level remains constant. For RC3000G remove the cap from
the overflow tap. Open the tap and position a container under the tap. Fill the reservoir until liquid
flows from the overflow. Close the tap and proceed as: RC350G, RC400G and RC1400G. If the
system is circulating through an open tank, refit the filler cap and fill the open tank. Plug in and
switch the power on. A buzzer will sound and the general alarm will light. This indicates that
there is no flow. Press the flow fail override switch for about 5 seconds and release. The buzzer
and general alarm light will switch off and the pump will run. To stop the chiller cooling or heating
during filling switch off the cooler (RC350G, RC400G, RC1400G only) and set the temperature
equal to the actual temperature. Refer to section 3.2 for temperature setting.
In a closed loop system, to prevent excessive pressures occurring when the liquid circulates
system, allowances for the expansion of the liquid with temperature must be made. Therefore
the system should not be filled to more than 95% of its total volume, thus leaving 5% for
expansion at the top of the system. DO NOT OVERFILL THE SYSTEM.
For open loop circulation top up the tank.
With the PRES Reservoir on a closed loop system filling is done by the reservoir. First remove
the cap from the main reservoir on top panel of the unit. Pour water in until it covers the cooling
coil and just starts to come up the side of the filler tube (this will allow for expansion). Then
replace the cap. Filling can then be done through the PRES Reservoir on the rear panel by
removing the top cap and pouring in water whilst switching on the pump. Any air in the system
should be flushed through and should appear bubbling up at the bottom. Once it stops bubbling,
fill the reservoir until 1/3 full and replace the cap. it’s important that you replace the cap to
prevent any syphoning from occuring once the unit is switched off.
2.5 By-pass
Systems where there is low flow due to restrictions in the external system (below 2 litres per
minute) it is recommended to fit a by-pass (RC-BYP).
To operate with the RC-BYP, fill the system as much as possible and, with the by-pass valve fully
open (clockwise), start the circulator. Continue to top up the reservoir until the level remains
stable. Replace the filler cap securely and proceed to close the by-pass valve (anticlockwise)
until it is fully closed or the circulator cuts out. If the circulator cuts out, open the by-pass valve
1/2 a turn and press the flow fail reset. The circulator should start and continue to pump, if not
continue to open the by-pass valve in 1/2 turn stages. Once the unit is pumping, open the filler
cap, top up the reservoir, then replace and securely refit the filler cap.