Cooling Mode; Hot Gas Bypass Mode - Fluke 7341 User Manual

7341
Users Guide
To change to manual reset mode press "UP" and then "SET".
Cto=rst

Cooling Mode

The cooling mode determines whether refrigeration is in Auto mode, On, or Off.
Normally the cooling mode is set to Auto mode. In the Auto mode, the refrigeration is
'On' below approximately 60°C. Note: If the fluid is cooling from above 60°C, the
refrigeration turns on at approximately 59°C. If the fluid is heating from below 60°C, the
refrigeration shuts off at 60°C. If the set point is more than 5°C higher than the current
bath temperature, the refrigeration will automatically shut off until needed to maintain the
temperature selected. There may be times when Auto mode is undesirable. In that case,
the refrigeration may be set to On or Off. When the refrigeration is set to On or Off, the
refrigeration is on or off for all temperatures.
The refrigeration may be damaged or the lifetime shortened if
used above 60°C for more than one hour.
The parameter is indicated by,
CooL=rst
Press "SET" to access the parameter setting.
Auto
To change to On or Off mode, press "DOWN" until the desired mode appears and then
press "SET".
On
OFF
Individual steps may be skipped by pressing "EXIT"

Hot Gas Bypass Mode

The hot gas bypass (HGb) system is a method of reducing cooling or refrigeration
capacity. It is normally used above approximately 0°C. Reducing cooling capacity helps
improve temperature stability in the bath and reduces energy consumption. The HGb
system is normally in the automatic mode which switches on (reducing capacity) when at
set-points above 0°C. When the bath is scanning to lower temperatures (greater than 2°C
below the starting temperature) the HGb turns off for full cooling capacity for all
temperatures below the maximum refrigeration limit even above 0°C.
There are three HGb modes; Auto, On, or Off. Normally HGb mode is set to Auto mode.
If for some reason the automatic mode is undesirable, the HGb mode can be set to always
On or Off.
The parameter is indicated by,
Hgb
Press "SET" to access the parameter setting.
Auto
To change to On or Off mode, press "DOWN" until the desired mode appears and then
press "SET".
9-14
Cutout set for manual reset
CAUTION
Cooling mode parameter
Cooling mode set for automatic
Cooling mode set to on
Cooling mode set to off
HGb mode parameter
HGb mode set for automatic