Thermistor Installation - Hitachi DXF-2.0A1 Operation Installation Maintenance Manual

3.5 Thermistor Installation
♦ Liquid and gas pipes thermistors
2 types of thermistors are supplied with the control
box. See below for the purpose and identification.
PCB Socket /
Thermistor
Item
Connector
Color
Liquid Pipe
Black
Thermistor
Gas Pipe
Yellow
Thermistor
Location of Liquid Pipe Thermistor:
Install the thermistor on the coldest point of liquid
line before the distributor.
Heat
Heat
Exchanger
exchanger
Distributor
Distributor
CORRECT
Location of Gas Pipe Thermistor:
Install the thermistor on the outlet of the heat
exchanger as close as possible to the heat
exchanger.
Heat
Heat
Exchanger
exchanger
CORRECT
NOTES:
1. Put the thermistor cable slightly down to avoid
water accumulation on top of the thermistor and
add a pull-relief to the thermistor cable to avoid
strain on the thermistor cable.
2. In case that the thermistors supplied with DX-Kit
are not long enough, please make sure that the
length extension is properly done avoiding the
sensing distortion and that the joint is properly
insulated and waterproofed to avoid any
electrical failure.
Fixing the thermistor:
1 Fix the thermistor with insulating aluminum tape
(field-supplied) to make sure the heat transfers.
Make sure there is a good contact between the
thermistor and pipe.
Maximize the
Maximize the contact
contact
Most sensitive
Most sensitive point of the thermistor
point of the thermistor
18
PCB
Thermistor
Socket
Length (m)
Number
THM3 10
THM5 10
INCORRECT
INCORRECT
2 Put the insulating tape (field-supplied) around
the thermistor in order to avoid loosening of the
thermistor after some years.
3 Fasten the thermistor with 2 plastic bands (field-
supplied).
4 Insulate the thermistor with the insulation sheet
(field-supplied).
♦ Air Thermistor
2 air thermistors are supplied with the control box.
The purpose and identification of each one is as
follow:
PCB Socket /
Thermistor
Item
Connector
Color
Inlet Air
Blue
Thermistor
Outlet Air
Red
Thermistor
Install the thermistors as far as possible from where
the effects of heat sources such as heat exchangers
and heaters, etc. are minimized Inlet/Outlet air
temperature can be measurable as shown in System
Overview on page 5 and 6.
NOTES:
1. In case that the thermistors supplied with DX-Kit
are not long enough, please make sure that the
length extension is properly done avoiding the
sensing distortion and that the joint is properly
insulated and waterproofed to avoid any
electrical failure.
2. Fix the thermistors securely with plastic band in
proper place.
PCB
Thermistor
Socket
Length (m)
Number
THM1 10
THM2 10
P5417151-rev.1