Mitsubishi Electric EHGT17D-YM9ED Service Manual page 96

Annual Maintenance Log Book
Contractor name
Site name
Cylinder unit maintenance record sheet
Warranty number
No. Mechanical
Turn OFF water supply, drain DHW tank, remove mesh from strainer
1
clean and replace in strainer. *1
Keep water supply OFF, open hot water taps and check the primary-side
2
expansion vessel charge pressure. Top up if necessary (1 bar).
Keep water supply OFF and check the potable vessel charge pressure.
3
Top up if necessary (3.5 bar).
Keep water supply OFF. In hard water areas de-scaling of the immersion
4
heaters may be required.
Drop the primary/heating system pressure to zero check and if neces-
5 sary top up the expansion vessel (1 bar). Air valve of expansion vessel is
TR-412.
Turn water supply ON, open the pressure relief valve and then the expan-
sion relief valve in turn. Check for unrestricted discharge to the tundish
6
and that the valves reseat correctly. Check there are no blockages in the
tundish and associated pipework.
Check and if necessary top up the concentration of anti-freeze/inhibitor (if
7
used in the system).
Top up the primary/heating system using a temporary backflow preven-
8
tion filling loop and re-pressurise to 1 bar.
Heat system and check pressure does not rise above 3 bar and no water
9
is released from the safety valves.
10 Release any air from the system.
To check the 3-way valve for inside leaks, confirm that the temperature of
11
the heat emitter does not rise when running the DHW mode.
Electrical
1 Check condition of cables.
2 Check rating and fuse fitted on the electricity supply.
Controller
1 Check field settings against factory recommendations.
2 Check operation of motorized valves ensure they reseat correctly.
3 Check battery power of wireless thermostat and replace if necessary.
Heat pump unit maintenance record sheet
Model number
Mechanical
1 Inspect grill and air inlet for trapped debris/damage.
2 Check condensate drain provision.
3 Check integrity of water pipework and insulation.
4 Check all electrical connections.
5 Check and record the operation voltage.
* Checks should be carried out once a year.
*1 Be sure to reattach the mesh after washing.
Note: Within the first couple of months of installation, remove and clean the cylinder unit's strainer mesh plus any that are fitted external to the cylinder
unit. This is especially important when installing on an existing system.
In addition to annual servicing, it is necessary to replace or inspect some parts after a certain period of system operation. Please see tables below for detailed instruc-
tions. Replacement and inspection of parts should always be done by a competent person with relevant training and qualifications.
Parts which require regular replacement
Parts
Pressure relief valve (PRV)
Manometer
OCH722A
Replace every Possible failures
6 years Water leakage
Engineer name
Site number
Model number
Serial number
Frequency Notes
Frequency Notes
Frequency Notes
Serial number
Frequency Notes
Parts which require regular inspection
Parts Check every
Pressure relief valve 1 year
(3 bar) (turning the knob manually)
Immersion heater
2 years
(Optional part)
Water circulation pump
20,000 hrs (3 years)
(Primary circuit)
Brine circulation pump 30,000 hrs (4.5 years)
Parts which must NOT be reused when servicing
* O-ring
* Gasket
Note:
• Always replace the gasket for pump with a new one at each regular main-
tenance (every 20,000 hours of use or every 3 years).
96
Possible failures
PRV would be fixed and ex-
pansion vessel would burst
Earth leakage causing
circuit breaker to activate
(Heater is always OFF)
Water circulation pump
failure
Brine circulation pump failure