Annual Maintenance - Mitsubishi Electric EHPT Serie Manual De Instalación

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Service and Maintenance

Annual Maintenance

It is essential that the cylinder unit is serviced at least once a year by a qualified individual. Any required parts should be purchased from Mitsubishi Electric. NEVER bypass
safety devices or operate the unit without them being fully operational. For more details, refer to service handbook.
Notes
▪ W ithin the first couple of months of installation, remove and clean the cylinder unit's strainer plus any additional filter items that are fitted external to the
cylinder unit. This is especially important when installing on an old/existing pipe work system.
▪ The PRV valve and T&P valve (No. 8, 20 and 21 on Figure 3.1) should be checked annually by turning the knob manually so that the medium is discharged,
thus cleaning the seal seat.
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 instructions.
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
Inlet control group (ICG)*
*
OPTIONAL PARTS for UK
<Draining the cylinder unit and its sanitary heating circuit (local)>
WARNING: DRAINED WATER MAY BE VERY HOT
1. Before attempting to drain the cylinder unit isolate from the electrical supply to prevent the immersion and booster heaters burning out.
2. Isolate cold water feed to DHW tank.
3. Open a hot water tap to allow draining without creating a vacuum.
4. Attach a hose to the DHW tank drain cocks (No. 22 and 23 on Figure 7.1). The hose should be able to withstand heat as the draining water could be very hot. The hose
should drain to a place lower than the DHW tank bottom to encourage siphoning. Begin draining by opening drain cock.
5. When the DHW tank is drained close drain cock and hot tap.
6. For primary circuit, attach hose to water circuit drain cocks (No. 6 on Figure 3.1). The hose should be able to withstand heat as the draining water could be very hot. The
hose should drain to a place lower than the drain cock to encourage siphoning. Open the pump valves and the strainer valves.
7. Water remains in the strainer still after the cylinder unit was drained.
Drain the strainer by removing the strainer cover.
Replace every Possible failures
6 years Water leakage
Parts which require regular inspection
Parts
Pressure relief valve (3bar)
Temperature and pressure
relief valve
Immersion heater
Water circulation pump
(Primary circuit)
Parts which must NOT be re-used 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).
23
22
<Figure 7.1>
Check every Possible failures
1 year PRV would be fixed and
( t u r n i n g t h e k n o b expansion vessel would
manually) burst
Earth leakage causing
2 years circuit breaker to activate
(Heater is always OFF)
Water circulation pump
20,000 hrs (3 years)
failure
en
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