Indoor unit
CYLINDER
- Safety fitting
The indoor unit shall be equipped with the following protective fittings:
• Safety valve for central heating 3 bar (0.3MPa).
• Safety valve for the circuit of the expansion vessel 5 bar (0.5MPa).
• Safety valve for DHW tank 10 bar (1MPa).
• Vent valve
• NExpansion vessel 12l.
• Pressure gauge - 3-way valve
The valve is installed to close the flow through the central heating system and to redirect it to the hot water supply system. A 2-point (SPST) cylinder is used to control the valve.
- Domestic hot water tank
The DHW tank is made of stainless steel. The inlet pipe that the water flows through from the plate heat exchanger is L-shaped, so the stratification(stratification) of the hot water in the cylinder is maintained when the cylinder is reheated. You don't have to worry about running out of hot water as you would with a conventional coil in the tank. The feed water temperature can be maintained at a high level until all the hot water in the tank has been consumed. Thanks to the use of two temperature sensors, the amount of hot water available can be flexibly adjusted to current needs.
Location of temperature sensors
- Electrical heater
The Ecodan indoor units are equipped with integrated, sequential switching, electrical heaters. They act as peak/emergency source in heat pump-based systems. Depending on the demand, the following are activated in sequence:.
• First stage of the heater
• Second stage of the heater
• Both stages at the same time
Single phase heater
Three-phase heater
- Flowmeter
The flowmeter in the heat pump has three main roles:
• tActs as a protection against lack of flow through the heat pump's internal module
• tMonitors the current flow rate (reading available from the main heat pump controller)
• tCurrent readings are collected and used to monitor energy produced
- Lime trap
Mitsubishi Electric has developed a system unique to the market to protect the plate heat exchanger and guarantee a long service life for the system. When tap water is heated to a set temperature, it is natural for deposits to precipitate and build up. These deposits can reduce the heat exchange efficiency of the exchanger. Ecodan heat pump cylinders are equipped with a lime trap (filled with steel wool) to capture precipitated particles. This is located behind the plate heat exchanger due to the higher temperatures prevailing there. - Plate heat exchanger
The Ecodan heat pumps use brazed plate heat exchangers from Alfa Laval. These provide an efficient heat exchange between the refrigerant and water/glycol on the secondary side. Depending on the capacity of the outdoor unit and the refrigerant, an appropriately sized exchanger is dedicated to the unit. - Circulation pump
Grundfos circulation pumps are responsible for the water flow through the indoor units. In the technical documentation for the indoor unit, you can find diagrams for the circulation pumps installed in them.
- Plate exchanger - DHW
In units with a built-in DHW tank, water is prepared on an ongoing basis in a flow-through manner. The water is heated by a separate built-in plate heat exchanger. Cold water is pumped by a small circulating pump from the lower part of the tank and, after heating, is fed into the upper part. Then hot water is drawn from the upper part. By using such a heating technique, it was possible to reduce the cubic volume of the unit, which is impossible if the unit had to be equipped with a coil.
- Circulation pump A562
Grundfos circulation pumps are responsible for the water flow through the indoor units. In the technical documentation for the indoor unit, you can find diagrams for the circulation pumps installed in them. A566:A573
Water circuit diagrams