Mitsubishi Electric ecodan EHPT20X-MEHEW Installation Manual page 13

Cylinder unit

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Service manual (108 pages)

Table Of Contents

Table of Contents

Installation

Sizing Expansion Vessels

Expansion vessel volume must fit the local system water volume.

To size an expansion vessel for the heating circuit, the following formula and

graph can be used.

When the necessary expansion vessel volume exceeds the volume of an built-in

expansion vessel, install an additional expansion vessel so that the sum of the

volumes of the expansion vessels exceeds the necessary expansion vessel

volume.

* For installation of an E**T***-*M*EE* model, it is essential to appropriately

provide and install a suitable primary-side expansion vessel in the field as the

model DOES NOT come fitted with a primary-side expansion vessel.

ε × G

Where;

V =

P ¹ + 0.098

V : Necessary expansion vessel volume [L]

1 −

P ² + 0.098

G : Total volume of water in the system [L]

P ¹ : Expansion vessel setting pressure [MPa]

P ² : Max. pressure during operation [MPa]

Graph to the right is for the following values

P ¹ : 0.1 MPa

P ² : 0.3 MPa

*A 30% safety margin has been added.

Filling the System (Primary Circuit)

1. Check and charge expansion vessel.

2. Check all connections including factory fitted ones are tight.

3. Insulate pipework between cylinder unit and outdoor unit.

4. Thoroughly clean and flush all debris from the system.

(see section 4.2 for instruction.)

5. Fill cylinder unit with potable water. Fill primary heating circuit with water and

suitable anti-freeze and inhibitor as necessary. Always use a filling loop with

double check valve when filling the primary circuit to avoid back flow

contamination of water supply.

6. Check for leakages. If leakage is found, retighten the screws onto the

connections.

• Anti-freeze should always be used for packaged model systems (see sec-

tion 4.2 for instruction). It is the responsibility of the installer to decide if anti-

freeze solution should be used in split model systems depending on each

site's conditions. Corrosion inhibitor should be used in both split model and

packaged model systems.

Figure 4.3.3 shows freezing temperature against anti-freeze concentration.

This figure is an example for FERNOX ALPHI-11. For other anti-freeze,

please refer to relevant manual.

• When connecting metal pipes of different materials insulate the joints to pre-

vent a corrosive reaction taking place which will damage the pipework.

CAUTION: DRAINED WATER MAY BE VERY HOT

1. Firstly to eliminate any air in heat pump unit pipe works, engage the DHW pump circulator for 1-2 mins and expel any trapped air via nearest hot water tap so as unit be-

comes fully primed/water charged.

2. Before attempting to drain the cylinder unit isolate from the electrical supply to prevent the immersion and booster heaters burning out.

3. Isolate cold water feed to DHW tank.

4. Open a hot water tap to allow draining without creating a vacuum.

5. Attach a hose to the DHW tank drain cocks (No. 22 and 23 on Figure 4.3.4). 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.

6. When the DHW tank is drained close drain cock and hot tap.

7. 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.

8. Water remains in the strainer still after the cylinder unit was drained.

Drain the strainer by removing the strainer cover. (No. 12 on Figure 3.1)

: Water expansion coefficient

: at 70°C = 0.0229

Expansion vessel sizing

7. Pressurise system to 1 bar.

8. Release all trapped air using air vents during and following heating period.

9. Top up with water as necessary. (If pressure is below 1 bar)

10. After removing the air, automatic air vent MUST be closed.

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