Filling The System (Primary Circuit); Draining The Hydrobox - Mitsubishi Electric EHSC-VM2B Service Manual

Filling the System (Primary Circuit)

1. Check all connections including factory fi tted ones are tight.
2. Insulate pipe work between hydrobox and outdoor unit.
3. Thoroughly clean and fl ush, system of all debris. (Refer to 4.2 in the installation manual.)
4. Fill primary heating circuit with water and suitable anti-freeze and inhibitor as necessary. Always use a fi lling loop with double check valve when fi lling the
primary circuit to avoid back fl ow contamination of water supply.
• Anti-freeze should always be used for package systems. It is the responsibility of the installer to decide if anti-freeze solution should be used in split systems
depending on each site's conditions. Corrosion inhibitor should be used in both split and package systems.
• When connecting metal pipes of different materials insulate the joints to prevent a corrosive reaction taking place which will damage the pipework.
5. Check for leaks. If leaks are found, retighten the screws on the connections.
6. Pressurise system to 1 bar.
7. Release all trapped air using air vents during and following heating period.
8. Top up with water as necessary. (If pressure falls below 1 bar)

Draining the Hydrobox

WARNING: DRAINED WATER MAY BE VERY HOT
1. Before attempting to drain the hydrobox islolate from the electrical supply to prevent booster heater burning out.
2. Isolate hydrobox from primary water circuit and drain water from hydrobox. Use a suitable heat resistant hose to assist in these operations.
3. Drain any remaining water from booster heater using fi tted drain cock and hose, and the drain valve on the primary circuit to safely drain the unit.
4. After the hydrobox is drained, water remains in the following component parts. Drain water completely by checking the inside of the parts.
• Strainer (Remove the strainer cover.)
• Pressure relief valve (Operate the valve.)
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