Solar Maintenance

Provided some simple maintenance is carried out, the expected life of a solar water heating system is in excess of 20 years and we have seen many examples to prove this.

The following is a maintenance and trouble-shooting guide primarily for owners of our new systems but it could also be used as a basis for other types. For older systems which have an incomplete service history, we recommend an initial inspection by an experienced, competent solar engineer followed by an overhaul if necessary.

ANNUAL INSPECTION (USUALLY BY OWNER)

Externally observed from ground (possibly using binoculars)

1. that the glazing seals are weathertight and sound
2. that all insulation is firmly attached
3. that there is no evidence of serious corrosion or persistant condensation
4. that all covers, fixing screws, etc., are in place and the panel is secure
5. that the anti-bird wires are in place (if fitted)
6. that the panel sensor is secure in the pocket provided
7. that the automatic air vent (may alternatively be in loft) shows no leaks and the dust cap is on

Internally

1. that all air has been expelled from the system (none observed in flow-meter window or audible in pump)
2. that all insulation is firmly in place
3. that there is no damage to pipework
4. that there is no evidence of leaks
5. that the system is at the correct pressure (for sealed systems aprox. 1 Bar)
6. that electrical controls and operational indicators are working correctly (see separate DTC manual)
7. that the sensors are securely fitted into the pockets provided in the cylinder
8. that all components are securely fixed and that all covers, fixing screws, etc., are present
9. that the pressure relief valve releases fluid when briefly twisted

Any points arising from above should be dealt with by a competent person.

EVERY 5 YEARS - TEST ANTIFREEZE (BY COMPETENT PERSON)

The heat transfer fluid may be tested by placing a sample volume into a freezer compartment and measuring the temperature at which the sample becomes 'slushy'. This temperature must be lower than the normal low temperature expected in the locality. A more accurate testing requires the use of a refractometer which we can offer both on-site or by mail.

A sample volume is taken either at the bleed point on the pump (requires a one pence coin or screwdriver to open) or from the drain-point in the airing cupboard. This sample can be mailed in a small darkened container (such as a film canister) for testing. Please ensure the surfaces near the sample point are clean and dry and that the canister is filled to the brim and mailed without delay. Check system pressure after sample is taken.

Except under fault conditions the system should not need draining down for up to 20 years.

PRESSURE LOSS

The pressure in the system may show a slight fall after the initial period of operation. This is normal as the aerated water gives off its dissolved gases. Under normal operation the expansion vessel or make-up cistern will make up for any pressure loss due to aerated solution or gassing. However, if there is a significant drop in pressure or fluid level suspect one or more of the following:

• Overheating may occur during a period of hot weather if, for some reason, the pump isn't operating, and the heat transfer fluid is therefore not being circulated (e.g. during an extended power cut, or during a period of absence, holiday, etc.). Thermal energy is not being removed from the collector so the water temperature will rise, hence water volume and system pressure will increase. This could result in the release of hot water or steam from the pressure relief valve or the automatic/manual vent. When the system returns to normal operating conditions the pressure will reduce due to the loss in fluid volume.

• If water is escaping from the system the volume of water in the system decreases and hence the pressure/fluid level will drop. If there is a leak in the system it may require a drain down and repair/replace faulty component.

• It is unlikely that an expansion vessel (if fitted) will develop a fault. The vessels are normally factory charged to 0.5 bar and should be double-checked prior to installation. They can be rechecked, if suspect, with a standard tyre gauge by removing the black cap on the end of the vessel. This test should only be carried out when the system is cool as there is a danger of scalding should the vessel be faulty. Any fluid escaping from the test valve indicates a leaking diaphragm and the vessel should be replaced.

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