Introduction

We’re often asked to comment on two related questions: What is the expected service life of a new Davis weather station and when is it time to consider replacing an elderly Davis station with a new one? This topic addresses both questions.

Expected service life

Inevitably this depends on circumstances to some extent. Sensors at coastal locations and sited so close to the sea that there’s a significant concentration of salt spray in the air will unavoidably age more quickly than those sited inland. And anemometers at exposed hill-top sites with frequent high winds will see more wear than those in more sheltered locations. Maintenance such as regular cleaning of eg the rain gauge and prompt attention to low batteries (to prevent leakage from dead batteries) will also help prolong service life. But insofar as any estimate of average life is possible then here are some background & guidelines:

  • The warranty period for Davis stations bought from ourselves is 2 years (recently increased from one year). This covers faults that might reasonably be attributable to manufacturing defects (and obviously not to eg accidental or lightning damage, which may be insurable separately under your own domestic or commercial insurance policies);
  • A reasonable expectation is that the station might, on average, operate without repairs for about a five-year period. This is not a guarantee – as with all manufactured products, the occasional unit may have a problem within this period; it is simply a statement of typical operating experience;
  • In general terms, it’s usually found that the station components housed indoors in a warm, dry environment can last many years but the outside sensors, especially anemometer and temperature/humidity sensor, will often require or benefit from replacement during the second 5 years (ie the 5-10 year period) of a station’s life;

Overall therefore one might reasonably expect that a new station might have an operating life of up to 10 years, provided repairs are carried out as necessary, especially during the second half of this total period. There’s no sudden deterioration at the 10-year point, indeed we know of quite a number of Davis stations that are still operating successfully at 15 years and more. But at 10 years and older, the technology and specification of a station also becomes progressively more dated, in addition to general ageing of the station.

Remember also that it may be increasingly difficult to source certain spares as the station ages further. Although Davis model designations such as Vue or VP2 have a long production life, the designs regularly evolve and, for example, few of the spares for original Vue ISS models are identical to the latest parts. Davis do have a policy of maintaining a supply of spares for 5 years after production of a given model ends and, in practice, the majority of spares continue to be available for a long time thereafter. But there are sometimes reasons why there is only a finite factory reserve of a given spare (such as the temperature/humidity sensor on an original Vantage Pro model) and once this is exhausted then the spare can become very difficult to source.

When to replace a Davis station

Most Davis stations will give long and valued service, but there will come a point where a replacing the station either completely or in part needs to be considered. This may be because the user prefers to switch to a complete new station with updated specification and technology, and new features. Or, given that the console and logger typically have a longer service life than the outside sensors, it may be that a new ISS unit alone (which is readily available for most Davis stations) might be the most cost-effective solution. Overall there are three further reasons why a full or partial replacement station might need to be considered:

  • The supply of a specific spare might have been exhausted;
  • Cost considerations;
  • Compatibility issues;

The issue of spares availability has been discussed at the end of the previous section above. It is, fortunately, only rarely a problem, but when this issue does crop up it may be very tricky to work around, short of replacing larger parts of the station.

The cost aspect arises because, as with most manufactured products, the cost of supplying individual spare components is high relative to buying them in a complete finished assembly such as the full ISS (which also includes a new anemometer for VP2 models). It’s certainly the case that if only a single component needs replacing then it’s cost-effective to replace just that component. But for an ISS that’s perhaps 7-8 years old (and, as above, it’s usually the ISS or other sensors that this applies to, rather than the usually long-lived console or logger) then inevitably all of the sensor elements will be ageing together. The anemometer bearings will have recorded many millions of cup and vane rotations, the reed switch in the rain gauge may be approaching its service life and so on, and the ISS after many years outside in all weathers will probably no longer look in mint condition cosmetically.

It can, however, be a false economy to replace two or three different spare parts on an ageing ISS (eg the temperature/humidity sensor may need changing now, perhaps a new anemometer might be needed next year, and so on) because the total cost will exceed that of buying the complete new ISS. It is very much the user’s choice as to whether they replace individual sensor parts as required – provided the spares remain available then there’s no reason why this approach cannot continue indefinitely – or decide that a complete new ISS might be a more cost-effective option in the long run. In general, we would suggest that for sensor replacements on an ISS that’s 6-8 years or more old then it’s well worth considering whether or not a new ISS, or indeed a complete new station, might not be a better option.

Compatibility issues must be considered carefully. Although Davis typically keep particular models in production for many years, there can be important changes of specification during that time and newly purchased parts simply may not be compatible with older stations. It’s always a good idea to talk to an experienced dealer before buying a new part just to double-check this aspect. Some examples of major compatibility issues include:

  • Temperature/humidity sensors on 2004/5 era VP2 stations are no longer available and cannot be substituted by the more recent type;
  • There is the ‘green dot’ logger issue, which prevents older Weatherlink loggers being used with console manufactured over the past 2-3 years – see the green dot topic for further information;
  • Original Vantage Pro (VP1) wireless and cabled parts are incompatible with the equivalent VP2 parts. (VP1 stations have now been out of production for over 10 years and the great majority of VP1 components are no longer available. See the VP1 topic for more details.);

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