A generator that starts reliably in February can fail to carry its load in August. Across most of the Kingdom, summer ambient temperatures sit well above the reference conditions that engine and alternator ratings assume, and generator enclosures run hotter still. Preventive maintenance at this time of year is therefore less about routine and more about margin: keeping enough cooling, air and fuel quality in reserve that the set can still deliver when the grid drops.
Heat reduces the power a generator can deliver
Manufacturers publish derating curves showing how much output a generator set loses as ambient temperature and altitude rise above its rated conditions. A set that was sized with little headroom can trip on high coolant temperature, or fall short of its nameplate output, on the hottest afternoons. Before summer, site loads should be compared against the derated capacity of each set, not the nameplate figure. Where the margin is thin, the options are load management, a larger unit, or a temporary rental generator during peak months.
The cooling system needs the closest attention
Most summer failures we see begin in the cooling system. Fine dust and sand build up in the radiator core and cut airflow long before the blockage is obvious from a distance. A thorough summer check covers:
- Radiator and charge-air cooler cores cleaned from the clean-air side, with fins straightened where damaged
- Coolant level, concentration and condition tested against the engine maker's specification
- Fan belts, fan guards and hoses inspected for cracking and correct tension
- Enclosure louvres and canopy openings cleared so hot air leaves the enclosure instead of recirculating
Air filters clog faster in dusty seasons
Restricted intake air raises exhaust temperatures and fuel consumption, and it shortens engine life. Filter service intervals written for clean environments are rarely adequate for desert sites. Restriction indicators should be read on every visit, and intervals shortened after dust storms rather than waiting for the next scheduled change.
Fuel quality and storage
Diesel stored for long periods degrades, and day-to-night temperature swings draw moisture into tanks, where it condenses. Water in fuel promotes microbial growth and damages injection systems. Tank sumps should be drained of water regularly, filters and water separators replaced on schedule, and long-stored fuel tested. Where generators run as prime power, refuelling logistics become part of reliability: a full tank and a planned delivery route are as important as a healthy engine.
Starting batteries and chargers
High temperatures shorten the life of lead-acid starting batteries, and a battery that tests well in spring may not crank an engine by midsummer. Battery voltage, terminal condition and charger output should be checked on every preventive visit, and starting batteries replaced on a planned cycle instead of after a failed start.
Light loading and exercise runs
Standby generators that only run off-load, or at very light load, can suffer wet stacking: unburnt fuel and carbon accumulate in the exhaust system and reduce performance. Periodic runs under meaningful load, or load bank testing where the site load is too small, keep the engine in good condition and prove that the set can carry its load before an outage tests it for real.
Turning checks into a schedule
An effective programme combines remote monitoring of alarms and running hours, monthly site checks, and service intervals based on the manufacturer's recommendations adjusted for local conditions. Every visit should close with a report and photographs, and repeat faults should trigger a root-cause review rather than another identical repair.
BM maintains prime-power and standby generators for telecom operators and critical facilities across all regions of the Kingdom, supported by our own overhaul workshop and a fleet of rental generators from 20 to 500 kVA.