Hubbard – LiteAir & HCR Range

High pressure cut-out (HP)

– On a Hubbard LiteAir, a tripped HP will stop the compressor. If auto-reset, the unit may try again later. Signs: The condensing unit is very hot, maybe slight humming then cut-out. Check the HP switch setting (should be ~25–28 bar trip for R410A, auto reset a few bar lower) – if it’s constantly cycling near that, there’s an underlying issue. – Condenser fan: ensure it’s running. If the LiteAir has a condenser fan pressure switch (HP fan control), see if that is functioning – it should kick fan to full speed as pressure rises. If fan stays low or off until too late, that control might be mis-set. – Ventilation: If the condensing unit is installed indoors or in a tight space, measure ambient around it – if it’s recirculating hot air, that raises head pressure drastically. Look for an exhaust path or consider ducting the condenser air out. – Refrigerant overcharge: If recently serviced, verify correct charge. Too much refrigerant in a small condenser will push pressures high, especially in cooler weather (overcharged systems trip HP quickly on mild days).

– Immediate action: Clean the condenser coil. Brush off lint, and use coil cleaner if oily deposits present. This one step resolves many HP problems. – Fan repairs: Replace a faulty fan motor or fan speed controller. If the fan uses a pressure switch to stage, you might retrofit a simpler control or direct-wiring the fan for continuous full-speed operation, sacrificing a bit of efficiency for reliability in a hot environment. – If condenser is indoors and heat can’t escape, arrange to duct the discharge air outside or to a larger space. Hubbard LiteAir units can be internally mounted, but the warm air must be channeled away. Installing a duct or grille to outside can dramatically lower the condensing temp. – Refrigerant check: Recover and weigh the refrigerant, then recharge exactly to spec (if weight is known). If weight not given, charge to proper subcooling or sight glass clear. Ensure no air in system – pull deep vacuum. – After fixes, reset the HP (if manual, press button; if auto, it should run). Monitor head pressure during operation to ensure it stays in safe range (with R410A, condensing temp should ideally be <50°C, ~32 bar). If still borderline, consider adding a condenser fan booster (some techs add a second fan or a stronger fan blade) or ultimately a larger condenser unit if the environment is too harsh.

Low pressure / icing issues

– Evaporator coil: check for ice build-up. Hubbard LE units have a de-ice thermostat – if the coil is a block of ice, perhaps the de-ice stat didn’t cut out. Locate it and test its function (put in ice water to see if it opens circuit at the right temp). – Evap fan: Ensure the evaporator fan runs continuously. If it cycles off with the compressor (depending on wiring), that can allow uneven temperatures and icing. Many cellar units keep fans on always. If yours doesn’t, consider adjusting it to continuous mode. – Inspect the expansion device: LiteAir likely uses capillary tubes for simplicity, possibly a factory orifice sized per model. Not much to adjust, but if partially blocked by debris/moisture, it could cause starving and icing. – LP switch: If the LP safety is tripping, note the suction pressure at trip. If it’s cutting out above what you’d expect for a mildly cold coil, could be mis-set or malfunctioning. You can temporarily bypass for diagnostic only (monitoring to avoid deep vacuum) to see if unit then cools – if it does and coil gets very cold, that suggests the LP was protecting from something else (like low charge). – Charge verification: Low charge is very common – check for oil around joints, etc. If the system is low, icing usually starts at the expansion entry point and doesn’t encompass entire coil at first.

– Thaw and dry: Turn off compressor and let the evaporator thaw completely. Use towels to manage water. Do not use open flame or extreme heat – just room air or gentle warm water if needed. – Fix airflow: If the evaporator fan was not continuous, rewire or reprogram it to run constantly (most electronic controllers have a fan mode setting). A continuously running fan also helps melt light frost during off-cycle (off-cycle defrost). Replace any faulty fan motor or blade. – De-ice thermostat: If defective, replace it. If not present and icing is frequent, consider installing one in series with the compressor control. Set it to cut out ~-1 to 0°C evaporator temp. This will stop the compressor for a few minutes to allow ice to melt when detected early. – Dry/filter: If moisture is suspected (icing at expansion could be moisture freezing in capillary), evacuate and install a new filter-drier, then recharge with fresh refrigerant. This will also ensure proper charge. – Recharge refrigerant: Remedy any leaks and weigh in the correct charge. With correct charge, the system should maintain enough pressure to avoid LP trip under normal load. After charging, test low-load conditions to ensure it doesn’t still drop to cut-out (some cellars get very low load at night – if so, adding a small heater load or adjusting cut-out can help). – Reconnect or reset the LP safety after cause addressed. Don’t leave it bypassed – it’s there to save the compressor in case of sudden leak or pump-down. If it was a false trip due to calibration, replace it rather than permanently adjusting it out of safe range.

Electrical or control issues (No cooling but fans run, etc.)

– If the unit’s fans are on but the compressor isn’t, aside from HP/LP switches, consider the thermostat/controller. Hubbard LiteAir might have a digital thermostat. Ensure it is set to cool mode and the setpoint is below ambient. If it has an off-cycle timer, maybe it’s in delay. – Compressor capacitor (for single-phase): a failed run capacitor will prevent the compressor from starting (you might hear a hum then click of overload). Check the capacitor for bulging. – Internal overload: The compressor’s internal protector might have tripped due to prior overheating. If so, the compressor will not run until it cools. This can take several hours. Measure compressor winding resistances – if one reads open, likely internal overload open. Wait and recheck. If it closes after cooling, find out why it overheated (again likely HP issue or low voltage). – Wiring: Inspect all connectors – fans running means some power is there, but a broken neutral on compressor circuit or failed contactor coil could keep compressor off. – Heater stuck: If an internal heater is on when not needed, it could be heating the cellar while the cooler fights it. You’d see simultaneous cooling and heating (inefficient and confusing to diagnose). Check heater relay operation if applicable.

– Thermostat calibration: If the controller is reading way off (say it thinks cellar is 5°C when it’s actually 15°C), replace or recalibrate the air sensor. Temporarily set a very low target to force it on if needed while diagnosing. – Replace capacitor: If the compressor’s run capacitor is bad, install a new one of identical µF and voltage rating. That often revives a “stuck” compressor. Also verify the contactor is delivering voltage and not dropping out (low voltage can cause the contactor to chatter and compressor to stall – if so, trace the electrical supply, possibly a wiring upgrade is needed). – Overload recovery: After an internal overload trip, it’s wise to change the oil or at least ensure the compressor has not been repeatedly tripping (the oil could be overheated). If it’s a hermetic, not much can be done about oil on-site, but let it cool fully and restart. Use an ammeter to ensure it’s drawing normal running current, not over-amping. – Heater control: If your cellar has a cask-ale heater wired in, make sure it’s controlled by a thermostat (some systems use a dual thermostat – one for cooling, one for heating). If the heater was stuck on, you may need to replace its thermostat or SSR. You can disable the heater temporarily by pulling its fuse to see if cooling catches up. Long term, fix the control logic so heating and cooling aren’t competing. – Professional service: If multiple electrical issues are present, have a certified engineer test the system thoroughly – from supply voltage, phase balance (if three-phase), to relay operations. Hubbard units are robust, so if they’re not cooling, often it’s something like a safety engaged or a minor part like a capacitor/contactor failing which is relatively easy to fix.