Solar water heater FAQ for Patna

Begin near 25–35 litres of stored hot water per person per day, then correct for baths, showers, kitchen, peak timing, inlet temperature and distribution loss.

Neither is universally better. ETC often lowers entry cost; FPC is robust and useful for engineered arrays. Pressure, water quality and service decide.

Yes on sunny winter days, but output falls with fog, cloud, wind and low irradiation. Correct storage and approved backup cover low-sun periods.

The collector does not heat at night. The insulated tank stores daytime heat; backup may maintain temperature when storage is insufficient.

Only a system and tank rated for the operating pressure should be connected. Use the required PRV, relief valve, expansion control and approved layout.

Select SS grade, GI or glass-lined MS after reviewing water chemistry, pressure, fabrication, anode strategy, warranty and service—not by material name alone.

Hardness can cause scale; chlorides and TDS can affect corrosion. Test water and plan tank protection, anode inspection, flushing or an indirect loop.

A preliminary FPC allowance is roughly 2 m² collector aperture per 100 LPD plus tank, spacing and access. ETC layouts vary by tube bank.

A shade-free orientation near true south is commonly preferred in Patna, with tilt and azimuth finalised from roof constraints and annual/seasonal goals.

Yes when safely designed with thermostat, high-limit cut-out, earthing, MCB/RCCB and dry-heating protection. Large plants may use heat pumps or other backup.

Possible causes include shade, air lock, scale, leakage, high demand, insulation loss, reversed flow, pump/sensor failure or incorrect settings.

Inspect at least annually and more often where water is hard, dust is heavy or the plant is critical. Follow the manufacturer and site AMC plan.

Usually yes with the correct approved size and seal after cooling, isolating and safely draining the system. Avoid working on a hot pressurised roof.

Do not assume it. Verify a current notified programme and eligibility in writing; rooftop-PV support does not automatically apply to water heaters.

Warranty varies by make, model and component. Separate tank, collector, tube, pump, controller, heater and workmanship warranties in the quotation.

A site-ready domestic system may take about a day; commercial plants depend on structure, lifting, piping, controls, civil work and shutdowns.

Receive invoice, make/model list, data sheets, certificates, warranty, drawings, test records, serials, operating instructions and service contacts.

An AMC creates scheduled inspection, cleaning and performance records. Included spares and emergency response must be stated explicitly.