There are two versions of the DELTA. The standard most common connects to a single mains water tap. The water passes through the Condensers to condense the steam and then feeds into the Boiler/Boilers to be boiled to produce the steam, with the excess then running to waste.
The DUAL FEED version has uses 2 DIFFERENT water supplies. One is mains tap water which only feeds through the Condensers to condense the steam and then straight to waste. The second water supply is trickle feed into the Boiler or Boilers to be boiled and produce steam. The flow rate of the trickle fed water is only slightly lower than the production rate of distilled water.
Both versions of the DELTA can be configured at any time by the owner to produce 6L/hr Single Distilled Water or 3L/hr of Double Distilled Water.
The DELTA and be run with a single Boiler to produce 3L/hr Single Distilled Water even while one Boiler is being cleaned.
The DUAL FEED version distillate quality is better than the standard version because the feed water being distilled is already purified water from a Still/Deioniser/RO System. If the DUAL FEED Still is fed from a rainwater tank only then the water quality will possibly be not as pure as that from a pre‐treated supply but should be purer than from normal tap water in the standard DELTA ERG3.
People choose the DUAL FEED version because they require the highest possible purity distillate. The distillate quality varies depending on the feed water quality and weather Single or Double Distillation is being used.
The ERG4 DUAL FEED version uses more water than the standard version because the cooling water from the mains supply is exactly the same flow rate as the standard RG3 plus the trickle fed Boiler feed water.