Timed vs Metered Regeneration

Water softeners cannot monitor water hardness, which basically means another method has to be found to determine the appropriate time to regenerate. Typically, if the water hardness of the input water is known, the size of the resin bed is known, and the expected usage is known it is possible to calculate an approximate time between regenerations in terms of litres of water (i.e. n litres will exhaust the bed) or time (i.e. the bed will exhaust every n hours). It is key, in terms of properly setting up a softener that the level of hardness is known and that this is occasionally monitored. It's not uncommon for water suppliers to alter the blending of their water from time to time (usually based on what resources they have available at any given time of the year), so if it rises or drops signficantly the configuration may require adjustment.

Timed Regeneration

These valves are useful in applications where water usage is consistent and there is a window of opportunity to regenerate when no water is being demanded. Time regenerated machines will trigger on pre-programmed days regardless of the amount of water being used. For this reason, it's clearly not desirable to use such a machine in environments where water may be used in vastly different quantities each day - especially larger machines where salt and water usage for regeneration may well be fairly significant.

Timer softeners can be set up as follows:

• Once per day
• Once every other day
• Every 3rd day
• Every 4th day

The "regeneration days" on mechanical softeners (most timer valves are mechanical) are set by a sliding pin out from a series of 12. By adjusting the pins you can 'program' the softener to regenerate the resin bed on the same set of days in any 12 day period.

Electronic valves are actually a little more restrictive - Valves such as the Fleck SE series only allow regeneration on a consistent cycle pattern i.e. every day, every other day - You cannot automatically regenerate in a non-standard pattern as you can with a timer controlled valve.

With a timer valve the softener will always reset at a set time of day on any day it is scheduled to regenerate. This means if you set it to regenerate at 2am in the morning when demand may be lower the softener will always regenerate at 2am.

Metered Regeneration

As the name implies a metered valve measures the amount of water being used so the regeneration is usually far more accurate. If you don't use water for a week the softener simply will not regenerate for that period unlike a timer valve which will trigger regardless. Where water usage is unknown, sporadic or quite varied this presents a more economical solution. The system is a bit dependent on calculating a regeneration point i.e. a volume of water which will exhaust a fresh resin bed, however, this can be easily determined if the water hardness and the size of the resin bed are known. The regeneration of a metered machine can be programmed in two ways

• Immediate
  When the capacity of the machine has been used up the machine will automatically go into it's regeneration cycle. The softener can be fitted with or without a bypass piston (if a bypass piston is installed untreated water will be allowed to pass through until the softener has completed it's regeneration cycle).
  
  
• Delayed Regeneration
  When the capacity of the resin has been used up the machine will automatically go into it's regeneration at a set time pre-determined by the user (i.e. usually a period later on when there is little demand for water). This delay before regeneration can be allowed for in the calculations by estimating a reserve volume of soft water which is likely to cover the period from the capacity