Industrial Water Softener Maintenance

Res-Kem Corp. and our sister company General Water Services offer preventative maintenance contracts for customers here in the Mid-Atlantic region. I thought it might be helpful to go over our Preventative Maintenance procedures for a commercial or industrial water softener for those of you who maintain your own water softening equipment.

For an industrial water softener we suggest our customers have bi-annual visits by our technicians. It's a very simple inspection that can prevent unscheduled downtime and the associated problems. How often our customer tests the water hardness is largely determined by how critical the application is and the availability of staff. We strongly suggest testing the water hardness on a daily basis if possible.

Res-Kem service technicians do a mechanical inspection that includes the following:
Inlet and Outlet Water Hardness - When we specify a commercial or industrial water softener we are given a water analysis, the average, high and low flow rates, hours of operation, and desired end-point. It's important to note changes against the design specification. If all things are equal, seeing hard water at the outlet points to a mechanical problem with the water softener (or no salt in the brine tank). If something else has changed - flow rate is lower or higher than specified or the inlet water hardness has increased - our technician will review the data with our engineering department and discuss the problem in greater depth with the customer.

Inlet and Outlet Pressures - Pressure testing is done when the water softener is running at the design specification. If there is a high differential the water softener might be running at too high a rate. If the water softener is running at a typical flow rate, (10 – 15 gpm/ft2) and there is a high differential pressure, the resin bed could be plugging up and preventing the water from flowing through the softener correctly. The differential pressure across a softener resin bed should generally run less than 15 psig. Of course there are many factors, which can result in higher differential pressures, i.e. depth of the resin bed, design of the internal distribution, age of resin, etc.

Inlet Chlorine (in absence of carbon filter or bi-sulfite feed) - Chlorine will break down cation ion exchange resin. Exposure to significant amounts of free chlorine, "hypochlorite" ions, or other strong oxidizing agents over long periods of time will eventually break down the crosslinking. Over time the cation resin turns to mush and will plug up the bed or eventually be flushed out so there remains much less resin than required.

Check salt level in brine tank, add if necessary

Make Note of Leaks - Our technicians are trained to look carefully for that small drip. We'll fix it if possible while we're there, otherwise we will make an appointment to come back to service the problem. You should have gaskets in on hand for both the manway and handhole openings.

Make Adjustments to the Control Valve - You should have received an operating manual with the water softener which includes information about the system settings.

If outlet water is out of hardness specification adjustments may be necessary.

Verify water softener timer is set to correct time and day.

Recalculate how often the water softener should be regenerating based on hardness and gallons and adjust control as necessary.

Optional Annual Maintenance

Valve Maintenance - There are many different types of controls and valves used on a commercial industrial water softener. In general you will need the following parts on hand to perform this service:

Aquamatic Valve Nest Systems - Diaphragm & Seal Kits, Internal Parts Kits, Seat Tools and Shaft Tools.

Fleck Top Mounted Control Systems - Upper and Lower Seal & Spacer Kits, Top Piston Kit, Lower Piston Kit.

Autotrol Top Mounted Control Systems - Internal parts kits. Specific kits depend on valve type.

Ion Exchange Resin Test - Although softener resin will last significantly longer than deionizer resin, in the presence of chlorine or other oxidants it will break down. If your water is highly chlorinated or has other contaminants such as iron, you should test the resin within 18 to 24 months of start up and every year thereafter. Otherwise, test the resin after the third year and then every year thereafter. By doing so you will know when to budget softener resin replacement as it is often a major expense.

Triple Softener System for Steam Heat Peaking Plant Sized for 750 gpm Flow

Here is another example of number of the industrial, commercial, residential, and/or residential water treatment systems being designed, assembled, shipped and installed by Res-Kem engineers, pipefitters, and/or contractors within in the past few months.

A Boston steam heating company needed to replace their aging Permutit triple softening system. These units, with Permutit multiport valves, had reached the end of their life.


Res-Kem was selected based upon the recommendation of a sister company in Cambridge, MA which had a Res-Kem triple softening plant at their facility. Since the Permutit multiport valves are no longer commercially available, the Res-Kem design used Aquamatic valves instead of the Permutit valves. Also, it appears the size of the existing Permutit units was too large for the plant flow requirements. Res-Kem used a peak design flow from the softeners of 750 gpm. Upon careful review and competitive bidding process, Res-Kem was selected to provide the replacement system.

Several design changes from the standard Res-Kem industrial softener design were needed to meet the unique requirements of this peaking plant. In particular, the valves needed to be changed from our standard normally open (air to close) actuation to normally closed (air to open) actuation. This was done so the valves will fail closed in the event of loss of air pressure. Normally air pressure is used to stop the water flow during periods of downtime. In this case, when the plant is not being used to generate steam, virtually all power is turned off including tha air compressors to save energy.



With precise drawings by Res-Kem engineers, accurate assembly by Res-Kem pipefitters, and excellent coordination with the site mechanical contractor, the water softeners are being rapidly installed. Commissioning is scheduled for the week of December 15, 2008 only 5 business days from shipment! When our start-up engineer visits for operator training, we will post a picture of the installation.

Water Softener in Steam Plant

Last week, a triple industrial water softener designed and manufactured by Res-Kem was started up in a Cambridge, Massachusetts steam plant. The softener system has an Allen Bradley PLC and PanelView 600 HMI for controlling the automated running and regeneration of the three softeners.

Each of the 48 inch diameter x 72 inch straight-side vessels holds 37 cubic feet of cation ion exchange resin. Careful coordination between A&E firm designing the entire plant and Res-Kem yielded a project that fit into the space and time allotted. The engineer responsible for starting up the entire steam plant stated that the Res-Kem triple water softener was the "best ion exchange system I have ever started up with a great design and excellent construction." The softeners are used to provide makeup to the steam plant.


About the Steam Plant and Network:
This steam plant supplies a steam network near Harvard University and the Massachusetts Institute of Technology (MIT). The steam network supplies process steam to global leaders in biotechnology and pharmaceuticals. The steam network used heavy fuel oil-fired boilers. The new plant now uses new gas-fired steam heating plant with a rated capacity of 110 tons per hour. The new facility will supply 150,000 tons of steam a year to its industrial customers and property owners in the Cambridge region.