Replacing a Fleck 2900 Control Valve June 5, 2023 11:29

The Fleck 2900 is a very popular commercial water system control valve and is widely used across the world. Here's a photo that shows the basics (rear view):

fleck 2900S water softener control valve

Aquatell sells replacement parts and complete replacement control valves for Fleck 2900 and we ship these worldwide. There are a few things you'll need to figure out about your existing Fleck 2900 control valve if you want to order parts for it, or if you want to replace it outright.

Is Your Fleck 2900 a Softener or a Filter?

There are two basic models of the 2900 control valve. One is used for water softeners and one is used for backwashing filters. Usually, the obvious difference between these two applications is the presence/absence of a brine tank (aka salt tank). If there's a brine tank, you've likely got a softener. And even if it's not a softener, if there's a brine tank, you need the "water softener" version of the valve. If there's no brine tank, it's a filter. The photo below shows the brine line which will only be present on a system that has an attached brine tank. If you see this, you need the water softener version of the Fleck 2900 control valve:

Fleck 2900S water softener control valve showing brine line

Does it have Hardwater Bypass?

The Fleck 2900 softener valves comes in two main configurations: Hardwater Bypass or No Hardwater Bypass. These are often abbreviated at HWBP and NHWBP. The "hardwater bypass" version of the valve will allow untreated water to pass through the system if water is demanded while the system is in regeneration mode.  The "no hardwater bypass" version will not allow any water to flow to service while the system is in backwash. Essentially, this system will shut down the water flow completely until the regeneration process is complete. The "no hardwater bypass" version is typically used when the softener is a dedicated pre-filter to another piece of equipment, such as a reverse osmosis system.  When the softener is being used to supply soft water to a mixed-use building, the "hardwater bypass" version is typically seen.

If you're unsure of what you are replacing, looking at the sticker label on the control valve can be useful:

fleck 2900 water softener control valve label sticker

  1. This shows us the model and the type of piston. When "STANDARD" is the piston type this is the "hardwater bypss" version.  For "no hardwater bypass" it will show NHWBP for the piston type
  2. This is the serial number and may be able to be used to discern certain details about the control valve if you contact Pentair.
  3. This shows how the valve has been set up in terms of the Brine Line Flow Control (BLFC) and the Injector (in this case, BLFC = 2.0 and Injector = 4). These components are matched to the tank size.

If you'd like help figuring out what you've got and what you need to replace it, please feel free to contact us. Photos are very helpful.