How to Assemble a Clack Valve Head
Installation How-To
How to Assemble a Clack Valve Head
A step-by-step guide to putting together the Clack control valve that ships with your non-backwashing acid neutralizer, carbon filter, or backwashing iron filter. It takes about five minutes, and you do not need a single tool.
The short version
To assemble a Clack valve head: seat the snap ring in the lower groove and the O-ring in the upper groove on each connector, slide the connectors into the back of the valve, and hand-tighten the connecting nuts. Never use a wrench, because over-tightening cracks the plastic and you will have to buy a new part. Press the upper distributor basket onto the bottom of the valve, then thread the head onto the tank. No Teflon tape is needed, every Clack valve seals with an O-ring.
Before you pour media in, tape off the center distributor tube so no calcite or carbon falls inside it. The same valve is used on our non-backwashing acid neutralizers and non-backwashing carbon filters, so this process is nearly identical no matter which system you ordered.
Can you assemble this yourself?
Answer two quick questions to see how ready you are.
1. Do you have painter's tape and a funnel on hand?
What comes in the box
When your non-backwashing carbon filter or acid neutralizer arrives, the valve assembly ships in pieces. Here is what you get:
- The valve head itself (the Clack control valve)
- Two connectors (two 90-degree elbows) that go into the back of the valve
- A bypass with two red knobs that turn the system on and off
- An upper distributor basket that snaps onto the bottom of the valve and keeps media from escaping the tank
People call us about this constantly, so we filmed the whole thing. The same Clack valve is used across our systems, which is why this guide applies whether you bought an acid neutralizer, a carbon filter, or an iron filter.
Step-by-step: assembling the valve head
Filling the tank with media
Before the head goes on, you fill the tank with media (calcite for an acid neutralizer, carbon for a carbon filter). With any water filtration tank filled from the top, there is one step you absolutely cannot skip:
Once the tube is taped off, set your bowl funnel on top and pour the media into the tank. When the tank is full, pull the tape off the tube and you are ready for the head.
Threading the head onto the tank
A question we get on almost every call: do I need Teflon tape on the threads? The answer is no. Every Clack valve seals with an O-ring inside the head, not with thread sealant.
- Give the head a little tap to seat it past the O-ring inside.
- Gently start the thread by hand. Do not cross-thread it, or you will damage the fitting and need a new one.
- Bring it all the way around until it reaches a stopping point.
- Grab it and snug it up by hand. On a 2.5 cubic foot non-backwashing acid neutralizer, the fill port usually ends up on the side.
The bypass and flow direction
Once the head is on, you mount the bypass. The arrows on the bypass pop off and flip, so you can set the flow direction to match your plumbing. The connectors rotate a full 360 degrees, which makes it easy to point your in and out lines wherever you need them: up, down, left, or right.
On a non-backwashing upflow system, water comes in through the upflow side and leaves through the outlet to your main house line. Turning the red knobs the opposite direction puts the system into bypass, so raw water skips the tank.
Non-backwashing vs backwashing bypass
| Feature | Non-backwashing (AN, carbon) | Backwashing (iron filter) |
|---|---|---|
| Bypass type | Plastic bypass, two red knobs | Stainless steel bypass, single lever |
| How to bypass | Turn the red knobs the opposite way | Move the lever arrow to "bypass" |
| Flow direction | Follow upflow in / outlet out | Follow the arrows: arrow in, arrow out |
| Drain line | None needed | Required for backwash |
Want the full breakdown of why these two designs exist? See our guide on backwashing vs non-backwashing acid neutralizers.
What to do after installation
This is where non-backwashing and backwashing systems split:
- Non-backwashing system: nothing to program. Once it is plumbed in and water is flowing through the tank and back to the house, you are done.
- Water softener: program the capacity, the time of day, and the hardness level. Leave every other valve setting alone.
- Iron filter: it comes pre-programmed. Just set the time of day.
- Backwashing acid neutralizer: set the time of day. You only enter the master program if you want to change the backwash days.
For the full plumbing walkthrough by system type, see our guides on installing an acid neutralizer and installing an iron filter.
The system shown in this video
Clack 2.5 Cubic Foot Non-Backwashing Acid Neutralizer
No electricity, no drain line, no backwashing. Corrects low-pH well water (4.0 to 6.9) with natural calcite media. The same Clack valve assembly covered in this guide.
Frequently asked questions
Do I need Teflon tape on a Clack valve?
No. Every Clack valve seals with an O-ring inside the head, so you do not use Teflon tape or any thread sealant. Just tap the head past the internal O-ring, start the thread by hand without cross-threading, and snug it up.
Should I tighten the Clack connecting nuts with a wrench?
No. The connecting nuts are designed to seal hand-tight. Putting a wrench on them over-tightens the plastic and cracks the fitting, which means buying a replacement part. Snug them by hand only.
Is it normal for the connectors to wiggle before I tighten them?
Yes. When you first slide a connector into the back of the valve it will wiggle a little. That is expected. It seats firmly once you hand-tighten the connecting nut.
Do I need to program anything after installing a non-backwashing system?
No. A non-backwashing acid neutralizer or carbon filter needs no programming. Once it is plumbed in and water is flowing through the tank and back into the house, the install is complete.
What do I set on a backwashing system?
A softener needs the capacity, time of day, and hardness level. An iron filter comes pre-programmed and only needs the time of day. A backwashing acid neutralizer needs the time of day, and you only enter the master program to change the backwash days.
What is the most common mistake when filling the tank?
Forgetting to tape off the center distributor tube before adding media. If calcite or carbon falls inside the tube, you have to take the tank outside, dump it, and start over. Always cover the tube with painter's tape first.
Reviewed by Aidan Walsh, Mid Atlantic Water
Aidan has spent over 30 years installing and servicing residential water treatment systems. Setting up a system and not sure what to do next? Call Aidan directly at 800-460-5810 and he will walk you through your exact valve and tank.