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Rebuilding the Autotrol 155 ( 1550-TC ) Valve Body

The expected life span of the Autotrol softener control valve is 20 - 30 years with a few minor repairs along the way. The Flapper Valve Discs in the valve body generally need replacement after 15 - 20 years. However, if your system is on a chlorinated water source, the Flapper Valves ( part # 155A152 ) will need replacement much sooner ( 5 - 10 years is common ). On chlorinated water supplies it is also necessary to replace the Flow Control Ball ( part # 4F ) which sits inside the Backwash Plug on the right rear of your valve. In severe cases it made be necessary to replace the injector ( # 28F-BB ) also. There is no need to change other parts or o-rings unless you have a leak.

Autotrol Flapper Valve Positions

The flapper valve discs can be replaced by removing the 11 screws holding the top plate on ( you need to remove the cam and the timer housing first ). The flat springs pop out of the top of the valve discs. A pair of needle noses pliers helps with removing the springs ( and popping them back in place ), and also with pulling the valves out of the valve body. It is a fairly simple procedure.

You can reference this Youtube Video

For Full length ( original - slightly dated ) Manufacturer Service Video for Model 155, 
see = 
Series 155 Control Valve Operation & Maintenance

PLEASE check carefully that the area where the valve disc "seat" is 100% clean, and be sure to Install the Discs into the Valve Body, and THEN lower the Top Plate on top. The Valve Discs must all be INSTALLED and SEATED first, for best possible results ( less chance of problems or leaks ).

The only other "tricky" part is to be careful putting the 11 screws back in. The screws are self tapping. I recommend turning them slowly in reverse until you feel them drop into the thread groove, then alternate tightening them down. Do not over tighten, since you are screwing metal into plastic.

Autotrol 155 Valve Body Rebuild Kit:

1) Set of Flapper Valve Discs part # 155A152
1) Injector part # 28F- AA, BB, or CC ( based on tank diameter )
1) Brine Control part # 1F-19
1) Backwash Plug part # 25F- # 7 - 14 ( based on tank diameter )
2) Flow Control Balls part # 4F
1) Tank Adapter O-rings ( 32F,(4)35F,37F ) part # 150A129
1) Silicone Lubricant 1 gram

NOTE - Does NOT include the
Injector Screen & Cap part # 7F, or the 8F-BB Injector Cap as these are obsolete items we no longer have.. and not in this rebuild kit.

A much easier solution is to purchase the Upper Valve Body ( comes with all new internal parts ),
either with a new 460TC timer and Camshaft as the K-5
or just the complete upper valve body as the 24NC.

Not only does this save a lot of work, it upgrades your valve body to the new 255 design. The flow rate is higher and some of the parts are beefed up to last longer than they did on the 155 version.

440 Timer Repairs

An obvious problem that can occur is for the timer motor to fail. The motors turn at 1 rpm, so it is quite easy to tell if it is turning. A more common problem is for one or more of the drive gears to strip. Removing the Tripper Arm screw, the Skipper Wheel screw and the three cover plate screws will gain you complete access to all components for careful examination. It is easier to work on your timer housing is you remove it from the valve body ( pull out "flag locking pin, slide power cord out of it's retaining slot, unscrew Cam Shaft Bearing at rear of Cam Shaft, and then pull housing straight up )

Common Gears that Fail
1. Tripper Arm Gear # 99F ( 1031756 )
2. # 7 Black Gear # 420A43 ( 1031554 )
3. Red Knob Gear # 106H ( 1001582 )
4. #8 Black Gear # 420A44 ( 1030844 )

Also the "Out Put Connector" # 21E ( 1031496 ) which attaches to and drives the Cam Shaft can crack or break. On rare occasions the Camshaft # 21F-3 ( 1031950 )will break at one end. Also, rare is a cracked Skipper Wheel # 14F-6 ( 1031740 ). Close examination of both sides of the Skipper Wheel is required to detect this failure.
And last, but not least, you can have a gear post break in the housing body it's self. The "Empty 440 Case" # 90F ( 420N66 ) is NO LONGER available ( only the 440i version Backplate, but it can NOT be used with older 440 parts ),
So it is simpler and prudent to replace the Complete Timer Assembly ( with the 440IHV ) at this point.
A complete replacement is also prudent if the unit is over 20 years old.
NOTE: There are no 440 Timers left, and we recommend using the NEW version = 460TC as a replacement.

Products [27]

OBSOLETE - None Left
OBSOLETE - None Left
Must order Individual Injector AA,BB,CC,DD
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