Pentair SuperFlo Pumps

Older SuperFlo units have no usable bus. They take speed commands as contact closures on four separate digital inputs, which means one pump consumes every dry contact the iSmart Module has. Check the manufacture date before you promise anything.

Work out which pump you have

Pentair changed what these pumps support partway through production. SuperFlo VST and SuperMax VS units built after 15 October 2020 can be driven over RS-485 with the RS-485 Automation Wiring Kit. Everything else — including all earlier SuperFlo VS units — has to be driven by digital inputs.

The wiring kits

Neither method works without one of Pentair's kits, because the pump's communication port is a watertight moulded connector rather than a terminal block. The kit is the cable. Which kit is fitted also decides what the wire colours mean.

Function	Signal range	Kit 353129Z	Kit 356324Z
+5 V output for digital inputs	0-20 mA	Red	Red
RS-485 A	-7 V to +12 V	not present	Yellow
RS-485 B	-7 V to +12 V	not present	Green
SPEED 1 digital input	0, 5-30 V AC/DC	Green	White
SPEED 2 digital input	0, 5-30 V AC/DC	Yellow	Blue
SPEED 3 digital input	0, 5-30 V AC/DC	Orange	Orange
QUICK CLEAN digital input	0, 5-30 V AC/DC	Brown	Brown
Common ground	0 V	Black	Black

Table 1 from Pentair's guide. The two kits reuse green and yellow for completely different purposes.

Driving it from dry contacts

The pump provides its own +5 V trigger on the red conductor. Switch that through the module's dry contacts into whichever speed input you want, using COM and N.O so each contact rests open. An input is asserted while its contact is closed.

The pump's +5 V red conductor feeding the common of four dry contacts on the iSmart Module, each switching one of SPEED 1, SPEED 2, SPEED 3 and QUICK CLEAN. — Four contacts, four speeds. The pump supplies the trigger voltage; the module only closes the path.

If more than one input is asserted at once the pump resolves it by priority: Quick Clean beats Speed 3, which beats Speed 2, which beats Speed 1. That is a useful safety net, not a control strategy — drive one contact at a time.

If the pump does support RS-485

With kit 356324Z on a post-cutover VST or SuperMax VS, only the yellow and green conductors are used and every other conductor is cut back and terminated. Pentair also requires some setup on the pump: program its internal clock, set SPEED 1 to 0 RPM for 24 hours, disable priming so the controller owns it, then put the pump into External Control Only mode.

When it does not respond

Symptom	Where to look first
No reaction to any contact	Start/Stop LED off at the pump, or the red +5 V conductor not landed.
Wrong speed runs	Contacts assigned in a different order from the app, or two inputs asserted at once and priority is choosing for you.
Serial terminals dead after wiring a 353129Z	Green and yellow on that kit are speed inputs, not the data pair. Check what was landed on the PORT.
RS-485 kit fitted but no communication	Pump left out of External Control Only mode, or built before the cutover.

Sources

Pentair, SuperFlo VST / SuperFlo VS / SuperMax VS Installation and User's Guide — Table 1 conductor definitions, wiring kit part numbers, digital input signal range and the 10/15/20 cutover
iSmart Module relay driver board — KiCad schematic and BOM. H1/H2 and AUX1/AUX2 are optocoupled dry relay contacts (N.C / COM / N.O); the four valve relays switch 24 VAC and are not dry