Coleman-Mach 9430A751 Cool Only Zone Control Box Assembly

Here's the short version. The Coleman-Mach 9430A751 is a digital zone control box assembly. It sits between your Coleman Mach zone thermostat and your rooftop air conditioners, and it's what lets one thermostat on the wall run multiple units and multiple heating zones from a single spot. This is the cool-only version, so it's built for Coleman Mach cool-only air conditioners. Not heat pumps.

If you've got a larger RV with more than one rooftop AC, you already know the headache of walking front to back adjusting units one at a time. Zone control fixes that. The 9xxx series setup can run up to four rooftop air conditioners plus four zones of gas, hydronic, or electric strip heat, all from one digital thermostat. The 9430A751 box is the hub that makes that possible. It reads the thermostat, talks to each unit, and keeps the zones straight.

One thing to be clear about up front. This is the control box, not the thermostat. You'll need a Coleman Mach 9330A3341 (black) or 9330A3351 zone thermostat to run it, and those are sold separately. If you already have one of those thermostats on the wall and your old control box quit, this is your replacement. If you're building a zone system from scratch, plan on buying both.

The cool-only designation matters, so don't skip past it. This box is wired for cool-only air conditioners. If your rig runs Coleman Mach heat pump units, you want the heat-ready or heat pump version instead, not this one. Matching the control box to the type of AC you actually have is the difference between a system that works on the first try and a service call. When in doubt, check the model tag on your rooftop unit before you order.

Install is straightforward for anyone comfortable working with 12-volt RV wiring. The box mounts inside, typically in a cabinet or ceiling chase near the thermostat run, and wires into your existing AC and thermostat harness. If you've wired a thermostat before, this is familiar territory. If you haven't, it's still a reasonable afternoon project with the Coleman Mach wiring diagram in hand. Take a photo of your old connections before you pull anything.

Who's this for? Owners of motorhomes and larger fifth wheels running two or more Coleman Mach cool-only rooftop units who want single-thermostat control. Anyone replacing a failed 9430A751 box. And folks upgrading an older single-zone setup to the 9-series digital zone control. It's genuine Coleman Mach hardware, so it drops into the ecosystem the way it's supposed to.

A quick word on the two compatible thermostats. The 9330A3341 is the black five-button digital zone thermostat, and the 9330A3351 is its sibling in the same family. Either one runs this control box. They give you a digital readout and per-zone control, which is a real step up from an old mechanical dial. If you're picking a thermostat to go with this box, either model is a correct match. Just make sure you're buying a zone thermostat and not a standard single-zone head.

What it's not: it's not a thermostat, it's not a heat pump controller, and it's not a universal box that works with every brand of RV air conditioner. It's a Coleman Mach part for Coleman Mach cool-only systems. Because it's genuine Coleman-Mach gear rather than a generic aftermarket board, the connectors and logic line up with the rest of your system. That saves you from chasing adapter pigtails or guessing at pin assignments, and it means the full manufacturer warranty stands behind it. We keep these in stock and ship the same day when your order's in before the cutoff, so a dead control box doesn't have to mean a hot weekend waiting on parts.