The Rinnai MECS (Manifold Electronic Control System) is a totally integrated sequencing system unique to Rinnai, designed for use with internal Rinnai gas water heaters manifolded together in parallel. Water heaters can be linked in this way — up to 25 units in a full system — to deliver a greater hot water flow rate than any single unit could provide on its own.
The REU-MSB-M kit fits inside the first unit, with a master communication PCB and sub-communication PCB installed together, while each subsequent unit only needs the sub-communication PCB and a slave cable. The master board receives flow rate information from every connected unit's PCB and electronically balances the load between them, turning each heater on as required rather than always relying on the same appliance.
Beyond load balancing, the system includes built-in fault detection: if one unit in the manifold fails, the master control automatically allocates a replacement unit to keep the hot water supply running. The kit includes the control board, two connector cables and the mounting hardware needed to connect two internal units (master plus one slave).
Built-in fault detection genuinely sets MECS apart from simple parallel manifolding — if one unit in the system fails, the master control automatically brings another unit online to maintain hot water supply, rather than the system quietly losing capacity. Balancing load across units also reduces unnecessary gas consumption, since additional units only fire when flow demand genuinely requires it.
Order the Rinnai MECS Electronic Sequencing System (Master + 1 Slave) online today.
| Brand | Rinnai |
|---|---|
| Product Code | REU-MSB-M |
| Product Type | Manifold Electronic Control System (MECS) |
| Configuration | Master + 1 Slave |
| Compatibility | Internal Rinnai Gas Water Heaters |
| Maximum System Size | Up to 25 Units (with Additional MECS Components) |
| Function | Load Balancing, Sequencing, Fault Detection |
| Kit Contents | Control Board, Two Connector Cables, Mounting Hardware for 2 Internal Units |
| Mounting Location | Inside Rinnai Infinity Unit |
