How to select a control panel for an RO plant
Short answer: You need three details to select a panel — how many pumps it must run, the HP of each, and the phase (single or three). The Astero model number tells you this directly: 11NXT means both pumps single phase, 13NXT means raw water single and HP pump three phase, and 33NXT means both three phase.
Once you understand that, selection becomes straightforward. Below is the full chart and the mistakes we see most often.
How to read the model number
The digits in the name indicate the phase of each pump:
| Name | Meaning |
|---|---|
| 11NXT | Raw water pump single phase, HP pump single phase |
| 13NXT | Raw water pump single phase, HP pump three phase |
| 33NXT | Raw water pump three phase, HP pump three phase |
| 333NXT | Three pumps — RWP, HPP and a transfer or circulation pump, all three phase |
The full range
| Model | RWP | HPP | Price |
|---|---|---|---|
| ASTERO 1MP | Single pump, 1 phase up to 2HP | ₹4,095 | |
| ASTERO 3MP | Single pump, 3 phase up to 3HP | ₹6,615 | |
| ASTERO LITE NXT | 1Ph 1HP | 1Ph 2HP | ₹4,704 |
| ASTERO SA11 | 1Ph 2HP | 1Ph 3HP | ₹7,875 |
| ASTERO SA13 | 1Ph 2HP | 3Ph 5HP | ₹9,240 |
| ASTERO SA33 | 3Ph 5HP | 3Ph 5HP | ₹11,025 |
| ASTERO 11NXT | 1Ph 2HP | 1Ph 3HP | ₹9,450 |
| ASTERO 13NXT | 1Ph 2HP | 3Ph 5HP | ₹10,500 |
| ASTERO 33NXT | 3Ph 5HP | 3Ph 5HP | ₹12,600 |
| ASTERO 33NXT 7.5HP | 3Ph 5HP | 3Ph 7.5HP | ₹13,650 |
| ASTERO 33NXT 10HP | 3Ph 5HP | 3Ph 10HP | ₹14,700 |
| ASTERO 333NXT | Three pumps, all 3 phase | ₹18,375 | |
The complete list is in Astero controllers — over 38 models.
SA series vs NXT series
Both do the same basic job, but the NXT is newer and offers more:
| Feature | SA series | NXT series |
|---|---|---|
| Price (the 11 model) | ₹7,875 | ₹9,450 |
| Display | Basic | Better, more information |
| RS485 option | No | Yes (₹2,625) |
| Remote monitoring | No | RM version available |
Our advice: the difference is only ₹1,575. If there is any prospect of automation or remote monitoring later, take the NXT — moving from SA to NXT afterwards means replacing the whole panel.
By plant capacity
| Plant | Typical pumps | Panel |
|---|---|---|
| 250–500 LPH | Both single phase | LITE NXT or 11NXT |
| 1,000 LPH | RWP 1Ph, HPP 1Ph | 11NXT |
| 2,000 LPH | RWP 1Ph, HPP 3Ph | 13NXT |
| 5,000 LPH | Both 3Ph, 5HP | 33NXT |
| 10,000 LPH | HPP 7.5–10HP | 33NXT 10HP |
| Large plus transfer pump | Three pumps | 333NXT |
What the panel actually does
- Dry run protection — stops the pump when the tank empties. Full details in our dry run guide
- Automatic sequencing — the RWP starts first and the HPP a few seconds later, so the pumps are not shocked
- Stops on tank full — via a level switch
- High and low pressure protection — via pressure switches
- TDS or conductivity display — on some models, with a sensor
What the WTP version is
Some models carry the WTP designation, such as the ASTERO 33NXT WTP (₹12,600). This is a configuration for a complete water treatment plant, which also handles filter and softener sequencing rather than RO alone.
Four common mistakes
- Ordering without confirming the phase — an 11NXT supplied in place of a 13NXT will not run the HP pump at all
- No margin on HP — a panel rated exactly for a 5HP pump is fine today, but if the pump is ever upsized the panel has to change too
- Ignoring the cut-out size — if it must fit an existing board, the size matters. 190Hx222V and 305Hx225V are different
- Buying only the panel and no protection devices — a panel cannot prevent dry running by itself; a pressure switch or level switch has to be fitted
What to tell us when ordering
- How many pumps — two or three
- The HP and phase of each pump
- Any limit on the cut-out size
- Whether remote monitoring or RS485 is required
Let us confirm your panel
Send the HP and phase of both pumps and we will confirm the correct Astero model with a GST quotation.
💬 WhatsApp par poochhein 📞 9910646957Frequently asked questions
What is the difference between an Astero 11NXT and a 33NXT?
The digits indicate the phase of each pump. On the 11NXT both pumps are single phase, while on the 33NXT both are three phase. In between there is the 13NXT, where the raw water pump is single phase and the high pressure pump is three phase.
Which panel does my RO plant need?
It depends on the pumps rather than the plant capacity. Check the HP and phase of your raw water pump and high pressure pump, then select accordingly. Smaller plants usually take an 11NXT and larger ones a 33NXT.
Is the SA series or the NXT series better?
The NXT is newer, with a better display and an RS485 option. The price difference is small, so if there is any chance of automation or remote monitoring later, the NXT is the better buy.
Will the panel prevent dry running on its own?
The panel includes the protection function, but it needs a pressure switch or level switch connected to work. Buying the panel alone will not achieve it, so order the switches at the same time.
Why does the cut-out size matter?
If the panel has to fit into an existing board, its cut-out size must match. Astero models are commonly 190 by 222 or 305 by 225, which are quite different. Measure your board before ordering.