water pressure control
Building water pressure control means holding the pump's outlet pressure inside a band narrow enough that people in the building feel it as steady.
What is a water pressure control?
Building water pressure control means holding the pump's outlet pressure inside a band narrow enough that people in the building feel it as steady.
HYDROSET PM821 reads the line pressure with a 0 to 20 bar sensor and switches the pump between two set values: F2 is the start pressure and F1 is the stop pressure. The factory values are F1 at 3.0 bar and F2 at 1.5 bar, and both are changed from the display. Because the decision comes from a pressure figure rather than a mechanical spring, the pressure stays even on the upper floors too.
Types and other names
Other names for this device: smart pump controller · automatic pump switch · pump protector · electronic pressure switch · pressure controller
How it works
- The pressure sensor measures the line pressure continuously.
- When the pressure falls to the F2 value, the unit soft-starts the pump.
- When the pressure reaches the F1 value, the unit soft-stops the pump.
- If the pump current rises above F3, or no water arrives, the unit stops the pump and shows a fault code.
Model selection guide
| Pump current | Pump power | Model | Typical use |
|---|---|---|---|
| up to 8 A | up to 1.5 kW | PM821-8 | 1–4 floors, homes and shops |
| 8 – 16 A | up to 3 kW | PM821-16 | 5–10 floors, booster sets |
| up to 25 A | up to 4 hp | PM821-25 | Residential, commercial and agricultural |
The current on the pump nameplate decides the model, nothing else.
Compared with models on the market
Pump controllers are sold in Iran under many names. The table below lists only the verifiable properties of PM821 taken from its manual. No figure and no price is given for any other product, because market prices change quickly and an unsourced claim damages the text's credibility.
| Property | PM821-8 | PM821-16 | Unit |
|---|---|---|---|
| Maximum pump current | 8 | 16 | A |
| Maximum pump power | 1.5 | 3 | kW |
| Peak starting current | 10 | 30 | A |
| Supplied sensor pressure range | 0 – 20 | 0 – 20 | bar |
| Pressure sensor thread | G1/4 | G1/4 | female |
| Input voltage | 180 – 240 | 180 – 240 | V |
| Output voltage | — | — | equal to input |
| Unit's own consumption | < 5 | < 5 | W |
| Operating temperature | -15 – 55 | -15 – 55 | °C |
| Weight, boxed | 650 | 650 | g |
These figures come from the HYDROSET PM821 user manual (hardware A3.3, software 4.0). The manual covers PM821-8 and PM821-16 only, so no column is shown for PM821-25.
Common brands on the market: استریم · JCP · پنتاکس · لوئیز · دلتا / ونزو / وات · آبارا / رویال
Applications
Price and ordering
The price of PM821-8 and PM821-16 is on each product page. PM821-25 is made to order and has no published price; contact the company for it.
Frequently asked questions
What is a water pressure control?
Building water pressure control means holding the pump's outlet pressure inside a band narrow enough that people in the building feel it as steady. HYDROSET PM821 reads the line pressure with a 0 to 20 bar sensor and switches the pump between two set values: F2 is the start pressure and F1 is the stop pressure. The factory values are F1 at 3.0 bar and F2 at 1.5 bar, and both are changed from the display. Because the decision comes from a pressure figure rather than a mechanical spring, the pressure stays even on the upper floors too.
Which PM821 model suits my building?
The current on the pump nameplate decides it: up to 8 A and 1.5 kW is PM821-8, 8 to 16 A and up to 3 kW is PM821-16, and up to 25 A is PM821-25.
Does it work without a pressure vessel?
Yes. HYDROSET PM821 works both with and without a pressure vessel.
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