Nocchi DHI Centrifugal Multistage Booster Pumps
The Pentair Nocchi DHI is a horizontal multistage centrifugal pump for clean water at high pressure, including hot water up to 90°C. It is supplied as a bare pump and motor, so you build it into your own booster set, washing system, irrigation line or machine with the controls that suit the job. Every model has 1¼” suction and delivery connections set at 90 degrees to each other, and a 2-pole motor running at 2850 rpm.
Multistage means several impellers on one shaft, each adding pressure in turn, which is how a compact pump reaches more than 60 metres of head. The pump body, impellers and shaft are AISI 316 stainless steel, the motor housing is die-cast aluminium, and the mechanical seal is carbon on ceramic with EPDM gaskets. The motor is IP55 rated with Class F insulation.
How the DHI model codes work
The first figure is the hydraulic family. The DHI 2 pumps are built for lower flows, up to 60 litres per minute, and give the most pressure: the DHI 2-70 reaches 63 metres. The DHI 4 pumps handle up to 120 l/min at more moderate heads. The second figure rises with pressure within each family, so a 4-50 gives more head than a 4-30 at the same flow.
The letter is the supply. M models run on 230v single-phase and T models on 400v three-phase; flow and head are the same for both. At 40 l/min, where the two families overlap, the DHI 2-70 and DHI 4-50 both give 44 metres. Choose the 2-70 if your demand stays below 60 l/min, and the 4-50 if you need to go higher.
DHI or a ready-made booster set?
If you want a plug-in pump for a house, the Pentax PM45-A has its own automatic control built in. The DHI suits installers who are specifying their own controls, need three-phase power, or are pumping hot water.
| Model | Supply | Motor output P2 (kW) | Current (A) | Head at 40 l/min (m) | Highest listed head (m) | Max flow (l/min) |
|---|---|---|---|---|---|---|
| DHI 2-40M (no longer available) | 230v single-phase | 0.40 | 3.2 | 27 | 36 | 60 |
| DHI 2-60M | 230v single-phase | 0.60 | 4.1 | 37 | 53 | 60 |
| DHI 2-70M (no longer available) | 230v single-phase | 0.78 | 5.2 | 44 | 63 | 60 |
| DHI 4-30M | 230v single-phase | 0.50 | 3.6 | 27 | 27 | 120 |
| DHI 4-40M | 230v single-phase | 0.70 | 4.4 | 35 | 35 | 120 |
| DHI 4-50M (no longer available) | 230v single-phase | 0.90 | 5.8 | 44 | 44 | 120 |
| DHI 2-40T | 400v three-phase | 0.40 | 1.4 | 27 | 36 | 60 |
| DHI 2-60T | 400v three-phase | 0.60 | 1.8 | 37 | 53 | 60 |
| DHI 2-70T | 400v three-phase | 0.78 | 1.8 | 44 | 63 | 60 |
| DHI 4-30T | 400v three-phase | 0.50 | 1.7 | 27 | 27 | 120 |
| DHI 4-40T | 400v three-phase | 0.70 | 2.0 | 35 | 35 | 120 |
| DHI 4-50T | 400v three-phase | 0.90 | 2.0 | 44 | 44 | 120 |
Figures are from Pentair’s DHI datasheet. Head for the DHI 2 models is listed from 10 l/min and for the DHI 4 models from 40 l/min, so the highest listed head is not a closed-valve figure. Click through to any model for its full performance table.
Showing 19-30 of 12 results
60 l/min · 36 m · 230v
This product has now been discontinued. Get in touch with us and we can advise you on the best ...Read More60 l/min · 53 m · 230v
Horizontal multistage pump in AISI 316 stainless steel, 230v single-phase, 0.60 kW. Up to 60 l/min, with 37 m ...Read More£523.84 +VAT
60 l/min · 63 m · 230v
This product has now been discontinued. Get in touch with us and we can advise you on the best ...Read More120 l/min · 27 m · 230v
Horizontal multistage pump in AISI 316 stainless steel, 230v single-phase, 0.50 kW. Up to 120 l/min, with 27 m ...Read More£539.02 +VAT
120 l/min · 35 m · 230v
Horizontal multistage pump in AISI 316 stainless steel, 230v single-phase, 0.70 kW. Up to 120 l/min, with 35 m ...Read More£603.88 +VAT
120 l/min · 44 m · 230v
This product has now been discontinued. Get in touch with us and we can advise you on the best ...Read More60 l/min · 36 m · 400v
Horizontal multistage pump in AISI 316 stainless steel, 400v three-phase, 0.40 kW. Up to 60 l/min, with 27 m ...Read More£490.03 +VAT
60 l/min · 53 m · 400v
Horizontal multistage pump in AISI 316 stainless steel, 400v three-phase, 0.60 kW. Up to 60 l/min, with 37 m ...Read More£547.30 +VAT
60 l/min · 63 m · 400v
Horizontal multistage pump in AISI 316 stainless steel, 400v three-phase, 0.78 kW. Up to 60 l/min, with 44 m ...Read More£726.01 +VAT
120 l/min · 27 m · 400v
Horizontal multistage pump in AISI 316 stainless steel, 400v three-phase, 0.50 kW. Up to 120 l/min, with 27 m ...Read More£559.72 +VAT
120 l/min · 35 m · 400v
Horizontal multistage pump in AISI 316 stainless steel, 400v three-phase, 0.70 kW. Up to 120 l/min, with 35 m ...Read More£627.34 +VAT
120 l/min · 44 m · 400v
Horizontal multistage pump in AISI 316 stainless steel, 400v three-phase, 0.90 kW. Up to 120 l/min, with 44 m ...Read More£693.58 +VAT
Where to Use Nocchi DHI Multistage Pumps
The DHI is most often the pump inside a booster set that an installer builds on site: a DHI with a pressure switch and pressure vessel, or with an electronic pressure controller, drawing from a break tank. It suits flats, offices, hotels and workshops where one pump serves several floors. Our guide to low water pressure in commercial buildings covers the pressure needed at the top outlet, and how to choose the right booster pump explains sizing on flow and head together.
Because it is rated for water up to 90°C, the DHI also suits hot water circulation and condensate return, where many cold water boosters are limited to around 50°C. Pentair lists washing systems, garden irrigation, fountains, the food and wine industries, and use as a component in industrial machinery among its applications. The pumped liquid must be clean, without suspended solids or abrasive material.
Mount the pump horizontally in a dry, ventilated room with the suction pipe short and free of air locks. For boosting drinking water in the UK, draw from a break tank or cistern rather than connecting straight to the mains supply pipe, unless your water supplier has approved the arrangement. Our guide on how to read a pump curve helps you find your duty point.
Frequently Asked Questions
Is a Nocchi DHI pump a complete booster set?
No. Each listing is the pump and motor only, with no pressure switch, vessel or controller. To make an automatic booster, add a pressure switch and vessel or an electronic pressure controller from our pump controls range, plus isolation valves.
Can the DHI pump hot water?
Yes. Pentair rates the DHI for liquid temperatures up to 90°C, with a maximum operating pressure of 6 bar at that temperature. Make sure pipework and any vessel are rated to match. The maximum ambient temperature around the motor is 40°C.
Is the DHI self-priming?
No. Pentair’s manual states that the DHI is not self-priming, so the pump casing and suction pipe must be filled with water before it starts, and it must never run dry. The most reliable layout is a flooded suction from a tank at or above pump level. If the pump sits above the water, fit a valve on the suction line to hold the prime; see our guides on how to prime a pump and suction lift and NPSH.
Should I choose a DHI 2 or a DHI 4?
Up to 60 l/min, a DHI 2 gives more head for less power: the 2-60 gives 37 metres at 40 l/min from a 0.6 kW motor. Above 60 l/min you need a DHI 4, which runs to 120 l/min; the 4-50 still gives 30 metres at 100 l/min.
What protection do the 400v T models need?
The three-phase motors must be wired through a suitable isolator with fuses and a thermal overload relay set to the motor’s actual running current, as Pentair’s manual requires. The full-load current at 400v is between 1.4 and 2.0 A depending on the model.
What size are the connections?
Every DHI model has a 1¼” threaded suction port and a 1¼” threaded delivery port, set at 90 degrees to each other.
For help choosing a DHI model or putting together a booster set around one, call the AES Rewinds team on 01252 515169 or email sales@aesrewinds.com. You can also browse all booster pumps and surface mounted pumps.
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