Janus P15 Axial Piston Pump

Inlet Conditions

The pumps are available in 2 designs; either 2 port un-boosted or 3 port boosted configuration.

2 Port Design

Predominantly used in power pack applications where the supply water is fed to the pump from a low pressure source i.e. local tank or water mains with very low supply pressure. This design of pump can not lift water and the inlet pressure must be positive at all times. The pipe-work must be sized to ensure that even under minimum head conditions, the water pressure is still positive at the inlet. Failure to ensure this can result in premature pump failure. A simple check is to remove the pump inlet hose and measure the flow. The inlet flow rate must be 20% over the maximum delivery flow when the tank is at it’s lowest level. This ensures the inlet has positive pressures under dynamic conditions.

Unboosted

Do not place a filter between the tank and pump unless a pressure switch protecting against negative pressure is fitted. Filter all water upon entry to the tank. All supply pipe work to be a maximum diameter and minimum length.

The ports are clearly marked P (pressure) and T (tank) do not reverse or turn the shaft in the wrong direction or failure will result.

3 Port Design

When water is fed to the pump at a minimum of 2.5 bar by either a very high pressure water main, a head or column of water in excess of 25m in height or by an external boost pump, then the 3 port design unit should be incorporated. It separates the inlet water of the pump from the internal leakage water which must be piped away to a low pressure sump or drain if possible. Low casing   pressure will prolong the shaft seals life and prevent low pressure cavitation issues. The minimum case pressure and maximum inlet pressure is desired, a minimum positive inlet pressure of 2.0 bar above T pressure is required at all times.

Boosted

Boosted pumps can rotate in either direction. Inlet and outlet ports change according to shaft rotation. Maximum casing pressure 2.5 bar.

 

Motor Pump Assemblies

We offer a standard range of bell housings and couplings that connect pumps directly to the B5 electric motor flange. For detailed options and combinations, refer to our **Pick-A-Pack datasheet**. To ensure reliable operation, avoid inducing axial or radial loads on the pump’s output shaft. Whenever possible, use a three-part gear-style coupling. If the drive shaft and spigot location maintain concentricity within 0.05 mm, you may use direct inline drive assemblies.

 

Temperature

These units deliver full performance between **2°C and 50°C**. When operating below freezing, request our **Monopropylene Glycol datasheet** for an environmentally friendly antifreeze solution. Although operation above 50°C is possible, it will reduce the unit’s volumetric efficiency. In such cases, consult TWHC and specify the maximum operating temperature for guidance.

 

Filters

Always pre-filter incoming water to a **nominal rating of 10 µm (25 µm absolute)** with a filter element rated at **β10 = 75 or better**. For closed-loop systems, return line filtration is highly recommended. You may also consider high-pressure filtration; however, since these filters are manufactured from stainless steel, they represent a more costly option.

 

Fluid

Use drinking water that complies with **EEC Directive 98/83/EC** as the standard. If you are uncertain about water quality, consult TWHC. Our standard product also operates effectively on technical water such as distilled, RO, or demineralised water. Depending on your environment, we may need to adjust seal materials or construction.

Additionally, the pumps can run on non-flammable fluids like **Glycol 95/5 mixtures**, provided internal clearances are modified accordingly. Always specify the exact operating fluid in all enquiries and orders. While the standard construction can handle seawater, its higher corrosion potential may require a more noble material for long-term durability.