Hydra-Oil

Role and importance of oil used in Wanner Hydra-Cell Pro^® pumps

We get a lot of questions about Hydra-Oil, the oil that ships in every new Wanner Hydra-Cell Pro^® pump. This article covers the grades Wanner^® supplies, what to put in after the first fill, and how to change it.

Hydra-Oil comes as conventional, synthetic blend and fully synthetic. Inside the pump it does three jobs:

1. Lubricate sliding and rotating parts
2. Carry heat off those parts
3. Form the hydraulic pistons that move the diaphragms and make flow

Oil thickens when it is cold and thins when it is hot. The grades used in Hydra-Cell Pro pumps are picked so those three jobs still work with:

• The room or outdoor air around the pump
• Pump-head material
• How hard and how long the pump runs
• Special fluid or contamination rules

Nomenclature

Most oils are labeled with numbers on either side of a “W”:

The number before the “W” is resistance to flow at 0°F. The number after the “W” is resistance to thinning at 212°F.

You want the oil thin enough that the shaft can start, thick enough in service to keep a film on the moving parts, and still in the viscosity band a hydraulic piston needs to respond quickly.

Environmental Considerations

Outdoors, or indoors with no temperature control, ambient air can push you to a different grade. 5W-30 for cold rooms. 15W-50 for hot rooms.

Pump Head Materials

The “head” is the manifold and valve plate. Non-alloy and brass heads shed heat better, so 10W-30 is typical. Ductile iron, stainless and other alloys hold more heat, so 10W-40 may be used because it stays thicker at the higher oil temperature.

EPDM diaphragms need oil that is listed as EPDM-compatible. Standard mineral oil attacks EPDM.

Operational Characteristics

Shaft speed and hours on the clock drive oil temperature. A pump near its maximum RPM on continuous duty wants a grade that does not thin out — 10W-40 or 15W-50 even on a non-alloy head. Process-fluid temperature does not add much to oil temperature, though it may be why you oversized the pump and run it slower.

Special Considerations

The diaphragm is the barrier between process liquid and oil. It usually fails from over-pressure or from chemistry/temperature the elastomer cannot take. Some plants cannot accept even a trace of oil in the product, so they specify a special fill. Food-contact oil is the usual request in food, beverage and bio-pharm. We also supply water-soluble oil and ammonia-resistant oil when the site or the emission rules require it. Use the standard Hydra-Oil viscosities as the selection guide for those specialties.

Hydra-Oil Part Numbers

Seven part numbers cover the line: A01-114-3430, A01-114-3440, A01-114-3415, A01-114-3416, A01-114-3410, A01-114-3407 and A01-114-3402. The chart below maps oil to pump model and shows how much each model holds.

When to Use Hydra-Oil

Hydra-Oil has extra molybdenum for the first 100 hours on a new pump. After that you can run a commercial 5W-30, 10W-30, 10W-40 or 15W-50, and it will usually cost less. Large pumps or a lot of pumps may still want the 2½-gallon Hydra-Oil pack. Stay with Hydra-Oil for food-contact and EPDM-compatible fills.

Why Change the Oil

Metal fines stay suspended and add friction and heat. Heat and friction then cut lubricity, so wear speeds up if you never change the oil. The hydraulic end will last decades on a sane change schedule. Those parts can be replaced; they cost more time and money than a fluid-end kit.

Oil Change Frequency

The IOM for your model has the interval. A typical chart looks like this:

Oil Changing Procedure

Shut the pump down. Open the drain and let most of the oil and sediment out. Close the drain and refill. If there is a sight bottle, fill to about the bottom quarter of the cylinder. If not, fill to just below the entrance to the expansion chamber. That chamber sits on top of the pump under the fill cap. Oil grows as it heats; the chamber gives it room so it does not leak out.

Oil Level Monitoring

If oil in the product is a problem, watch the level. The cheapest way is a sight bottle. If you cannot see oil in the bottle, it has left the hydraulic end — torn diaphragm, shaft-seal leak, or a cracked housing.

A float switch on the bottle will close a circuit if the level rises or falls too far.

Remote skids often use a monitoring kit with a Murphy SWITCHGAGE^®. Same idea as a bottle and float, mounted off the pump and built for the field.

Oil Cooling Systems

A Hydra-Cell Pro running continuously typically sits at 185–190°F oil. Very hot rooms, or hot process liquid, can push oil past 200°F. The cooling kits will take 250°F oil down to 185°F with ambient air at or below 110°F, or with 3 GPM of water at or below 80°F. Air-cooled or water-cooled depends on the site. Oil is pumped through fins the same way a car radiator works.

Change the oil on schedule and the hydraulic end will stay in the pump for years.

Related Articles

• Troubleshooting Hydra-Cell Pro pumps
• Horsepower for high-temperature liquids
• Analyzing diaphragm damage
• Hydra-Cell Pro design overview
• Car-wash D10, H25 and D35 oil intervals