Frequently Asked Questions

1. What are the advantages of Mercury relays over Solid State Relays in A.C. Resistive heating application?

Mercury Relays have a Longer trouble free life, cost effective, they have a greater immunity to voltage spikes, lower voltage drops and less heat generated by the units then Solid State Relays.

2. What is the difference between Resistive and General Purpose?

Resistive has a Power Factor of one and usually used in A.C. resistive heating.
General Purpose is a UL designation for loads with a Power Factor of 0.7 or higher.

3. What is the average life of a relay?

At full contact ratings, the relays tend to last several million operations. Running at lower voltages and currents can add greatly to the life expectancy.

4. What is a Liquid Level Control?

The most common liquid level control is the sump pump float. Our floats can be used to control the levels of many other fluids too. The sump pump float is designated a normally open or pump down. We also make normally closed or pump up floats to control the addition of liquid to keep and tank from going empty.

5. Where is MDI located?

We are located on US 12 East in Edwardsburg, Michigan about a mile from Lunkers (now since closed down) and not to far from South Bend, Indiana and the Notre Dame Fighting Irish (about 35-40 minutes North East).

For GPS Coordinates: 41.79832, -86.05040

Location on Bing Maps

Location on Google Maps

Our see where we are on on page!

6. Can I order directly from MDI?

Yes you can just call or use one of our online forms and let us know you want to order directly from us. We accept Visa and MasterCard. You may also find that we have a stocking distributor in your area.

7. How should I dispose of my old Mercury Relays and Mercury Floats?

Mercury relays and mercury floats can be returned to MDI at 25028 US 12 East, Edwardsburg, MI 49112. Mark the package FOR DISPOSAL. We will make sure that the mercury is properly recycled. You can also send them to your usual Hazardous Waste handler. We also have a Spill Kit available SP-1149.

8. Where should I send old relay full of Mercury?

Send them at any one of the following locations:

Onyx Superior Special Services, Inc.
1275 Mineral Springs Drive
Port Washington, WI 53074
Phone: (800) 556-5267

Bethlehem Apparatus Co., Inc.
890 Front Street, P.O. Box Y
Hellertown, PA 18055
Phone: (215) 838-7034
Fax: (215) 838-6333

MDI Inc.
25028 US 12 East
Edwardsburg, MI 49112
Phone: (269) 663-8574
Fax: (269) 663-2924

Your local waste Management Authority
Other Permitted Mercury Recycling Centers

9. What is MDI's warranty policy?

Mercury Displacement Industries, Inc. warranty's its products to be free from defects in our materials or workmanship for one year, and will replace any units with such defects. Warranty is void if units are improperly applied. Mercury Displacement Industries, Inc. shall not be liable for special or consequential damages.