Scale is the solid matter left after water is heated or evaporated. It forms thick deposits on heat transfer surfaces and prevents the heat from being carried off.
Scale deposits reduce water flow, cut heat transfer and cause high head pressure. The compressor works harder and draws extra current, increasing power costs and causing equipment to fail to product the designed capacity.
The life of the equipment itself is reduced. In fact, excessively high head pressure is a common cause of motor burnout which costs considerable inconvenience and money.
Breakdowns occur during the hottest weather when full capacity is needed.
Customers are annoyed and dissatisfied.
When they can't actually see the scale, on the condenser surfaces, inside the piping and water regulated valves, there's a strong possibility it's there if the head pressure is high (more than 10 pounds above normal), or if the liquid refrigerant line is extra warm. But keep in mind that high head pressure can be caused by mechanical problems, too. These should be checked out before the full blame is placed on scale. Here are just a few of these other causes: pump sucking air, water lines too small, louvers or sprays plugged, tower overloaded, fan trouble, or moist air returning.
How to Test the Scale - If there is any question as to whether the scale remover will dissolve the scale, you can check this by putting a sample of scale into a half glass of water with two or three teaspoonful of the acid. Then stir. If the scale bubbles and breaks up or completely dissolves, go to it! If it doesn't bubble, a sample of the scale can be sent to Nu-Calgon for analysis. We will determine whether it contains sulfate, iron oxide, silica, etc. and advise what can be done to remove it.
Nu-Calgon Scale Remover - "Imperial Grade" - The best and safest dry acid cleaner. Scale remover is a powdered sulfamic acid formulation that contains the best inhibitors available for protecting all metals including galvanizing. A built-in pH color indicator shows how much to use, when to add more and helps tell when the system is clean. A wetting agent and anti-foaming agent are included to help it do a better cleaning job.
Liquid Scale Dissolver - A hydrochloric (muriatic) acid with a low-foaming corrosion inhibitors and a built-in pH color indicator. pH test paper also included.
Liquid Acid Versus Powdered Acid - Some acid users prefer liquid acid for cleaning scaled-up equipment, while some prefer safer dry materials. Both types of materials have certain advantages over each other.
Powdered acids, such as our scale remover, provide the utmost safety in handling to the user. They are nonvolatile and give off no obnoxious or corrosive fumes. Any spillage of the dry acid cleaner is swept up as easily as if it were salt. The dry product is non-irritating to unbroken skin and is easily removed by flushing with water. Since they are less dangerous and easier to use, less supervision is required. Powdered acids are safer for the equipment, and when properly inhibited, will provide excellent protection to steel, copper, brass and aluminum surfaces. Certain formulations like our scale remover are exceptionally safe for galvanizing when no copper corrosion products are present in the system. Powdered acids will not remove old corrosion products as fast as liquid acids, so there is less danger of springing leaks in old corroded systems. Adding too much powdered acid will not cause excessive corrosion rates while adding too much liquid acid can increase the corrosion rate tremendously. Powdered sulfamic acid cleaners are also excellent algaecides.
Liquid acids (such as Nu-Calgon Liquid Scale Dissolver) are somewhat more economical, and strong solutions will dissolve scale and iron oxide deposits faster than powdered acid solution. The liquid goes into solution with no stirring which is a desirable feature, especially in cold weather.
Amount of Acid Required: The amount of acid required to completely clean the system depends upon the amount of scale present. It takes about 2 pounds of powdered acid or 1/3 gallon of liquid acid to react with 1 pound of lime scale. Several doses of acid may be necessary to remove heavy scale deposits. No more than 3 doses of acid should be added to the water together. If scale is heavy, it is better to drain the spent cleaning solution and repeat the cleaning procedure with a fresh charge.
Before cleaning with acid, check the spray nozzles or water distribution holes and clean them out. Drain and flush out the sump. Refill it with fresh water and start the pump again. Shut off the bleed, if there is one. This will cut down on the amount of scale remover you'll need, and prevent waste.
As a starting dosage, add 2 to 3 gallons of liquid acid or 10 pounds of "Imperial" Scale Remover for each 50 gallons of water in the system. If the amount of water in system is not known, the starting dosage can be estimated from the following chart. Even though the acid may have a good anti-foaming ingredient, pour slowly into the system to avoid foaming or pump locking because of the gas released in the cleaning process.
| Capacity of System - Tons of Horsepower | Initial Dosage Liquid Acid | Initial Dosage Nu-Calgon Scale Remover |
| 10 | 2 gals. | 10 lbs. |
| 30 | 5 gals. | 30 lbs. |
| 50 | 10 gals. | 50 lbs. |
| 90 | 15 gals. | 75 lbs. |
The acid solution should be circulated for several hours depending upon the thickness and type of scale. One can usually tell when the equipment is clean by observing the acid solution returning from the condenser. When the returning solution does not contain any bubbles or foam it is a sign that the lime scale has been removed.
The built-in pH color indicator in our "Imperial Grade" Scale Remover and Liquid Scale Dissolver is a very good guide to the proper application of the product. It gives the water a green or light blue color with the acid at the desired strength and causes the water to turn dark blue or purple when the acid is mostly neutralized. This, when the water turns purple, more acid should be added to change the color back to light blue or green. Occasionally, the water indicator does not show up very well in a system where there is a lot of dirt, rust, algae, etc. To double check the cleaning operations and acid strength, pH test paper is provided.
Cleaning Individual
Condensers with an Acid Pump
When cleaning individual condensers or other equipment with the No. 31-TX Acid Pump or other acid circulating pumps, the cleaning solution should contain 1 pound of powdered acid for each gallon of water or 1 gallon of liquid acid for each 5 gallons of water. When using liquid acids never use a solution containing more than 1 gallon of liquid acid for each 5 gallons of water.
The acid solution should be circulated for 1/2 to 3 hours depending upon the thickness and type of scale. The circulating solution should be checked periodically with pH test paper to make sure that it remains at the proper acid strength.
One can usually tell when the equipment is clean by observing the acid solution returning. `When the returning solution does not contain any bubbles or foam and is the same color as the solution in the tank, it is a sign the equipment is clean.
