Here are some letters that were sent in by our readers.

Response To Wheeler's Refrigerant Column

Mr. Wheeler missed a good AHR Expo. Many new products were introduced, like NU-22, the subject of his column in the February Supply House Times (page 46), and it would have afforded him a research opportunity to report on these products for his readership.

Mr. Wheeler alludes to a "secret" that makes NU-22 miscible with standard refrigeration oil and then is concerned that the specification sheet comparison between NU-22 and R-22 "has been deliberately made difficult to understand."

The information he refers to is a product brochure with simple properties comparison at one temperature. Apparently if it were a full-blown engineering report on solubilities, densities and viscosities of refrigerant/lubricant mixtures and thermodynamic properties of saturated and superheated refrigerants, he would be satisfied. There are no secrets. Call us and we can discuss fully any application.

He loosely discusses hydrocarbons, flammability, oil and fractionation. The comments are so random that it is not clear as to the point. So let's talk about all of them in some order.

1. Flammability: NU-22 (R-417A) has an A1 safety classification from ASHRAE standard 34 (A = nontoxic 1 = nonflammable), the same classification as R12, 22, 134a, 409A, 414B, etc.

2. Many refrigerant products use hydrocarbons, R-402A &B (HP80 &81) R-414B (Hot Shot), R-417A (NU-22). But this is only hydrocarbons. There are many other refrigerants that have a flammable (3) or mildly flammable (2) classification, such as R-32 (A2) used in R-410A.

3. Hydrocarbons allow for favorable oil return in many situations, but miscibility is only part of the equation. Proper refrigerant velocity and solubility are all contributing factors.

4. Fractionation, or the separation of a liquid mixture into parts by the preferential evaporation of the more volatile component, only occurs when liquid and vapor are present together and there is an extremely slow vapor leak. Practically speaking, should a leak occur in a system, blend leaks out. The volatility of the expulsion of gas lifts the blend. The liquid line is pure blend so the condenser coil and evaporator coil have the two-phase refrigerant. In storage (?) unless there is a leak the blend stays intact.

5. It is not necessary to replace the complete charge if a leak occurs with a blend. Pump down the refrigerant, cool the refrigerant to ambient temperature, check your liquid pressure/ temperature relationship. If it's more than 5-7% off, you may have a problem. But think where your leak is. (See No. 4 above.)

Although we compete against the DuPont, Honeywell, Atofina in many areas, we at ICOR believe in education, not marketing hyperbole, and were distressed to read the comments on R-410A, specifically concerning the "hot service truck." Since the refrigerant cylinders and the recovery cylinders are D.O.T. regulated for the higher pressures, Mr. Wheeler's comments are inflammatory.

While the comments made in the last paragraph are complimentary and appreciated, the bulk of the article is cavalier in presentation and leaves one with more questions than substantive information.

Jim Terry

Product Engineer

ICOR International Inc.

Indianapolis, Ind.

Don't Disregard Hydronic Electric Baseboard Heating

Although without question Dan Holohan is well-versed in the subject of hydronics, there is a flaw in his objectivity. He refuses to acknowledge the value and desirability in some applications for hydronic electric baseboard heating units which are currently in use in tens of thousands of residences and commercial applications in the United States.

They provide clean, safe, quiet, uniform heat like the old boiler-based cast-iron radiator, but require no furnace, plumbing, pipes or ducts, have no moving parts to maintain, and provide the economy of separate room temperature control. The liquid (water or silicone) is hermetically sealed at the factory. Users report 20-30% savings over a centrally powered system. A tissue placed in permanent contact with the heating element will not ignite.

We sent data to Mr. Holohan and he provided a polite reply stating "I still prefer systems that are boiler based. I think they offer more flexibility when it comes to domestic water production, snow-melting, zoning, outdoor-reset control and overall economy."

This response belies the issue, since he ignores the most obvious application of heating the air in a room environment.

It no longer makes sense to generate heat at one location and transfer it via liquid or air to various points with subsequent transmission loss. In our opinion "Central Heat Is Obsolete."

There is obviously a place for this product in the marketplace. We trust that some of your readers will agree.

W.L. Morrison

President

Advanced Environmental Systems

Winston-Salem, N.C.

February Issue Was Fun To Read

I just wanted to tell you that the February issue of Supply House Times was really good. It had a practical article about dealing with disasters, a funny one about curious (stupid) people, one reviewing new refrigerants, an editorial with a hopeful tone, etc. It was fun reading. Thanks.

Ben Sweazy

Branch Manager

Utility Equipment Co.

Omaha, Neb.