29
Installation Manual
VISCOSITY:
The HTF Viscosity over the service temperature range is based on a specific gravity
15/15°C (60/60°F) 1.;053-1.063. DOWFROST inhibited glycol-based fluid has an effective operating
temperature range of -50°F to 250°F, while DOWFROST HD inhibited glycol-based fluid is effective
from -50°F to 325°F. At temperatures below -50°F, increased viscosity (>1,000 centipoise) can make
use of these fluids impractical unless larger pumps are installed. At the upper end of the operating
range for DOWFROST fluid, a maximum bulk temperature of 250°F is recommended. Film tempera-
tures should not exceed 300°F. In the case of DOWFROST HD fluid, a maximum bulk temperature of
325°F is recommended, with film temperatures not to exceed 375°F. DOWFROST and DOWFROST
HD fluids can tolerate brief temperature excursions up to 100°F above the maximum recommended
temperatures. However, extended exposure of the fluids to to temperatures in excess of 50°F above
the maximum recommended temperatures will result in accelerated degradation of the glycol and
inhibitor systems. In addition, the film temperature should remain within 50°F of the bulk fluid tem-
perature and the pressure at all points in the system should be at least 5 psi greater than the vapor
pressure exerted by the fluid to avoid localized boiling and resulting precipitation. At temperatures
above 150°F, the system must be closed to avoid rapid oxidation of the propylene glycol, inhibitor
depletion, and subsequent increased corrosion. Automatic make-up water systems should be avoid-
ed in order to prevent undetected dilution or loss of glycol and consequent loss of freeze and cor-
rosion protection.
FLAMMABILITY:
When mixed with water, neither DOWFROST nor DOWFROST HD fluids are
flammable because they have no measurable flash point (Pensky-Martens Closed Cup) in concen-
trations up to 80% glycol. Undliluted DOWFROST and DOWFROST HD have a flash point of 214°F
(Pensky-Martens Closed Cup). It is possible to ignite solutions of propylene if enough water has been
vaporized and the concentration of propylene glycol increases to greater than 80 percent.
INSPECTION AND TREATMENT OF HEAT TRANSFER FLUID:
You can quickly deter-
mine the condition of your fluid by examining its appearance and odor. Any drastic variation from
the initial fluid specifications, such as a black or dark-grey color, presence of an oily layer, burnt odor,
or any heavy sludge in the fluid may indicate the need for fluid replacement.
TESTING YOU FLUID’S pH LEVEL:
Control of pH between 8 and 10 is important to minimize
corrosion and glycol degradation. Using narrow range pH paper such as pHydrion Control paper
with a 7.2 to 8.8 pH range is an easy and reliable way to read your pH level. A pH tester can also
measure alkalinity or acidity and give you an indication of the reserve alkalinity or inhibitor level of
the fluid. The desirable pH range should fall between 8.0 and 10.0. Adjustments can be made using
a 50% solution of sodium hydroxide or potassium hydroxide if the pH is approaching the acidic
range (below 8.0). An inexpensive pH tester is available from Misco Products. The accuracy of this
product is +/- 0.5 pH. Contact Misco Products at 1-800-358-1100 and ask for the Dow discount.
SPILL, LEAK AND DISPOSAL PROCEDURES FOR DOWFROST:
Using appropriate safe-
ty equipment, small spills may be soaked up with common absorbent material. For large spills, the
fluid should be pumped into suitable containers located in diked areas. Residual material should be
cleaned up with water. Concentrate can be handled according to local, state, and federal regulations.
PART 5: TROUBLESHOOTING
(CONT’D)
