Lochinvar Power-Fin, Руководство дизайнера

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LOCHINVAR CORPORATION
300 MADDOX SIMPSON PKWY
LEBANON, TN 37090
www.lochinvar.com
Designer’s Guide / Power-fin Water Heater
Yes, with a specified flow rate, the Power-fin can
give you lime scale free operation. But that is
based on a normal amount of material in the water. Obviously, it is possible to have so much
calcium and TDS in the water that no amount of water flow can wash it away.
Based on the copper-finned tube design, the water chemistry must be in the following range:
Minimum Water Hardness: 5 Grains
Maximum Water Hardness: 25 Grains
Max Total Dissolved Solids: 350 PPM
Acceptable PH: 7.2 to 7.8
If the water is outside these parameters, water softeners or other measures must be taken to put
the water chemistry inside the specified range. Failure of a heat exchanger due to bad water
conditions is a non-warrantable failure.
WATER TEMPERATURE
Water temperature is also an easy concept. The water temperature delivered to the Power-fin
must be high enough to avoid condensation in the heat exchanger. Period.
The minimum return water temperature to the Power-fin water heater is 140°F
(60°C).
Reason why? If the inlet water temperature is less than 140°F, condensate will occur on the
outside of the copper-finned tube and in between the fins. The condensate will collect particles
from the flue products. The moisture and particles build up over time and ultimately will clog the
fins. This leads to improper combustion, sooting, elevated temperatures and premature failure of
the heat exchanger.
Since the water flowing into the water heater comes directly from the storage tank, Lochinvar
recommends maintaining a stored water temperature of 140°F or greater. That works perfectly
for kitchens, laundries and other processes that use high
water temperatures.
In addition, 140°F or greater water temperature will kill the
bacteria that causes Legionella disease, a major concern in
public water distribution systems.
The flip side of that coin is the issue of scald. Direct contact
with 140°F water will cause a scald injury. Water to public
showers and sinks require lower water temperatures. Most
areas of
the country have safety standards for nursing homes,
schools and hotels that require no more than 110°F water
delivered to the customer.
So we are caught between the need to maintain a return
water above 140°F and a system supply temperature below
140°F. What’s a designer to do?
We strongly recommend you store your water temperature at 140°F, then use a mixing valve to
deliver a lower water temperature to the system.
140°
140°