Lochinvar Power-Fin Designer's Manual page 9

Designer's Guide / Power-fin Water Heater
The four basic Vent Categories are determined by two characterisitics, Condensation and
Pressure.
CONDENSING VERSUS NON-CONDENSING
The possibility for condensation to form in a stack is based on the temperature of the flue
products. If the temperature of the flue products remains consistantly above dewpoint,
condensation will not form. If the temperature drops below dewpoint, condensation will form.
So how does condensation apply to the Power-fin? Easy. The Power-fin's firing rate determines
the stack temperature. Depending upon the model, the Power-fin may operate at a high firing
rate producing a high stack temperature to stay above dewpoint or it may modulate down to a low
firing rate producing a low stack temperature that allows the flue gas temperature to drop below
dewpoint. This is explained further in Part 2, "Firing Code".
POSITIVE VERSUS NON-POSITIVE
Positive or non-positive pressure in the vent is determined by the capacity of the appliance's
blower AND the diameter of the vent in order to PUSH the flue products. If the same appliance is
connected to a larger diameter stack, the blower CANNOT PUSH the flue products. The positive
pressure goes negative, or non-positive.
So how does pressure apply to the Power-fin? Again, easy. Depending upon the model, the
Power-fin will be factory trimmed for a small vent connection to positive vent or a large vent
connection to non-positive vent. This is explained further in Part 2, "Firing Code".
Part 2
Firing Codes
The model number for all Lochinvar products has a "Firing Code".
Example: PFN0752PM-M9
"PFN0752PM" is the basic model number / "-M9" is the Firing Code.
This collection of letters and numbers has a specific meaning. The Firing Code is important
because it specifies a particular feature set that is factory trimmed to match the planned venting
system. With the correct firing code, Lochinvar will factory trim your water heater to fire at correct
input rate and provide the correct vent connection to meet your needs.
There are THREE basic firing codes. Here's how they work.
F9 models / Power-fin 0502-1302 only
"F9" means "Full Fire" or 100% Full Fire with no modulation. (No Turndown)
Temperature – Firing at 100% of input rate, the Power-fin 0502-1302-F9 models will always
produce a high stack temperature. Non-Condensing.
Pressure – The Power-fin 0502-1302-F9 models are factory trimmed with a large diameter vent
connection. The blower CANNOT PUSH the flue products through a similarly sized stack
therefore creating a non-positive pressure. Non-Positive Pressure.
F9 models are Category I.
B9 models / Power-fin 1501-2001 only
"B9" means "Bi-level Fire" or 50% to 100% firing rate. (2:1 Turndown)
Temperature – Even firing at the lowest input rate of 50%, the Power-fin 1501-2001-B9 models
will produce a high stack temperature. Non-Condensing.
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LOCHINVAR CORPORATION
300 MADDOX SIMPSON PKWY
LEBANON, TN 37090
www.lochinvar.com