Lochinvar Power-Fin Designer's Manual page 17

Designer's Guide / Power-fin Water Heater
Final note about Category IV
Retrofit of an original design Power-fin installed with Concentric Kit
If your job is a retrofit of a Power-fin 0250-1000 built to the original design, here's a little tip. If the
PFN0250PM-F9, PFN0500PM-F9, PFN0750PM-F9 or PFN1000PM-F9 is installed with a
concentric vent kit, it is installed as a Category IV appliance. The "F9" firing code on the original
Power-fin is not 100% equal to the "F9" firing code on the new Power-Fin. An original Power-fin
installed with concentric vent more closely matches the "M9" models. Therefore, when specifying
the new replacement, remember to check the type of vent system currently installed.
Category II Venting
An important detail in the Category IV section is Category IV venting MAY NOT be common
vented. Category IV is positive pressure stack and you cannot combine positive pressure stacks.
This is where switching to Category II can be useful.
We take the standard Power-fin "M9 Firing Code" with its low
Btu/hr input and low stack temperature and we increase the stack
diameter. That changes the stack pressure from positive to non-
positive. Plus the stack will remain a condensing stack because
of the potential for low Btu/hr input and corresponding low stack
temperature. This changes the vent Category from IV to II.
Of the six layouts listed on page 8, three can be installed as
Category II venting. Notice that only vertical termination is
permissible with Category II venting.
Vertical Vent with Air from the Equipment Room
Vertical Vent with Air from the Rooftop
Vertical Vent with Air from the Sidewall
There are three important considerations when specifying Category II venting.
CATEGORY I
CATEGORY III
Non-Condensing
Non-Positive Pressure
F9 or B9 Models
CATEGORY II
CATEGORY IV
Condensing
Condensing
Non-Positive Pressure Positive Pressure
M9 Models
M9 w/ Vent Increaser
The Category II kits are as follows:
MODEL
PFN0502PM-M9
PFN0752PM-M9
PFN1002PM-M9
PFN1302PM-M9
PFN1501PM-M9
PFN1701PM-M9
PFN2001PM-M9
1. The Power-fin MUST be M9 Firing Code. The appliance will
have modulating fire and a Category IV vent connection.
2. A special vent adapter MUST be specified to convert the
appliance from Category IV vent diameters to Category II
vent diameters. The increase in vent diameter is crucial to
change from Category IV positive pressure to Category II
non-positive pressure.
3. The combined vent MUST be properly sized for the
combined appliances.
VENT CONNECTION INCREASER
4" to 7"
5" to 9"
6" to 10"
8" to 12"
6" to 8"
7" to 9"
8" to 10"
17
LOCHINVAR CORPORATION
300 MADDOX SIMPSON PKWY
LEBANON, TN 37090
www.lochinvar.com
Category II
Category II
Category II
KIT NUMBER
KIT3131
KIT3132
KIT3133
KIT3134
KIT3106
KIT3107
KIT3108