Brute FT Series - Page 40

Page 40
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www.Laars.com
Document 4387
The FT Series, Heating Only, Gas Conversion Kit
pg 3 of 4
Table B DIP Switch Settings
MBH 100 140 199
These 3 bottom switches must be set per unit SIZE.
9.
Per Table B, set DIP Switch
5 to OFF
for LP Propane.
10.
Turn ON the GAS and WATER supply to the FT.
11.
Turn ON the FT.
12.
Connect a manometer to the manifold pressure port. For dual port manometers, use the positive pressure
side. Check for proper manifold gas pressure. Refer to Table C.
ON OFF
MIN Fire Normal Operation
MAX Fire Normal Operation
NG Natural LP Propane
3” Vent Size
2” Vent Size
Figure D
Gas Valve for 100 & 140 MBH
Gas Valve for
199 MBH
The gas valve on
the smaller models is
mounted vertically.
Manifold Pressure Port
Manifold Pressure Port
Table C
Manifold pressure Propane Gas (LP) Natural Gas (NG)
MFTHW 100
-0.075 ˝ WC -0.070 ˝ WC
-0.003 ˝ WC -0.000 ˝ WC
MFTHW 140
-0.130 ˝ WC -0.100 ˝ WC
-0.004 ˝ WC -0.002 ˝ WC
MFTHW 175
-0.169 ˝ WC -0.129 ˝ WC
-0.015 ˝ WC -0.015 ˝ WC
MFTHW 199
-0.169 ˝ WC -0.129 ˝ WC
-0.015 ˝ WC -0.015 ˝ WC
CO
2
value
Propane Gas (LP) Natural Gas (NG)
2˝ VENT 3˝ VENT 2˝ VENT 3˝ VENT
MFTHW 80/100
120/140/175/199
9.5~11% 8.5~10.5%
9~10.5 % 8~10%
Refer to the below table.
Manifold pressure Propane Gas (LP) Natural Gas (NG)
MFTHW 100
-0.075 ˝ WC -0.070 ˝ WC
-0.003 ˝ WC -0.000 ˝ WC
MFTHW 140
-0.130 ˝ WC -0.100 ˝ WC
-0.004 ˝ WC -0.002 ˝ WC
MFTHW 175
-0.169 ˝ WC -0.129 ˝ WC
-0.015 ˝ WC -0.015 ˝ WC
MFTHW 199
-0.169 ˝ WC -0.129 ˝ WC
-0.015 ˝ WC -0.015 ˝ WC
CO
2
value
Propane Gas (LP) Natural Gas (NG)
2˝ VENT 3˝ VENT 2˝ VENT 3˝ VENT
MFTHW 80/100
120/140/175/199
9.5~11% 8.5~10.5%
9~10.5 % 8~10%
Refer to the below table.
13.
Establish a call for heat. You may need to disconnect the outdoor reset if you are making this gas
conversion during warm weather.
Shown is a
Model 140
with 3"
Venting and using
Natural Gas
NOTE: Values are in the range of -.001 to -.35 Inches WC are indicative
of proper set-up. If your readings are outside this range, please call
technical support.
4.13 Natural Gas to Propane Conversion (continued)