Model is sdh or pdh – Reznor SHH (Indoor PreevA) Unit Installation Manual User Manual
Page 17
Form I-PDH/SDH/PEH/SHH/PXH, Page 17
FIGURE 10 -
High Altitude
(>6000ft/
1830M)
Pressure
Switch
Requirement
Pressure
Switch
NOTE: If elevation is above 6000 ft
(1830M) and the following conditions apply,
installation of a high altitude pressure
switch is required. When a replacement
switch is needed, contact your distributor
for the switch and follow the instructions
below to install the high altitude pressure
switch before starting the heater.
PDH or SDH Size installed
above 6000 ft (1830M)
Switch
P/N
Label
Color
Setting
75, 100
197031
Purple
0.35” w.c.
125
197032
Pink
0.45” w.c.
150
197029
Lt Blue
0.60” w.c.
175, 200, 225, 250, 300, 350, 400A
201160
Brown
1.05” w.c.
Derate by Valve Outlet
Pressure Adjustment
if needed for High
Altitude Operation
Instructions for High Altitude Derate - Models PDH, SDH, and SHH
1. Refer to TABLE 10, and determine the required valve outlet pressure(s) for the
elevation where the heater will be operating. If unsure of the elevation, contact the
local gas supplier. If unsure of the type of gas control, check the option list on the
unit wiring diagram.
If the elevation on the rating plate does not match the elevation of the installation site,
follow these instructions to adjust the valve.
TABLE 10 - Valve Outlet
Pressure Settings by
Elevation for Models
PDH, SDH, and SHH
(Does NOT apply to
Option AG58 or D12G --
see NOTE on page 16.)
Instructions for changing pressure switch:
1. If the unit is installed, turn off the gas and the power.
2. In the control compartment, locate the pressure
switch that needs to be replaced. (
NOTE: If there are
two pressure switches, the high speed switch to be
replaced is toward the top of the unit.)
3. Mark and disconnect the two wires attached to the
pressure switch.
4. Mark and disconnect the sensing tube(s) from the
pressure switch.
5. Locate the two screws holding the switch mounting
bracket. Remove the pressure switch. Save the
screws.
6. Using the same screws, install the high altitude
pressure switch. Attach the sensing tube(s) and wires.
7. If the unit is installed, turn on the power and the gas.
□
Model is SDH or PDH
□
Elevation on the rating plate is not above 6000 ft (1830M)
□
Unit has a single or two-stage gas control (Option AG1,
AG2, AG3, AG15, AG16, AG60, AG61, DG1, DG5, or
D12C).
NOTE: If equipped with a two-stage control with
a two-speed venter (Options AG8, AG9, AG9H, AG60,
AG61, DG1, DG5, and D12C), there are two pressure
switches. Only the high speed pressure switch needs to be
changed.
2. Locate the 1/8” outlet pressure tap on the valve (FIGURE 6). Turn the knob or
switch on the top of the valve to “OFF”. Connect a manometer to the 1/8” outlet
pressure tap in the valve. Use a water column manometer that is readable to the
nearest tenth of an inch. When making the adjustment, turn the adjustment screw
IN (clockwise) to increase pressure or OUT (counterclockwise) to decrease.
Outlet Pressure Settings (inches w.c.) by Altitude for Installation in the UNITED STATES
Altitude
Full Rate Outlet
Pressure (Single-
Stage & 2-Stage
High Fire) - Applies
to Options AG1,
AG2, AG3, AG15,
AG16, AG60, AG61,
AG62, DG1, DG5,
D12C, D12F
Full Rate Outlet Pressure with
Electronic Modulation - Applies to
Options AG8, AG9, AG9H, AG40, DG2,
DG6, and D12B (measured at the outlet
pressure tap just behind the orifice
adapter when there is a minimum
of a 20VDC signal at the electronic
modulating valve)
NOTE: Options do not apply to SHH.
2-Stage Low-Fire
Outlet Pressure -
Applies to Options
AG2, AG3, AG15,
and AG16
2-Stage Low-Fire
Outlet Pressure
with Venter
Motor Controller
- Applies to
Options AG60,
AG61, AG62, DG1,
DG5, D12C
Factory-Set
Bypass Pressure
with Electronic
Modulation
- Applies to
Options AG40,
DG2, DG6, D12B
FEET
METERS
Natural
Gas
Propane
Natural
Gas
Propane
Natural
Gas
Propane Natural
Gas
Propane Natural
Gas
Propane
0 - 2000
0 - 610
3.5
10.0
3.5
10.0
1.8
5.0
0.40
1.8
0.25
1.8
2001 - 3000
611 - 915
3.1
8.8
3.1
8.8
1.6
4.4
0.35
1.5
0.25
1.8
3001 - 4000
916 - 1220
3.0
8.5
3.0
8.5
1.5
4.2
0.34
1.4
0.25
1.8
4001 - 5000
1221 - 1525
2.8
8.1
2.8
8.1
1.5
4.1
0.32
1.4
0.25
1.8
5001 - 6000
1526 - 1830
2.7
7.7
2.7
7.7
1.4
3.9
0.31
1.3
0.25
1.8
6001 - 7000
1831 - 2135
2.6
7.4
2.6
7.4
1.3
3.7
0.30
1.3
0.25
1.8
7001 - 8000
2136 - 2440
2.5
7.1
2.5
7.1
1.3
3.5
0.28
1.2
0.25
1.8
8001 - 9000
2441 - 2745
2.4
6.7
2.4
6.7
1.2
3.4
0.27
1.1
0.25
1.8
Outlet Pressure Settings (inches w.c.) by Altitude for Installation in CANADA
Altitude
Full Rate Outlet
Pressure (Single-
Stage & 2-Stage
High Fire) - Applies
to Options AG1,
AG2, AG3, AG15,
AG16, AG60, AG61,
AG62, DG1, DG5,
D12C, D12F
Full Rate Outlet Pressure with
Electronic Modulation - Applies to
Options AG8, AG9, AG9H, AG40, DG2,
DG6, and D12B (measured at the outlet
pressure tap just behind the orifice
adapter when there is a minimum
of a 20VDC signal at the electronic
modulating valve)
NOTE: Options do not apply to SHH.
2-Stage Low-Fire
Outlet Pressure -
Applies to Options
AG2, AG3, AG15,
and AG16
2-Stage Low-Fire
Outlet Pressure
with Venter
Motor Controller
- Applies to
Options AG60,
AG61, AG62, DG1,
DG5, D12C
Factory-Set
Bypass Pressure
with Electronic
Modulation
- Applies to
Options AG40,
DG2, DG6, D12B
FEET
METERS
Natural
Gas
Propane
Natural
Gas
Propane
Natural
Gas
Propane Natural
Gas
Propane Natural
Gas
Propane
0 - 2000
0 - 610
3.5
10.0
3.5
10.0
1.8
5.0
0.4
1.8
0.25
1.8
2001 - 4500
611 - 1373
2.8
8.1
2.8
8.1
1.5
4.1
0.3
1.4
0.25
1.8