High Altitude & Orifice Chart - Schwank STS-JZ Installation & Owner's Manual

28. HIGH ALTITUDE INSTALLATION
Canada: Heaters can be installed to an altitude of 4500 ft without revision.
To install above 4500 feet refer to recommendation of local authority having jurisdiction.
•
USA: The factory installed orifice is approved for normal altitude up to 2000 ft.
When this appliance is installed above an altitude of 2000 feet in the USA , the input must be
de-rated by 4% for each 1000 ft . Refer to the table next page for orifice sizing and restrictions
that apply to high altitude installation. Check with your local authority regarding de-rating.
NOTE: Installations above 4,500 ft: Restrict the Total Combined System Length as indi-
cated in the TOTAL SYSTEM LENGTH RESTRICTIONS Table below.
MINIMUM VENT LENGTH: (Vented or Unvented [indirect mechanical ventilation])
Minimum vent length of 3 ft (91 cm) is required (NOTE: 200,000 Propane: Minimum 8 ft
•
(244 cm)
MAXIMUM SYSTEM LENGTH (includes:
Each 90° elbow in the system has an equivalent length of 5 ft.
•
A maximum of 2 elbows are allowed in any portion (duct, tube heater, vent) with the ex-
•
ception of up to three 90° elbows in a vertical vent run through the roof
Combustion air duct may be 4" or 5" diameter and is not to exceed lengths in table below
•
• Exceeding the allowable lengths in the table below can create combustion and/or conden-
sation problems and will void CSA Certification and the heater warranty.
• Do not exceed the Maximum Combined System Length regardless of the allowed maxi-
TABLE 8: TOTAL SYSTEM LENGTH RESTRICTIONS:
INSTALLATIONS ABOVE 4500 FEET (Lower altitudes refer to Section 12A)
Do Not Exceed Maxi-
mum Combined
Input
System Length
(Btuh)
4" Air Duct
45,000
& 40 ft
60,000
80,000 50 ft
100,000 40 ft
110,000
to 80 ft
150,000
175,000
& 100 ft
200,000
Tube Heater length + combustion air duct + vent
Max. Air Duct
Length (ft)
(by Duct Diame-
ter)
5" Air Duct 4" Ø
60 ft 20 ft
70 ft 20 ft
60 ft 30 ft
100 ft 30 ft
120 ft 30 ft
Max. Vent
Length (ft)
Individual: 4"Ø
Combined: 6"Ø
length from
each heater
5" Ø
40 ft 20 ft
40 ft 20 ft
50 ft 30 ft
50 ft 40 ft
50 ft 50 ft
55
Example
150,000 Btuh Heater:
Tube Heater Length 40 ft
1 x 90° elbow (vent)
Straight vent
1 x 90° elbow (duct)
Air Duct: 4" Ø
Combined Length
Max. Allowed
Additional 20' for 5" Ø Air Duct
STS-JZ-F / IQ-F I&O Manual Z83.20-2016
RD: APR 2019
):
5 ft
15 ft
5 ft
13 ft
78 ft
80 ft
IM101220
RL: 20C