INDOOR VENTING—General Requirements
The vent pipe must be the same size or larger. The MiniMax NT Standard heaters are capable of a 360-degree discharge rotation and operate with a positive vent static pressure and with a vent gas temperature less than 400° F. The total length of the horizontal run must not exceed the length that is listed below in the tables.
Please note the allowable vent runs for each stack pipe diameter are different and can not be exceeded.
Note that each 90-degree elbow reduces the maximum horizontal vent run by 8 feet and each 45-degree elbow in the vent run reduces the maximum vent run by 4 feet. See the tables below for the maximum vent lengths using a 90-degree and 45-degree elbows. The MiniMax NT Standard induced-draft pool and spa heater uses positive pressure to push flue gases through the vent pipe to the outside. This requires a completely sealed vent system—single wall vent pipe with sealed-seams and joints may be used. Flue gases under positive pressure may escape into the dwelling with any cracks or loose joints in the vent pipe, or improper vent installation. The vent pipe must be of a sealed-seam construction such as those listed for use with category III appliances. Alternately, single wall or double-wall type B duct which has had duct seams and joints permanently sealed using cements or other suitable means which are rated for use at the flue gas temperatures of 325° F. and are permanent are acceptable. The use of listed thimbles, roof jacks and/or side vent terminals are required; and the proper clearances to combustible materials must be maintained in accordance with type of vent pipe employed— in the absence of a clearance recommendation by the vent pipe manufacturer, the requirements of the Uniform Mechanical Code should be met. The ventilation air requirements for the MiniMax NT Standard heater and can be found on page 15. It is recommended that vent runs over 18 feet be insulated to reduce condensation related problems and/or the use of a condensate trap in the vent run close to the heater may be necessary in certain installations such as cold climates. The MiniMax NT Standard is suitable for through-the-wall venting.
Recommended sources for Side-wall vent hood terminals include: The Field Controls Co. (2308 Airport Road, Kingston, NC 28501, (800)742-8368) and Tjernlund Products Inc. (1601 Ninth Street, White Bear Lake, MN 55110, (800) 255-4208)—consult manufacturer for model information and availability.
CAUTION
Do NOT combine exhaust vent pipes to a common exhaust vent in multiple unit installations. Run separate vent pipes.
45 ft. Maximum Vent Run, 5 in. O.D. vent (Equiv. ft.)
| Additional 90° elbows | Additional 45° elbows |
| after first elbow | after first elbow |
| | | |
Quantity | Reduced Max. | Quantity | Reduced Max. |
| | | |
1 (2 total) | 37 | (2 total) | 41 |
| | | | |
2 | (3 total) | 29 | (3 total) | 37 |
| | | | |
3 | (4 total) | 21 | (4 total) | 33 |
| | | | |
22 ft. Maximum Vent Run, 4 in. O.D. vent (Equiv. ft.)
| Additional 90° elbows | Additional 45° elbows |
| after first elbow | after first elbow | |
| | | |
Quantity | Reduced Max. | Quantity | Reduced Max. |
| | | | |
1 (2 total) | 14 ft. | (2 total) | 18 | ft. |
| | | | | |
2 | (3 total) | — | (3 total) | 14 | ft. |
| | | | |
3 | (4 total) | — | (4 total) | — |
| | | | | |
