Armstrong M/MH Series standard steam jacketed distribution manifolds are designed for use with 9000/1000 series direct steam humidifiers. They are recommended when the vapor absorption distance is not the most critical factor or is less than 36 inches (91 cm). The required size and quantity of manifolds are determined by the face area of the duct or air handling unit, maximum humidification capacity, steam pressure, and the required absorption distance. Armstrong Humid-A-ware humidification sizing software can assist with these calculations.

Installation Guidelines

Armstrong Humidifiers for air handling systems may be installed in fan housings, plenums, or ducts.

Installation Orientation

Normal manifold installation is with the manifold extending horizontally. When required, the manifold may extend vertically upward. It must not extend vertically downward.

Horizontal manifolds should be perfectly level with the discharge holes pointed upstream against the air flow.

Insulation Note

If the manifold is insulated, discharge holes must point downstream to prevent condensation on the metal insulation cover. Manifolds over 1 foot in length should be supported.

Steam supply and condensate drain piping should be made in accordance with good piping practice. Trap discharge must be connected to a return line with pressure well below the supply pressure to the humidifier.

WARNING

Steam humidifiers (or other products) should be installed in locations that allow routine inspection and accessibility for maintenance operations. Armstrong recommends that steam humidifiers not be placed in locations where unusual instances of malfunction of the humidifiers or the systems might cause damage to nonrepairable, unreplaceable, or priceless property.

Primary Methods of Installation

Figure 60-1. Method Number 1 & Figure 60-2. Method Number 2

Figure 60-3. Method Number 3

Manifold Data and Dimensions

Figure 61-1. Steam Distribution Manifold Data

Cross-Section Dimensions

Model No.	“N”	“R”	“S”	“T”	“X”	“Y”	“Z”	Steam Supply
91 and 1100	5-11/16”	2”	1”	1”	1-1/4”	1-7/8”	1-13/16”	1/2” NPT
92 and 1200	8-9/16”	2”	1”	1”	1-3/4”	2-5/8”	2-1/16”	3/4” NPT
93 and 1300	9-1/16”	2”	1-5/8”	1-5/8”	2-1/8”	3-1/8”	—	1-1/4” NPT
94 and 1400	13-1/2”	2”	1-5/8”	1-5/8”	3-1/4”	4-1/4”	—	2” NPT

Manifold Lengths and Duct Widths

Manifold Model No.	M-1	M-1.5	M-2	M-3	M-4	M-5	M-6	M-7	M-8	M-9	M-10	M-11	M-12
L (Length)	12”	18”	24”	36”	48”	60”	72”	84”	96”	108”	120”	132”	144”
W-Duct Width (Min.)	8”	15”	21”	31”	43”	53”	65”	77”	89”	101”	113”	125”	137”
W-Duct Width (Max.)	14”	20”	30”	42”	52”	64”	76”	88”	100”	112”	124”	136”	148”
Shipping Wt. (91/1100)	3 lbs	4 lbs	5 lbs	6 lbs	8 lbs	10 lbs	12 lbs	14 lbs	15 lbs	17 lbs	19 lbs	21 lbs	23 lbs
Shipping Wt. (92/1200)	4 lbs	5 lbs	6 lbs	9 lbs	11 lbs	13 lbs	16 lbs	18 lbs	21 lbs	22 lbs	25 lbs	28 lbs	30 lbs
Shipping Wt. (93/1300)	6 lbs	8 lbs	10 lbs	13 lbs	17 lbs	21 lbs	24 lbs	29 lbs	32 lbs	37 lbs	41 lbs	43 lbs	46 lbs
Shipping Wt. (94/1400)	-	-	-	-	24 lbs	30 lbs	34 lbs	40 lbs	45 lbs	51 lbs	55 lbs	60 lbs	64 lbs

Note: Insulated manifolds are available. Consult factory.

Recommended Number of Manifolds

Duct height at humidifier location	No. of manifolds to be installed for one or more humidifiers
37” to 58”	2
59” to 80”	3
81” to 100”	4
101” & over	5

Note: If you have specific vapor trail considerations, please contact the Armstrong HVAC Application Engineering Department.

Multiple Manifold Pipe Sizes and Adapter Numbers

Humidifier Size	Manifold Pipe Adapter No.	Pipe Connection Size
91	A-4967-B	1/2"
92	A-4967	3/4"
93	A-4967-L	1"*
94	A-5002	2"
1100	A-4967-S	1/2"
1200	A-4967-P	3/4"
1300	A-4967-R	1"*
1400	A-5002-C	2"

*Manifold tube is 1”. Jacket connections are 1-1/4”.