Humidification for Unico Heating Systems

No. 109 / August 2007 Humidification for Unico Heating Systems Unico, Inc. has solicited recommendations from residen- ter feed lines can not be located in the potentially freezing tial size humidifier manufacturers as to their models that ambient. In these cases the safest choice for a humidifier would be compatible with the Unico System recognizing is one that is self-contained and independent of the heat- the factors listed above. These recommendations are ing system. See Table 1 for recommended models. Mois- shown in Tables 1 through 3 for the responding manufac- ture from a centrally located humidifier does a good job turers for the specific applications that are discussed in of migrating to all areas of a structure where rooms are the following paragraphs. kept open enough to communicate with the location of the humidifier. However, locating the self-contained unit im- While Unico, Inc. is passing these recommendations on to mediately below or in the vicinity of the central return air the installers and users, Unico, Inc. assumes no responsi- for the Unico System can enhance the distribution of hu- bility for the selections and recommends that the individ- midified air throughout a building. ual humidifier manufacturers be consulted for their de- tailed installation procedures. It is not intended that this Conditioned Spaces list is complete, as there are some manufacturers that did not respond and some new to the market place that may Where the Unico System is located in conditioned spaces have applicable equipment. There are also two manufac- and where there is no danger of freezing of water lines turer’s models that may be applicable to the Unico Sys- there are additional choices. These are listed in the fol- tem that requires further testing as listed in Table 4. lowing paragraphs from highest to lowest recommended. 1.) Heated Pan or Steam Type Humidifiers. One of Introduction the more viable choices is the heated pan or steam To consider humidification with the Unico Sys- type humidifier that can be mounted in the supply or tem heating system the following factors must be return plenum. See Fig. 1 for detail of placement. In taken into consideration: such cases the plenum should be insulated sheet metal. Because of the small plenum size and high 1.) Higher operating static pressure. typically, 373 Pa pressure of the Unico System, the return location [1.5 inches water column] on the supply side com- would be a better choice. A plenum box can be fabri- pared to conventional systems at 37 to 125 Pa [0.15 cated to match the end of the Unico System coil mod- to 0.50 inches of water]. ule and the humidifier mounted through the side or 2.) Small ductwork system. The plenum (main duct) is Table 1. Self-Contained, Independent of the Heating System either 228 or 178 mm [9 or 7-inch] diameter, or 165 Manufacturer Model Capacity * × 165 mm [6.5 x 6.5-inch] square. Aprilaire Division 350-For Basement Installa- 45 L/day 3.) Reduced airflow. Based on cooling capacity, it may Research Products tion [12 gpd] P.O. Box 1367 be in the range of 32-40 L/s per kW [20-25 cfm per Madison, WI 53701 360-Installed through the 45 L/day 1000 Btuh]. For hot water coils, and especially (800) 334-6011 wall [12 gpd] where cooling capacity may not dictate airflow, the Nortec Industries, Inc airflow may be between 12-48 L/s per kW [8-30 cfm P.O Box 698 N200 @240v (1.64 kW) 48 L/day Ogdensburg, NY 13669 RES Electrode Steam Type [12.8 gpd] per 1000 Btuh], depending on the water temperature. (717)665-9271 4.) Installed in un-conditioned spaces. The Unico Sys- Skuttle Route 10, Box 51 60-BC1, Free standing unit 49 L/day tem is often installed in attics, garages, or crawl- Marietta, OH 45750 with cabinet [13 gpd] spaces, which may be subject to freezing tempera- (800)848-9786 30 L/day tures. ELC 1.1/8A (120v, 1 phase) [8 gpd] 5.) High duct velocity. The supply duct velocity ranges ELC 3.1/14A (120v, 1 49 L/day between 7-13 m/s [1500-2500 fpm]. Walton Laboratories phase) [13 gpd] 90 Dayton Ave. ELC 2.1/4A (208-230v, 1 30 L/day Passaic, NJ 07055 phase) [8 gpd] Unconditioned Spaces (973)815-1001 ELC 2.1/8A (208-230v, 1 60 L/day Free-standing Humidifiers. For systems located in un- phase) [16 gpd] conditioned spaces, such as attics, unheated garages or Electrovap Compact Models basements, the humidification systems which require wa- *Capacity is the maximum rating in gallons per day (gpd) © Copyright 2007 Unico, Inc. Technote 109 — Page 2 on the bottom of this box that should be insulated. Table 3. Power Humidifiers When mounting through the side, keep the humidifier as low as possible so obstruction of the airflow is Manufacturer Model Capacity * Aprilaire Division 68 L/day @49°C minimized and permit the air to flow across the top of P.O Box 1367 760A** [18 gpd @120°F] the humidifier-evaporating pan. Madison, WI 53701 Air Temp (800)334-6011 Honeywell Inc. 68 L/day @49°C Table 2. Steam Humidifiers – Duct Mounted 1985 Douglas Drive North HE 360** [18 gpd @120°F] Golden Valley, MN 55422 Air Temp Manufacturer Model Capacity * (800)345-6770, ext. 7204 Honeywell, Inc 49 L/day HE 420 1985 Douglas Drive North [13 gpd] Trion, Inc 72 L/day @49°C Golden Valley, MN 55422 64 L/day 101 McNeill Rd HE 460 G-100 [19 gpd @120°F] (800)345-6770, ext.7204 [17 gpd] Sanford, NC 27331 Air Temp 49 L/day (800)227-3917 60-1 Skuttle [13 gpd] Route 10, Box 51 64 L/day *Capacity is the maximum rating in gallons per day (gpd) 60-2 Marietta, OH 45750 [17 gpd] **These models are not recommended for installation on the Unico System supply plenum. (800)848-9786 Use optional flush timer 60 L/day using hot water does very little to boost evaporation S2000** Autoflo, EWC Controls, Inc. [16 gpd] rates contest this. Having this information Unico, Inc. 385 Hwy 33 83 L/day S2020** is recommending that power humidifiers be installed Englishtown, NJ 07726 [22 gpd] on the return side only when there is no other viable (800)446-3110 Have built in flush timers option because of the likelihood of capacity reduc- *Capacity is the maximum rating in gallons per day (gpd) tion. No power humidifier manufacturer had any per- **These models are not recommended for installation on formance data for normal return air temperatures, the Unico System return duct and require a minimum of such as 21°C [70°F] but capacity was estimated at 500 CFM for proper operation. 50% of the rated performance at 49°C [120°F] air To minimize mineral build-up be sure to use a hu- temperature. midifier that has a flush timer that replaces the water in the pan periodically. If not built in, it should be Since the static pressure in the Unico System supply available as an optional accessory (e.g. Skuttle). Be plenum is typically 373 Pa [1.50 I.W.C.] the power sure to follow the manufacturer’s instructions for pe- humidifier must withstand this static pressure to op- riodic cleaning to remove any mineral build-up. See erate properly. The first two power humidifiers listed Table 2 for model listings. in Table 3 are not recommended for installation on the supply plenum of the Unico System; the manufac- 2.) Power Humidifiers. Several manufacturers make a humidifier that mounts on the supply plenum and Table 4. Humidifiers Requiring Testing pulls air into the unit past a wetted pad and dis- charges the moistened air back into the supply air Manufacturer Model Capacity * stream at the same location. These humidifiers de- Walton Laboratories 90 Dayton Ave. 30 L/day WF-HP-226 pend on the heated air to evaporate the moisture so Passaic, NJ 07055 [8 gpd] installation on the return where air is about room (973)815-1001 temperature would significantly degrade perform- Nortec Industries D200 @240v, ance. While some manufacturers have indicated using P.O Box 698 1.64kW 48 L/day Ogdensburg, NY 13669 RES Electrode [12.8 gpd] hot water will increase the evaporation rate, other (717)665-9271 Steam Type manufacturers that indicate their testing shows that *Capacity is the maximum rating in gallons per day (gpd) Plenum Box Heating Cooling Blower (Field Fabricated) Module Module Module (MHxxxxx) (MCxxxxx) (MBxxxxx) Control Return Air Adapter Box (UPC 59 or 60) Q-Band and Q-Clip Return Air Duct Plenum (UPC 4 or 5) Adapter (UPC 61 Power or 62) Humidifier Isolation Pads Q-Band and Q-Clip For 10 foot (3.6 m) Return Duct Secondary Do not exceed 100 inches (2.5 m) Drain Pan (UPC 20 or 24) Platform Return Air Box (UPC 1 or 2) Fig 1. Typical Humidifier placement within the Unico System © Copyright 2007 Unico, Inc. Technote 109 — Page 3 turers have indicated these units should not be oper- mounted in the side or on the bottom of the duct. ated at static pressures over 75-100 Pa [0.30 to .40 Testing is necessary to determine nozzle placement I.W.C.]. The manufacturer of the third power humidi- and length of hose limitations. Nortec has designed fier listed, Trion Model G100, has indicated that their their units (this includes the Model N200 in Table 1) unit will operate satisfactorily at the higher static with a disposable cylinder where mineral deposits are pressure.

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