50027910-001 Differential Pressure Switch INSTALLATION INSTRUCTIONS APPLICATION SPECIFICATIONS The Honeywell differential pressure switch senses changes in duct air pressure to confirm air movement, providing a safeguard that airflow is present during the operation of installed IAQ equipment, including the TrueSTEAM Humidification System. SPST: normally open, snap-acting contacts Pressure setpoint contacts: change at 0.04 in. W.C. Electrical 5 amp resistive @ 24VAC One common (C), One Normally Open (NO) quick-connect terminals Operating Temperature: -40F to 190F (-40C to 88C) Pressure Sample Taps Black positive pressure tap. 1/4 in. outside diameter Grey negative pressure tap. 1/4 in. outside diameter Use with 1/4 in. inside diameter tubing (10 ft provided) 4-13/64 (107) 3-13/16 (97) 5/64 (2) 2-1/64 (51) 1-19/32 (41) FULL R Ø3/16 (5) 3/16 (5) M27300 3-15/16 (100) Ø3-1/4 (83) [2] 1/2 (13) Fig. 1. Pressure switch. Table 1. Parts Included. C 1 Item Quantity 2 Rubber Grommet 1 2 2 3 3 2 Tubing Fitting Elbow NEGATIVE PRESSURE PORT 27/32 (21) POSITIVE PRESSURE PORT COMMON (C) TERMINAL 1/4 (6) X 1/32 (1) THICK QUICK CONNECT 3 2 NO M27302 ASSEMBLED IN MEXICO [2] 1/4 (6) NC + PI NORMALLY OPEN (NO) TERMINAL 1/4 (6) X 1/32 (1) THICK QUICK CONNECT M27301 Fig. 2. Pressure switch dimensions. M27323 Tubing, 1/4 in. ID 10 ft Differential Pressure Switch (Fig. 1) 1 Screws, #8 x 3/4 in. sheet metal 2 Terminal Adaptor 2 Mounting position: mount vertically (upright) with Honeywell logo right-side up. Approvals Underwriters Laboratories Inc. Approved: MP2168 Canadian Underwriter Laboratories Inc. Approved: MP2168 69-2205-01 50027910-001 DIFFERENTIAL PRESSURE SWITCH INSTALLATION 3. The return duct is recommended, however the switch can also be mounted to the supply duct. • Read these instructions carefully. Failure to follow them could damage the product or cause a hazardous condition. This control must be installed in accordance with the local code and regulations. • Check ratings and descriptions given in the Specifications section to ensure the product is suitable for your application. • Installer must be a trained, experienced service technician. A IMPORTANT Do not install the switch in an area where temperature exceeds rating of -40F to 190F (-40C to 88C) 1. 2. B Disconnect power from the TrueSTEAM before installing. Mount the switch vertically with pressure connectors facing down, using provided self-tapping screws to secure the switch to the duct. IMPORTANT Calibration accuracy requires that the switch be mounted vertically (as pictured in Fig. 3). SUPPLY DUCT INSTALL - AIR LINE ONLY TO TAP A, CONNECTED TO THE + PORT ON THE AIR FLOW SWITCH RETURN DUCT INSTALL - AIR LINE ONLY TO TAP B, CONNECTED TO THE – PORT ON THE AIR FLOW SWITCH SUPPLY/RETURN DUCT INSTALL - AIR LINE CONNECTED TO BOTH THE + AND – PORTS ON THE AIR FLOW SWITCH M27303 Fig. 4. Mounting the pressure switch. 4. Cut a 3/4-in. diameter hole in the duct within 10 feet of the switch to ensure the provided tubing reaches the pressure tap elbow. 5. Insert the grommet into the duct hole, then insert the tube elbow into the grommet. 6. Connect the tubing to the elbow fitting and the other end to the applicable pressure connection on the switch: a. Black connection if installed on the supply b. Grey connection if installed on the return IMPORTANT With low-speed airflow or variable speed systems it is recommended to run tubing to both the supply and return ducts. M27300 Fig. 3. Pressure switch—oriented vertically. INSIDE OF DUCT 1 1 CONNECT TUBING TO + CONNECTION IF PRESSURE TAP IS MOUNTED TO SUPPLY DUCT. CONNECT TO – IF PRESSURE TAP IS MOUNTED TO RETURN DUCT. M27304 Fig. 5. Install tubing. NOTE: You may cut the tubing to fit the connection length between the elbow fitting and switch. It is also recommended to secure the hose to existing structures to avoid accidental disconnection. 69-2205—01 2 50027910-001 DIFFERENTIAL PRESSURE SWITCH WIRING ELECTRONIC HUMIDISTAT HVAC HUM Fig. 6 shows a close-up of the pressure switch wiring. This applies to all wiring diagrams (Fig. 7–11). R C W Y HUM G 24V 24V 24V ATTACH ADAPTER WIRE TO TrueSTEAM C TERMINAL RECOMMENDED PRESSURE SWITCH 24V HUM HVAC POWER MASTER HUM 1 2 2 3 ASSEMBLED IN MEXICO C 1 COMMON (C) TERMINAL 1/4 (6) X 1/32 (1) THICK QUICK CONNECT C GT R RT 3 GF NORMALLY OPEN (NO) TERMINAL 1/4 (6) X 1/32 (1) THICK QUICK CONNECT 3 2 NO EXT NC + R PI ATTACH WIRE TO HVAC ADAPTOR C TERMINAL Rc W Y G TrueSTEAM - INTERNAL M27398 Fig. 6. Close-up of pressure switch wiring. M27394 THERMOSTAT Fig. 8. Wiring with electronic humidistat. MECHANICAL HUMIDISTAT HVAC HUM HUM R C W Y G 24V RECOMMENDED PRESSURE SWITCH 24V HUM HVAC POWER MASTER HUM C GT R RT GF EXT R Rc W Y G TrueSTEAM - INTERNAL THERMOSTAT M27393 Fig. 7. Wiring with mechanical humidistat. EQUIPMENT INTERFACE MODULE (EIM) D-1 FAN FURNACE BOARD R-2 1 C-3 VISIONPRO IAQ RECOMMENDED PRESSURE SWITCH 24V 24V TrueSTEAM - INTERNAL HUM HUM C GT R CONV. HP 2 W1 O/B 3 W2 AUX C W3 AUX2 R Y Y RC Y2 Y2 RH G G C HEAT 1 RELAY HEAT 2 RELAY HEAT 3 RELAY COOL 1 RELAY COOL 2 RELAY G FAN RELAY H1 U M2 D1 H M2 V1 N T2 RT GF EXT M27395 Fig. 9. Wiring with VisionPRO IAQTM for independent fan control. 3 69-2205—01 50027910-001 DIFFERENTIAL PRESSURE SWITCH EQUIPMENT INTERFACE MODULE (EIM) FAN FURNACE BOARD D-1 R-2 1 C-3 VISIONPRO IAQ 24V HVAC POWER MASTER 24V HUM GT R 2 W1 O/B 3 W2 AUX C W3 AUX2 R Y Y RC Y2 Y2 RH G G C HEAT 1 RELAY HEAT 2 RELAY HEAT 3 RELAY COOL 1 RELAY COOL 2 RELAY G FAN RELAY H1 U M2 HUM C CONV. HP RECOMMENDED PRESSURE SWITCH RT D1 H M2 V1 N T2 GF M27396 EXT TrueSTEAM - INTERNAL Fig. 10. Wiring with VisionPRO IAQTM for operation dependent on HVAC power. 120 VAC 24V HVAC R 24V C R8222 RED RECOMMENDED PRESSURE SWITCH HUM L1 C 120 VAC GT L2 HUM HVAC POWER MASTER R RT GF EXT TrueSTEAM - INTERNAL BLACK AT120 MECHANICAL HUMIDISTAT HUMIDISTAT HUM HUM HUM HUM HAC HAC HAC HAC M27397 Fig. 11. Wiring with a blower fan dedicated to the TrueSTEAM. Automation and Control Solutions Honeywell International Inc. Honeywell Limited-Honeywell Limitée 1985 Douglas Drive North 35 Dynamic Drive Golden Valley, MN 55422 Toronto, Ontario M1V 4Z9 customer.honeywell.com ® U.S. Registered Trademark © 2008 Honeywell International Inc. 69-2205—01 M.S. 04-08