Installation, operation and maintenance instructions document 2051c h0147500c installation, operation and maintenance instructions for mighty therm volume water heaters model vw-pw sizes 175-400 for your safety: this product must be installed and serviced by a professional service technician, qualif...
Laars heating systems page 2 table of contents section 1. General information 1a. Introduction .................................................... 3 1b. Warranty ........................................................ 3 1c. Technical assistance ..................................... 3 section 2. In...
Mighty therm vw - pw volume water heaters page 3 a 8-1/2 in. (216mm) inlet outlet top view c c optional vent cap for outdoor use drafthood drafthood must be installed in the field header location outlet 40-9/16 in. (1030mm) inlet 5-1/2 in. (140mm) 26-1/2 in. (673mm) side view v 30-3/16 in. (767mm) b...
Laars heating systems page 4 hot hot number for the drafthood is on the heater rating plate. Follow this procedure to make the conversion: a. Remove the top filler plate, stamped “hot”, by slipping a fine-blade screwdriver into the slot at the rear of the plate and gently prying it up (see figure 2)...
Mighty therm vw - pw volume water heaters page 5 d. Disengage the flue transition ring from the stack extension and place it on top of the collector assembly as shown in figure 4. E. Slide the adapter plate over the bottom of the stack extension as shown in figure 5. Fit the stack extension down ove...
Laars heating systems page 6 figure 11. Standard base for combustible floor. Figure 13. Typical roof mounting with standard combustible mount base. Figure 12. Typical roof mounting. Figure 10. Outdoor location installation. Figure 9. Incorrect outdoor installation. Window or grill indoor room 4 ft. ...
Mighty therm vw - pw volume water heaters page 7 2d-1. Outdoor air supply when combustion air comes directly through an outside wall, each opening must have a minimum free area of at least one square inch for each 4,000 btu/h input of the total input rating of all appliances in the enclosed area. (i...
Laars heating systems page 8 warning in cold weather, uninsulated outside vents can chill the rising flue products, blocking the natural draft action of the venting system. This can create a health hazard by spilling flue products into the heater room. Avoid oversize vent piping or extremely long ru...
Mighty therm vw - pw volume water heaters page 9 rear tile cover flow switch conduit gap closure grommet drain valve metal channel (for capillary tube) terminal strip heat exchanger assembly gap closure drain plug drain valve rear tile cover hex head screws manual reset high limit switch box figure ...
Laars heating systems page 10 15. Remove the flow switch conduit retaining clip and the elbow leading into the jacket. 16. Reach inside the control compartment and release the retaining nut in the upper right corner. The nut should only be finger-tight. 17. When the conduit is pulled away from the j...
Mighty therm vw - pw volume water heaters page 11 2f-4. Water hardness consider the water hardness when selecting a pump for the heater (see table 3). Hard water needs a pump which can provide high flow to prevent scaling, while soft water needs low flow to prevent erosion. 34. Carefully slip a hand...
Laars heating systems page 12 heat flow pressure* water temp exch. Water rate drop rise model passes category gpm l/s ft. M ° f ° c 175 2 soft 22 1.4 5.8 1.8 13 7 normal 34 2.1 11.2 3.4 8 4 hard 46 2.9 19.1 5.8 6 3 4 soft 11 0.7 4.9 1.5 25 14 normal 17 1.1 9.3 2.8 16 9 hard 23 1.5 15.9 4.8 12 7 250 ...
Mighty therm vw - pw volume water heaters page 13 hot water return from building throttling valve check valve bldg. Loop circ. Pump hot water to building cold water optional cold water supply when adequate tank opening not available to drain heater service valve pump to drain conventional tank figur...
Laars heating systems page 14 protection device, excessive heat may trip the thermal switch. This could cause the pump to shut down intermittently, resulting in rapid scaling of the heat exchanger. 4. If designed for floor mounting, install pump securely on concrete block or pad at least 6 inches (1...
Mighty therm vw - pw volume water heaters page 15 2f-11. Thermal circulation of hot water in cold water supply lines under certain circumstances, thermal circulation will occur in the cold water pipe supplying the water to the heating system. This happens in a multi-story building when the cold wate...
Laars heating systems page 16 damage to the heater's gas controls. The minimum pressures specified is for gas input adjustment. 10. The correct burner manifold gas pressure is stamped on the rating plate. The regulator on the gas valve is preset at the factory, and does not normally need adjustment....
Mighty therm vw - pw volume water heaters page 17 section 3. Operating instructions 3a. Normal operating sequence note: safe lighting and other performance criteria were met with the gas manifold and control assembly installed on the heater during tests specified in ansi z21.13. Warnings vent pipes,...
Laars heating systems page 18 figure 26. Typical example of wiring schematic, system 1. Ignition system no. 1 - standing pilot on/off or mechanical modulation volume water heaters (325-400) version b natural or propane gas pump included on pw models, field supplied on vw models.
Mighty therm vw - pw volume water heaters page 19 figure 27. Typical example of wiring schematic, system 12. Ignition system no. 12 - electronic ignition on/off or mechanical modulation volume water heaters (325-400) version b natural or propane gas pump included on pw models, field supplied on vw m...
Laars heating systems page 20 3e. Hi-limit switch checkout after running the heater for a long enough period, bring the water temperature within the range of the hi-limit switch and slowly back off the high limit setting until the heater shuts off. The main burners should reignite when the hi-limit ...
Mighty therm vw - pw volume water heaters page 21 electronic pilot standing pilot figure 29. Flame patterns. 4b. Replacement of gas controls the gas and electric controls installed on the heaters are designed for both dependable operation and long life. Safe operation of the heater depends on their ...
Laars heating systems page 22 6. Remove the two screws that fastens the anti- rotation bracket on the left side of the gas valve (see figure 30). 7. Remove the pilot gas tube and copper thermocouple shield, if present, from the gas valve. Caution label all wires prior to disconnection. Wiring errors...
Mighty therm vw - pw volume water heaters page 23 4c-2. Cleaning the heat exchanger an inspection and cleaning of the complete heat exchanger can only be done by removing it from the heater. 1. To remove the heat exchanger, refer to section 2f-1. Caution black carbon soot buildup on a dirty heat exc...
Laars heating systems page 24 4. Remove the 1/8 inch (3.2 mm) national taper pipe (npt) test plug in the shutoff valve and replace it with the 1/8 inch (3.2 mm) npt fitting from the manometer kit. 5. Attach one end of the manometer hose to the fitting on the gas valve and the other end to the manome...
Mighty therm vw - pw volume water heaters page 25 3. Make sure the gas valve is on and there is gas pressure in the line. 4. Check all electrical connections and wiring. Finding a loose connection or a charred wire can save a lot of time and money. 5. Check the fuse inside the black, twist-lock fuse...
Laars heating systems page 26 5. Check for leaks of the flue collector, vent pipe, gaskets, and all connections. 6. Check the flue pipe for blockage. 5b-7. Testing the fuse to test the fuse: 1. Clip a lead of the voltmeter to the grounding terminal. 2. Touch the other voltmeter lead to the 24vac ter...
Mighty therm vw - pw volume water heaters page 27 2. Touch the other voltmeter lead to the red 24v terminal on the ignition control. 3. If the voltmeter reads voltage, the temperature control and the manual reset hi-limit switch are not keeping the heater from firing. 4. Make sure the pilot burner i...
Laars heating systems page 28 5b-11. Testing the safety shutoff (for standing pilot) after lighting the heater, test the ignition system safety shutoff. 1. With the main burners firing, turn the gas valve control knob off. 2. Turn power to the heater off. 3. Set the temperature control to its lowest...
Mighty therm vw - pw volume water heaters page 29 thermocouple thermocouple adapter gas valve millivolt meter pilot figure 41. Testing the pilot thermocouple. 5b-17. Heater will not shut off 1. If the heater stays on with the brown wire on the gas valve disconnected, replace the gas valve (see secti...
Laars heating systems page 30 section 6. Parts list for vw and pw heaters 6a. General information to order or purchase parts for the laars vw-pw volume water heaters, contact your nearest laars wholesaler. If they cannot supply you with what you need, contact customer service, laars (see back cover ...
Mighty therm vw - pw volume water heaters page 31 item description part number 60. Tee bronze .................................................... P0075600 cast iron ................................................. P0071700 61. Bushing, brass ....................................... P0018500 62. Bra...
Laars heating systems page 32 h0147500c waterpik technologies, inc. 6000 condor drive, moorpark, ca 93021 • 805.529.2000 • fax 805.529.5934 20 industrial way, rochester, nh 03867 • 603.335.6300 • fax 603.335.3355 480 s. Service road west, oakville, ontario, canada l6k 2h4 • 905.844.8233 • fax 905.84...
