Installation, operation and maintenance instructions document 2137a h0250000a installation, operation and maintenance instructions for mighty therm tm lo-nox volume water heater model vw-pw sizes 250/400 for natural gas only u.S. Reg. 1,483,289 canada reg. 333,796 for your safety: this product must ...
Laars heating systems page 2 table of contents section 1. General information 1.1 introduction .................................................... 3 1.2 warranty ........................................................ 4 section 2. Installation instructions 2.1 general information ....................
Mighty therm lo-nox volume water heater page 3 v vent cap drafthood w 10 1/4 26 16 1/2 41.9 10 25.4 8 20.3 5 1/4 13.3 3 1/2 9 gas connection far side 14 3/4* 37.5 38* 96.5 front view side view 30 1/2* 77.5 pump h laars lo-nox mighty therm mighty therm section 1. General information 1.1 introduction ...
Laars heating systems page 4 for outdoor installations. In special circumstances an outdoor vent cap may be required. Check the part number on the rating plate. The vw, pw heaters are design certified for indoor installation when equipped with a special drafthood, which must be installed without mod...
Mighty therm lo-nox volume water heater page 5 figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Figure 10. Figure 11. Figure 13. Figure 14. Figure 15. Drafthood switch receptacle. Figure 12. Out of production.
Laars heating systems page 6 2.3.2 outdoor installation caution outdoor installations are not recommended in areas where the danger of snow blockage exists. A. Locate the heater in an open, unroofed area. Do not locate the heater below or adjacent to any doors, windows, louvers, grills, etc., which ...
Mighty therm lo-nox volume water heater page 7 table 2. Air openings to outside. Required net free opening area directly from outside at top at bottom model in. 2 cm 2 in. 2 cm 2 250 63 406 63 406 400 100 645 100 645 note: for screens or louvers, add 50%. Figure 20. Indoor installation and venting. ...
Laars heating systems page 8 note: do not use sheet metal screws at the snap lock joints of type b double-wall gas vents. Do not weld or bolt the vent pipe to the heater drafthood. The weight of the stack must not rest on the heater. The drafthood and heater top must be easily removable for normal h...
Mighty therm lo-nox volume water heater page 9 blocked, it is possible, especially for fan-assisted devices, to vent backwards through non-operating appliances sharing the vent, allowing combustion products to infiltrate occupied spaces. If the appliances are allowed to operate in this condition, se...
Laars heating systems page 10 mettre l’appareil inspecté en marche. Suivre les instructions d’allumage. Régler le thermostat de façon que l’appareil fonctionne de façon continue. 5. Test for spillage at the draft hood relief opening after 5 minutes of main burner operation. Use the flame of a match ...
Mighty therm lo-nox volume water heater page 11 heat flow pressure* water temp exch. Water rate drop rise model passes category gpm l/s ft. M ° f ° c 250 2 soft 22 1.4 5.8 1.8 18 10 normal 34 2.1 11.2 3.4 12 7 hard 46 2.9 19.1 5.8 9 5 400 2 soft 34 2.1 13.3 4.1 19 11 normal 34 2.1 13.3 4.1 19 11 har...
Laars heating systems page 12 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 figure 24. Hot water supp...
Mighty therm lo-nox volume water heater page 13 2.6.4). If tappings are smaller than the recommended pipe size, a larger pump may be required. Consult the factory if in doubt. 7. Install a pipe in the tank drain fitting that goes to a floor sink, and install a drain valve. If a floor sink is not ava...
Laars heating systems page 14 6. Install a non-restrictive manual gas shutoff valve for service and safety. Check the local codes. 7. Disconnect the heater and its individual shutoff valve from the supply gas system during pressure testing of the system at pressures higher than 1/2 pounds per square...
Mighty therm lo-nox volume water heater page 15 4. Connect all field-installed devices (draft switches, relays, timers, outdoor temperature reset devices, etc.) to the heater wiring at points labeled field interlock. Section 3. Operating instructions note: safe lighting and other performance criteri...
Laars heating systems page 16 warning: if you do not follow these instructions exactly, a fire or explosion may result, causing property damage, personal injury or loss of life. • if you cannot reach your gas supplier, call the fire department. C. Use only your hand to push in or turn the gas contro...
Mighty therm lo-nox volume water heater page 17 avertissement: quiconque ne respecte pas à la lettre les instructions dans la présente notice risque de déclencher un incendie ou une explosion entraînant des dommages, des blessures ou la mort. • appelez immédiatement votre fournisseur de gaz depuis u...
Laars heating systems page 18 figure 29. Mighty therm lo-nox, pw250. Out of production.
Mighty therm lo-nox volume water heater page 19 figure 30. Mighty therm lo-nox, vw250. Out of production.
Laars heating systems page 20 figure 31. Mighty therm lo-nox, pw/ph 400. Out of production.
Mighty therm lo-nox volume water heater page 21 figure 32. Mighty therm lo-nox, vw/hh 400. Out of production.
Laars heating systems page 22 plug figure 34. Scale inspection. Figure 33. Flame patterns. If the unit is equipped with an automatic reset high limit, set the automatic reset high limit 20°f (11°c) above the outlet temperature to avoid nuisance lockouts. Set the manual reset high limit 5°f (3°c) abo...
Mighty therm lo-nox volume water heater page 23 7. Tighten the header bolts progressively, starting with the two center bolts. Maximum torque is 20 inch pounds (27 nm). Do not over-torque. 8. Pressure test the heat exchanger for leaks with city water supply before re-installing. 9. When placing the ...
Laars heating systems page 24 5.2 electrical troubleshooting warning electricity can cause property damage, injury, or loss of life. All troubleshooting and servicing must be done by a qualified hot water heater technician. This section describes procedures for checking the electrical power and cont...
Mighty therm lo-nox volume water heater page 25 2. Voltage outside of the required range may be due to poor wiring connections, to other loads (e.G., air conditioners, compressors) on the circuit, to high pump load, or to an electrical utility company problem. 5.2.4 testing the manual reset hi-limit...
Laars heating systems page 26 1. Touch the other lead of the voltmeter to both terminals of the manual reset hi-limit switch. The voltmeter should read 20 to 28vac at both terminals. 2. If no voltage is detected at one terminal, reset the manual reset hi-limit switch by pressing the reset button. Ch...
Mighty therm lo-nox volume water heater page 27 5.2.10 heater will not shut off 1. If the heater stays on with the brown wire on the gas valve disconnected, replace the gas valve. Warning never attempt to repair the gas valve. Such attempts will void the warranty, and could lead to dangerous results...
Laars heating systems page 28 key model order no. Description no. Part no. 43 gasket cast iron flange ...................................... All s0076500 bronze flange ......................................... All s0028000 bronze flange ......................................... All s0053100 44 nut ....
Mighty therm lo-nox volume water heater page 29 34 33 30 32 31 26 27 28 23 24 25 29 c see next page for details 64 66 18 b a 62 65 63 54 51 a 3 1 2 b 20 21 61 17 14 burner tray (see next page for details) 4 50 22 c 53 52 46 43 52 51 38 50 43 46 42 52 37 5 out of production.
Laars heating systems page 30 39 58 57 40 40 44 36 38 41 45 44 45 35 12 16 13 7 10 9 59 59 55 37 41 15 8 6 11 56 out of production.
Mighty therm lo-nox volume water heater page 31 out of production.
H0250000a waterpik technologies 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 905.844.2635 www.Laars.Com litho in u.S.A....
