LAARS Mighty Therm LO-NOx VW (Sizes 250/400) - Installation, Operation and Maintenance Instructions - Manual (Page 2)

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 ....................................... 4
2.2 Field Assembly .............................................. 4
2.3 Site Location .................................................. 6
2.3.1 Installation Information .................................. 6
2.3.2 Outdoor Installation (U.S. only) ..................... 6
2.3.3 Flooring - Typical Installation ......................... 6
2.4 Combustion and Ventilation Air Supply ......... 7
2.4.1 Outdoor Air Supply ........................................ 8
2.4.2 Indoor Air Supply ........................................... 8
2.4.3 Exhaust Fans or Vents .................................. 8
2.5 Venting (Category I) ...................................... 8
2.5.1 General Information ....................................... 8
2.5.2 Common Venting System .............................. 8
2.5.3 Inspection of Commonly Vented
Appliances ..................................................... 9
2.6 Water Flow .................................................. 10
2.6.1 Water Chemistry .......................................... 10
2.6.2 Water Hardness .......................................... 10
2.6.3 Freeze Protection ........................................ 10
2.6.4 Pump Requirements .................................... 10
2.6.5 Pressure Buildup in Water System .............. 11
2.6.6 Pressure Relief Valve .................................. 13
2.6.7 Water Pressure ........................................... 13
2.6.8 Storage Tank Installation ............................. 13
2.6.9 Thermal Circulation of Hot Water
in Cold Water Supply Lines ......................... 13
2.7 Gas Supply and Piping
(Natural Gas Only) ...................................... 13
2.7.1 General Instructions .................................... 13
2.8 Electrical Wiring ........................................... 14
SECTION 3.
Operating Instructions
3.1 Start-Up Procedure ..................................... 15
3.2. Setting the Temperature Controls ............... 15
3.2.1 Remote Water Heater Temperature
Control ......................................................... 15
3.2.2 Internal Water Heater
Temperature Control ................................... 15
3.3 Hi-Limit Switch Checkout ............................ 22
3.4 Shut-Down Procedure ................................. 22
SECTION 4.
Maintenance
4.1 General Instructions .................................... 22
4.2 Heat Exchanger ........................................... 22
4.2.1 Inspecting the Heat Exchanger ................... 22
4.2.2 Cleaning the Heat Exchanger ..................... 23
SECTION 5.
Troubleshooting and Service
5.1 Gas Pressure Tests ..................................... 23
5.1.1 Checking the Main Line Gas Pressure ........ 23
5.1.2 Checking the Manifold
Regulated Gas Pressure ............................. 24
5.2 Electrical Troubleshooting ........................... 24
5.2.1 Heater Does Not Come On ......................... 24
5.2.2 Testing the Transformer .............................. 25
5.2.3 Testing the Electrical Power Supply ............ 25
5.2.4 Testing the Manual Reset
Hi-Limit Switch ............................................. 25
5.2.5 Testing the Flow Switch ............................... 26
5.2.6 Testing the Fusible Link
(flame roll-out switch) .................................. 26
5.2.7 Testing the Fuse .......................................... 26
5.2.8 Testing the Ignition Control .......................... 26
5.2.9 Combustion Air Blower ................................ 26
5.2.10 Heater Will Not Shut Off .............................. 27
SECTION 6.
Replacement Parts
6.1 Ordering Information ................................... 27
6.2 Parts List ..................................................... 27
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PRODUCTION