LAARS Mighty Therm VW-PW (Sizes 175-400) - 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 ........................................................ 3
1.3 Technical Assistance ..................................... 3
SECTION 2.
Installation Instructions
2.1 General Information ....................................... 4
2.2 Field Assembly .............................................. 4
2.3 Site Location .................................................. 5
2.3.1 Installation Information ................................... 5
2.3.2 Outdoor Installation (U.S. only) ...................... 5
2.3.3 Flooring - Typical Installation ......................... 6
2.4 Combustion and Ventilation Air Supply .......... 6
2.4.1 Outdoor Air Supply ........................................ 7
2.4.2 Indoor Air Supply ........................................... 7
2.4.3 Exhaust Fans or Vents .................................. 7
2.5 Venting of Combustion Products ................... 7
2.5.1 General Information ....................................... 7
2.5.2 Replacement of Existing Heater .................... 8
2.6 Water Flow .................................................... 8
2.6.1 Reversible Water Connections ...................... 8
2.6.2 Water Chemistry .......................................... 11
2.6.3 Freeze Protection ........................................ 11
2.6.4 Water Hardness .......................................... 11
2.6.5 Pump Requirements .................................... 14
2.6.6 Pressure Buildup in Water System .............. 14
2.6.7 Pressure Relief Valve .................................. 14
2.6.8 Water Pressure ........................................... 14
2.6.9 Pump Installation ......................................... 14
2.6.10 Storage Tank Installation ............................. 15
2.6.11 Thermal Circulation of Hot Water in
Cold Water Supply Lines ............................. 15
2.7 Gas Supply and Piping ................................ 16
2.7.1 General Instructions ..................................... 16
2.7.2 Special Precautions for Propane Gas .......... 16
2.8 Electrical Wiring ........................................... 16
2.9 Combined Space Heating/Potable
Water Heating Systems ............................... 17
2.9.1 Combined Space Heating ............................ 17
SECTION 3.
Operating Instructions
3.1 Normal Operating Sequence ....................... 17
3.2 Start-Up Procedure ...................................... 17
3.3 Setting the Temperature Controls ................ 20
3.3.1 Remote Water Heater Temperature
Control: ........................................................ 20
3.3.2 Internal Water Heater Temperature
Control: ........................................................ 20
3.4 Adjustment for Minimum Input Rate
(models with modulating gas valve) ............. 21
3.5 Hi-Limit Switch Checkout ............................. 22
3.6 Shut-Down Procedure ................................. 22
SECTION 4.
Maintenance
4.1 General Instructions ..................................... 22
4.2 Replacement of Gas Controls ...................... 22
4.3 Heat Exchanger ........................................... 24
4.3.1 Inspecting the Heat Exchanger .................... 24
4.3.2 Cleaning the Heat Exchanger ...................... 24
SECTION 5.
Troubleshooting
5.1 Gas Pressure Tests ..................................... 24
5.1.1 Checking the Main Line Gas Pressure ........ 24
5.1.2 Checking the Manifold
Regulated Gas Pressure ............................. 25
5.2 Electrical Troubleshooting ........................... 25
5.2.1 Heater Does Not Come On .......................... 25
5.2.2 Testing the Transformer .............................. 26
5.2.3 Testing the Electrical Power Supply ............. 26
5.2.4 Testing the Manual Reset
Hi-Limit Switch ............................................. 26
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 .......................................... 27
5.2.8 Testing the Ignition Control
(for spark ignition) ........................................ 27
5.2.9 Testing the Ignition Control
(for standing pilot) ........................................ 28
5.2.10 Testing the High Voltage Ignition Lead ........ 28
5.2.11 Testing the Safety Shutoff
(for standing pilot) ........................................ 28
5.2.12 Testing the Safety Shutoff
(for automatic pilot) ...................................... 28
5.2.13 Testing the Igniter Electrode ........................ 28
5.2.14 Testing the Pilot Thermocouple
(for standing pilot) ........................................ 29
5.2.15 Testing for Pilot burner
(for spark ignition) ........................................ 29
5.2.16 Testing for Burner Ignition
(for standing pilot) ........................................ 30
5.2.17 Heater Will Not Shut Off .............................. 30
5.2.18 On-Off Main Burner Cycling ......................... 30
5.2.19 Testing the Terminal Strip/External
Controls ....................................................... 30
SECTION 6.
Parts List
6.1 General Information ..................................... 30
6.2 Parts List ..................................................... 30