LAARS Mighty Therm LO-NOx PW (Sizes 500-1825) - Install and Operating Manual - Manual (Page 2)

LAARS HEATING SYSTEMS Page 2
TABLE OF CONTENTS
SECTION 1.
General Information
1.1 Introduction ................................................... 3
1.2 Heater Identification ...................................... 3
1.3 General Flow Requirement ........................... 3
SECTION 2.
Installation
2.1 Heater Placement ......................................... 4
2.2 Installation of Indoor Heaters ........................ 4
2.2.1 Combustion Air Supply .................................. 4
2.2.1.a Conventional Ventilation ............................... 4
2.2.1.b Forced-Air Ventilation ................................... 5
2.2.2
Venting .......................................................... 5
2.2.3 Removal of Existing Heater .......................... 6
2.3 Installation of Outdoor Heaters ..................... 6
2.4 Gas Supply and Piping ................................. 6
2.5 Electrical Wiring ............................................ 7
SECTION 3.
Water Piping Instruction
3.1 General Piping Practice ................................ 8
3.2 Heating Boiler (PH Model) ............................ 8
3.2.1 Variable Water Flow System ......................... 8
3.2.2 System Pressure Requirements ................... 8
3.2.3 Hot/Chilled Water Systems ........................... 8
3.2.4 Combined Space Heating/Potable
Water Heating Systems ................................ 9
3.2.5 Piping System Requirements ...................... 10
3.2.6 Filling the System ....................................... 10
3.3 Water Heater (PW Model) .......................... 10
3.3.1 Water Chemistry ......................................... 10
3.3.2 Piping System Requirements ...................... 11
3.3.3 Water Expansion ........................................ 11
3.3.4 Pump Requirements ................................... 11
3.3.5 Water Pressure ........................................... 13
3.3.6 Tank Installation .......................................... 14
3.3.7 Two-Temperature ........................................ 14
SECTION 4.
Operating Instructions
4.1 Controls - General ...................................... 15
4.1.1 Electronic Ignition Control ........................... 15
4.1.2 Hot Surface Igniter ...................................... 15
4.1.3 Combustion Air Pressure Switch ................. 15
4.1.4 Operating Controls ...................................... 15
4.1.5 High Limit Control ....................................... 15
4.1.6 Flow Switch ................................................ 16
4.1.7 Low Water Cut Off ...................................... 16
4.2 Start-Up Requirements ............................... 16
4.3 Normal Operating Sequence ...................... 17
4.4 Hi-Limit Checkout ....................................... 17
4.5 Start-Up Procedure ..................................... 17
4.5.1 Lighting Instructions .................................... 18
4.5.2 To Turn Off Gas to Appliance ...................... 18
4.6 Setting the Temperature Controls ............... 18
4.6.1 Hydronic Boilers .......................................... 18
4.6.2 Water Heaters ............................................ 18
SECTION 5.
Maintenance
5.1 General Instructions .................................... 18
5.2 Combustion Air Blower ............................... 19
5.3 Heat Exchanger .......................................... 19
5.3.1 External Cleaning of Heat Exchanger ......... 19
5.3.2 Internal Cleaning of Heat Exchanger .......... 20
5.4 Gas and Electric Controls ........................... 20
5.5 Burner Removal and Cleaning .................... 20
SECTION 6.
Troubleshooting
6.1 Sequence of Operation ............................... 20
6.2 Electrical Components ................................ 21
6.2.1 General Troubleshooting ............................ 21
6.2.2 Electrical Troubleshooting ........................... 21
6.3 Mechanical Components ............................ 23
6.3.1 Pressure Relief Valves Leaking
Intermittently or Steadily .............................. 23
6.3.2 Heater is Pounding, Knocking or
Emitting Steam from Relief Valves .............. 23
6.3.3 Soot in Flueways or in Tubes, or Noxious
Fumes Indicative of Bad Combustion ......... 23
6.3.4 Water Dripping in Firebox ........................... 23
SECTION 7.
Parts Descriptions and
Order Numbers
7.1 Jack and Combustion Chamber
Components ............................................... 25
7.2 Water System ............................................. 25
7.3 Electrical Components ................................ 26
7.4 Gas Train .................................................... 26
7.5 Burner Tray ................................................. 26
7.6 Outdoor Jacket ........................................... 33