Lochinvar Shield SWR125

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Overview

Function Description
Important Technical Specifications
Usage Features
Maintenance Features

The provided document is an installation and service manual for the Lochinvar SHIELD Commercial Water Heater.

Function Description

The SHIELD Commercial Water Heater is a high-efficiency appliance designed to provide hot water for commercial applications. It utilizes an advanced stainless steel heat exchanger, an electronic control module, and a storage tank to achieve fully condensing operation. The system works by a blower pulling in air and gas through a venturi, mixing them, and pushing them into the burner for combustion. The electronic control module regulates the blower speed to control the water heater's firing rate, while the gas valve senses negative pressure to ensure gas flows only when powered and combustion air is flowing. An internal pump circulates water between the tank and the heat exchanger, mixing incoming water for maximum efficiency.

Important Technical Specifications

Models Covered: SWR125, SWR150, SWR200, SWR285, SWR400, SWA150, SWA200, SWA285, SWA400, and SWA500.
Input Modulation (Btu/hr):
- SWR125(N,L): 25,000 - 125,000
- SWR150(N,L) / SWA150(N,L): 30,000 - 150,000
- SWR200(N,L) / SWA200(N,L): 39,800 - 199,000
- SWR285(N,L) / SWA285(N,L): 57,000 - 285,000
- SWR400(N,L) / SWA400(N,L): 79,800 - 399,000
- SWA500(N,L): 100,000 - 500,000
Water Content (Gallons): Ranges from 65 to 110 gallons depending on the model.
Water Connections: 1-1/2" for all models.
Gas Connections: Ranges from 1/2" to 1" depending on the model.
Vent/Air Size: 3" for 125-200 models, 4" for 285-500 models.
Power Supply: 120 VAC, 60 Hz (15 amp circuit recommended).
Ventilation: Category IV positive pressure venting with flue producing condensate. Approved materials include PVC, CPVC, Polypropylene, ABS, Dryer Vent, Sealed Flexible Duct, Galvanized Steel, and AL29-4C Stainless Steel.
Gas Pressure Requirements:
- Natural Gas: 4-14 inches w.c. (minimum-maximum flowing).
- Propane Gas: 8-14 inches w.c. (minimum-maximum flowing).
Modulation: Capable of modulating firing rate from 20% to 100%.
Temperature Control: Target water temperature settable between 60°F and 180°F.
High Limit Operations: Fixed automatic reset high limit at 200°F, adjustable manual reset high limit up to 210°F.
Safety Features: Air pressure switch (blocked inlet detection), flue gas sensor (overheating protection), burner door temperature switch (285-500 models, over 500°F protection), over-temp switch (285-500 models, over 604°F protection), low water cutoff protection, flame sensor, ignition electrode, temperature and pressure relief valve (set at 150 PSI).

Usage Features

Electronic Control Module: Features a liquid crystal display and 4 buttons for making adjustments and reading status.
Setup Wizard: Guides installers through initial start-up parameters.
Service Mode: Allows qualified technicians to force the unit to run at a particular firing rate for combustion adjustment or troubleshooting.
Night Setback: Programmable feature to reduce the tank setpoint during specific times of the week to save energy.
Building Management System (BMS) Integration: Can be controlled by a BMS (optional Modbus or BACnet control) using a 0-10 VDC signal to control tank setpoint or firing rate.
Error Logging: Stores the last 10 faults with date and time of occurrence.
Dry Contacts: Provides runtime contacts (burner running) and alarm contacts (unit locked out or powered off) for external monitoring.

Maintenance Features

Annual Inspection: Recommended by a qualified service technician, including checking for leaks (water, gas, flue, condensate), verifying vent/air line conditions, checking system water pressure/expansion tank, inspecting control settings, and checking ignition/flame sense electrodes.
Condensate Trap: Requires regular cleaning and filling with fresh water to prevent flue gas emission.
Heat Exchanger Cleaning: Procedures for cleaning the flue side of the heat exchanger using a nylon bristle brush (metal brushes are not recommended).
Anode Rod Inspection: Magnesium anode rods in glass-lined tanks should be periodically removed and inspected for deterioration to provide cathodic protection.
Burner Maintenance: Procedures for removing and cleaning the burner with compressed air.
Temperature Sensor Checks: Ohmmeter readings for inlet, outlet, tank, and flue temperature sensors can be compared to tables in the manual for diagnostic purposes.
Control Module Fuses: Accessible fuses (F2, F3, F4, F5) for various components (24V DC power supply, pumps, blower) can be inspected and replaced.
Gas Valve Adjustment: Specific procedures for adjusting the throttle screw on the gas valve to optimize CO2 levels in flue products.
Ceramic Fiber Handling: Warnings and safety guidelines for handling ceramic fiber materials in the combustion chamber, including wearing NIOSH certified dust respirators and eye/skin protection.