Technical Service Bulletin : Anode Rods – Solution with Electric Isolation
SOLUTION (REQUIRED ACTION):
ELECTRIC ISOLATION: The following diagram shows a typical GARN installation with no electrical isolation and two separate ground paths: one through the electrical panel, and one through the independent ground rod of the GARN unit. In the following instructions, we will build off of this diagram for explanation and illustration.
There are two options available to accomplish undirected current protection in a GARN unit:
1. FULL ISOLATION (RECOMMENDED) : Electrically isolate the GARN unit from any wired ground path. That means that the GARN tank will not be electrically connected to any wired device that is connected to power or to ground.
------- OR -------
2. SINGLE POINT GROUNDING : Have a single ground point for all wired electrical devices in electrical contact with the GARN unit.
Our recommend solution is full electric isolation (Option 1). But, depending on the installation, full electric isolation may be difficult or impossible to implement, so single point grounding (Option 2) may be the most reasonable approach.
For EXISTING CUSTOMERS:
Assess the anode rods (per the previous technical service bulletins). o If the anode rods DO show signs of the quality issue, remove the rods, and plug the anode rod holes with a 3/4” NPT steel pipe plug using Teflon tape or pipe dope. o If the anode rods DO NOT show signs of the quality issue, then the rods may remain in the unit until the end of their useful life or they can be immediately removed (up to the user). Assess the overall condition of the GARN tank. Remove any rod debris, sludge, and/or sluff build-up on the bottom of the tank. If there is build-up that cannot be easily removed while the tank is filled (in service), now would be a good time to drain the unit, clean it, and refill it with fresh water and chemical. Electrically isolate the tank following the steps outlined in the following sections.
All electrical work must be completed by a licensed electrician in compliance
with all Federal, State, and local codes.
IF ELECTRIC HEATING ELEMENTS ARE INSTALLED:
If electric heating elements are installed, skip to the section UNITS
WITH ELECTRIC HEATING ELEMENTS: on page 6. When electric heating elements are installed, single point grounding must be used, but specific grounding procedures must be followed. LOW VOLTAGE SENSORS: Low voltage sensors do not need isolation accommodations as these sensors are almost universally ground isolated due to their inherent signal sensitivity.
For NEW CUSTOMERS:
Anode rods will no longer be supplied with a GARN unit. Electric isolation is required as part of installation. Follow the steps in the following sections.
Anode Rods – Part 3: Electric Isolation
Rev: 20151130 Page: 2 of 8
© 2015 Dectra Corporation
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