Water Heater TRD Thermal Release Device 101

Where is the TRD located?

The TRD is located inside the combustion chamber of the water heater, beneath the burner assembly.

Are TRDs expensive?

If TRD replacement is not covered under warranty (see following point), they typically cost anywhere from about $30.00 each to $200.00 (or more) depending on the vendor and type of TRD.

Is TRD replacement covered by warranty?, What are common causes of TRD failure?

TRD replacement is a grey area because warranty coverage of this part depends on a case-by-case basis, determined by the cause of the TRD’s break. The most common cause of TRD replacement our customers encounter is improper venting which is considered an installation issue, which would not be covered by warranty. In this case or for other instances of flammable vapor detection, Rheem recommends replacement of the unit. If there are no venting/installation issues nor other type of flammable vapor incident, the TRD may have been unintentionally triggered as the result of a manufacturing issue with your unit. Hence, Rheem also utilizes TRDs to ensure the quality of their products. As a result, each water heater is only permitted three TRDs during its lifetime: the original one that was installed in the factory and two replacements (if needed). Multiple TRD failures can be a sign of an internal manufacturing issue or an undetected venting issue. In these cases, Rheem is able to track TRD replacement based on their warranty service case log and technical support calls for each serial number; if there is a suspected manufacturing defect, technical support will likely send a contracted service provider to assess the water heater and report the findings prior to making a final determination. 

Are TRDs interchangeable?

No. According to Rheem’s replacement kit instructions, service professionals should: “Verify Replacement Combustion Shutoff Device Assembly part number matches the part number of the assembly removed. This part is unique to the water heater model; there is NOT a universal TRD. Contact technical services to verify correct part number.” There are different types of TRDs for different units, depending on the gallon capacity of your unit. Each type of TRD produced tends to have four variations, whose individual and kit part numbers vary by a single digit, which coordinates with a difference in temperature tolerance. Since all TRDs have black liquid in their bulbs and different temperature tolerance levels, Rheem has two methods identifying which temperature tolerance is permitted: the part number which is engraved into the TRD’s bracket and a stripe of paint on the top of the TRD. Installing an incorrect TRD can result in a safety hazard. Additionally, installing a TRD with a higher temperature tolerance may result in the unit over heating and creating a fire hazard. 

There is NOT a universal TRD.

Can I replace the TRD myself?

Per Rheem’s installation instructions and U.S. Water Heating recommendations, you should not attempt to change your unit’s TRD on your own and should instead have service performed by a qualified service provider. This is because replacing the TRD requires turning off the gas and electric supply to the unit, then removing the burner access door (a.k.a. the burner access door and the entire burner assembly). The burner access door must also be properly re-installed for safety purposes, then assessed for gas leaks.