Manual Recirculation Mode Rheem Tankless

[TWHI]

Greetings everyone, thanks for being here for the conversations.

We have a Rheem 9.9gpm ECOH180DVRHLN Tankless water heater with built-in recirculation pump and cross over at the farthest location (EcoNet is not installed.) We have programed the recirculation pump for a schedule but it is not satisfying our erratic pattern of use. The learning mode is not making sense either as it has not been able to adapt.

We are looking for a way to manually start the internal recirculation pump with this unit. A little research has shown that there is a method for adding a push button to start a pump, but it is only for external recirculation.
for reference (https://images.homedepot-static.com/catalog/pdfImages/43/433a47e1-7304-4cf7-9e2d-bdc206ee0858.pdf)

Is there a way we can add the ability of manual recirculation (button) to start the internal recirculation? Might you have another suggestion besides turning off internal recirculation and adding external pump at farthest location? Enabling the eternal recirculation in this unit is not an option as we don't have ability to add the appropriate return loop to this old home.

Thank you in advance.

Service Manual for this model (https://s3.amazonaws.com/WebPartners/ProductDocuments/7496DB1F-380B-46AC-951E-BA17CA39DF8A.pdf)

 

[Bannerman]

The link you provided for the Hot button activation kit, is shown as intended to activate the internal pump.

Because you are using the home's cold water piping as a hybrid return line back to the WH, the temperature sensor supplied with the kit, will likely need to be located not on the return line at the WH, but at the far side of your home where the crossover connection will be feeding hot water into the cold water piping. Locating the temperature sensor there will stop the circulation pump when hot water arrives at that location, which will prevent the cold water piping from becoming filled with hot water.

You didn't specify how the home plumbing is connected to the WH. Because the crossover valve is causing the cold water piping to act as the circulation return line, the connection to the water heater will not use the Recirculation Return mode configuration shown on page 11 of the manual, but must utilize the bYPS configuration shown on page 12.