Tankless with recirculator pump

sparky741 · May 11, 2022

Hello all! I just had a Bosch tankless water heater put in about a month ago and I am enjoying the endless hot water as well as the savings on my electric bill now that the old tanked electric heater is gone. What I am not enjoying is the time it takes for water in the shower and at the faucets to warm up. From what I have read, that may be typical for a tankless heater. I have done some home work and I would like to put a recirculator pump in, but I’m seeking an answer from somebody a little more knowledgeable than myself. I’m an electrical and computer guru, and I have dabbled with some plumbing, but I am certainly no expert. My house has a pex home run setup and what my question is is which way would be the best way to go? Put in the pump along with a bridge valve at every fixture I’d like the water to be warm or just have the pump keep the water in the manifold hot by putting a bridge valve right next to it? I understand the disadvantage to the home run setup is that if I put a bridge valve at the farthest fixture, that is the only one to reap the advantage of the recirculator. If I keep the water in the manifold hot, I would think it would certainly cut down on the time for the water at the fixtures to warm up as well as cut back on how much water goes down the drain. As far as controls, there is a clever fellow on YouTube who put in a “dumb” pump, about $65 or so, and turns it on and off with a smart plug. It can be scheduled on my phone as well as turned on by voice command. “Alexa, turn on the pump for 2 minutes” or something of that nature. Viola! Hot water ready before I get up to the bathroom to shower. Is this plausible?

sparky741 · May 20, 2022

Anybody?

Twowaxhack · May 20, 2022

It should take the same amount of time to get hot water from your tankless as it did your old tank type.

What temp do you have it set at ?

lonaman · May 21, 2022

I want to preface this question with the statement that I am a complete novice and may be completely wrong... Wouldn't adding a recirculator pump negate the purpose of a tankless system?

Twowaxhack · May 21, 2022

lonaman said:
I want to preface this question with the statement that I am a complete novice and may be completely wrong... Wouldn't adding a recirculator pump negate the purpose of a tankless system?

It depends on your purpose.

lonaman · May 21, 2022

Thanks for clarifying.

sparky741 · May 27, 2022

I have it set at 125. It definitely seems as though it takes longer for the water at the kitchen and bathroom sinks to start warming up. Showers may or may not be a little bit longer than before. My thinking is if the water in the manifold is circulated and warmed up, it would cut back on the amount of water going down the drain until it’s warm at the fixture. I’m looking at using a “dumb” pump with a flow switch in conjunction with a smart plug, so everything will be on a schedule as well as voice control with Alexa.