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noeljb t1_jdjah1g wrote

Recirculating pump and you have a tankless water heater? .. .. .. Yea, NO.

You don't have hot water to recirculate. If you recirculate enough water to turn the heater on then you are heating water 24 hours a day in pipes that are not even insulated.

Smaller point use heaters are your only real option. I guess you could put small (tanked) water heater in bath and kitchen, but that kinda defeats the hole thing.

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lollroller t1_jdjhus8 wrote

I can’t believe this wasn’t said sooner. A recirculating pump makes NO sense whatsoever with a tankless heater.

EDIT: I should have looked into this before that comment. It looks that a recirculating pump and water return circuit can be used to return hot water into either an insulated storage tank, small tank water heater, or even another tankless; which in turn feeds the warm/re-heated water in series back into the hot water supply.

This would reduce the time needed to get newly heated water from the primary tankless to the fixtures, not a bad idea

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Nearby_Maize_913 t1_jdk1jus wrote

I was sort of thinking the same thing. Though a recirculating pump isn't all the efficient on a tank, but probbably way more efficient than tankless

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noeljb t1_jdkr7cx wrote

But wouldn't you just be running the heating elements constantly?

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lollroller t1_jdkv75i wrote

The examples I saw the tankless would only be heating water when a faucet was running

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noeljb t1_jdkwwsy wrote

So how does that get you instant hot water at the far bath?

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lollroller t1_jdn11bw wrote

By locating the storage tank just ahead of the far bath.

Any time anybody runs hot water in the house, the recirculating loop warms up and fill the storage tank with hot water

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GrimResistance t1_jdlytr2 wrote

Some tankless water heaters have built in recirc pumps or have an option for an external pump. You do need insulated piping though.

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