Hot Water Circulating Pump ?

[stillbuilding]

Originally Posted by sailorchic34

Here's a link to a hot water circulator that installs under a sink. It uses the cold water line to return the hot water to the tank, so no extra piping to run. Includes a temperature sensor and a time clock so it only runs when you want and only runs enough to keep the hot water hot. It does not run all the time so saves energy too.

Should work well on a boat too.


Undersink Instant Hot Water Circulating System-ACT-E1 at The Home Depot

Thanks for the advice Sailorchic.
So would you use one of these by-passes at each consumer or would you have a hot water circuit with short sidelines to consumers and just one bypass at the end of the circuit with return to cold water supply to calorifier?
I had envisaged just a simple switched circulating pump but can see your suggested bypass will save power.

[Sailmonkey]

I personally would go the rout of the single pump with a return to the calorifier. All the water you were saving by having hot at the turn of a faucet would be lost by waiting for cold!

[Dreaming Yachtsman]

A momentary contribution to drift on this thread then back on track.

DRIFT: In the last house we owned we had the builder install a return loop from the hot water line at the furthest point from the water heater. The timer controlled pump in that loop ensured hot water for morning showers and all evening. We loved the system but unfortunately the workers insulated the cold and hot water lines together so we had luke warm cold water after the recirc pump ran for a few hours.

BACK ON TOPIC: When outfitting our boat, we installed a valve and return line from the master shower hot water inlet (furthest point from water heater) to a nearby fresh water tank. When we want hot water at the master shower, we open the valve until it warms up then close it and enjoy the shower. This installation assumes a pressurized system. It also provides hot water to all other taps on the boat as they are along the run of pipe from heater to master shower.

As a water saving technique for washing dishes in our double galley sink, we run the hot water into the rinse sink until it turns hot. Then fill the wash sink. Presto, hot water to wash and enough cold water to rinse without wasting a drop.

[bobconnie]

We have always done as Atoll said, use a bucket to save the cold water to use or return to the tanks. simple and easy, and a little old fashion which fits my style LOL Bob and Connie

[sailorchic34]

The little under sink pump would be located at the farthest sink from the water heater/calorifier. If you had two separate runs / circuits on a large vessel / house then you might use two.

Yes, the nice thing about the under sink circ pump is it only runs enough to keep the hot side hot and not all the time. Most set it to run/ cycle on/off in the morning and evening for showers, etc and off during the rest of the day and night. When on, the temperature sensor runs the pump to keep the water warm at the hot side.

Its not perfect, but its a good compromise for places where you can't easily run a return line.

[stillbuilding]

Originally Posted by sailorchic34

The little under sink pump would be located at the farthest sink from the water heater/calorifier. If you had two separate runs / circuits on a large vessel / house then you might use two.

Yes, the nice thing about the under sink circ pump is it only runs enough to keep the hot side hot and not all the time. Most set it to run/ cycle on/off in the morning and evening for showers, etc and off during the rest of the day and night. When on, the temperature sensor runs the pump to keep the water warm at the hot side.

Its not perfect, but its a good compromise for places where you can't easily run a return line.

OK, understand. Good advice thank you.

[atoll]

Originally Posted by sailorchic34

The little under sink pump would be located at the farthest sink from the water heater/calorifier. If you had two separate runs / circuits on a large vessel / house then you might use two.

Yes, the nice thing about the under sink circ pump is it only runs enough to keep the hot side hot and not all the time. Most set it to run/ cycle on/off in the morning and evening for showers, etc and off during the rest of the day and night. When on, the temperature sensor runs the pump to keep the water warm at the hot side.

Its not perfect, but its a good compromise for places where you can't easily run a return line.

i would be a little bit wary of fitting non marine 120v a/c equipment in areas prone to damp,

[sailorchic34]

Oh good point. Right... probably not good to use it in a wet head area though. Think the OP was talking about a larger boat (What I call a yacht) which probably has separate shower stalls. For heads with separate shower stalls, it would be find. Its designed for bathroom installations after all.

I forget that some people take showers inside there boats...

[Oliver L.]

Hey guys,

this tickles me to death - I actually designed and built the undersink system...

For boats there is a DC version which does not load your inverter or genset. It's called the D5 vario, and you can set it down to about 3 Watts minimum. We don't build one with a thermostat, however, so you need to wire it in series with a strap-on thermostat to shut the pump off whenever the pipe is hot enough.

In a boat recirc makes sense simply from a water savings aspect, but the added convenience is nice, too.

Oliver

[capn_billl]

If you're thinking about replumbing, if changing from 3/4 to 1/2 it sounds as if you are. Then you have a lot of flexibility in the redesign. It also sounds like the big issue is in the showers. A small inline heater, (tankless water heater), directly connected to the shower line may work, Plus you can preadjust the temp setting to comfort.

Or if the boat is mostly in colder climates, the temp bypass will be a good fix, the water will cool quickly going back to the tank anyway.

[ggray]

I'm getting too tired to carefully study these responses so I may be wrong, but there seems to be some confusion between home installations and those on a boat.

You don't need a dedicated recirculating pump on a boat; just make use of the pressure pump with a valve and relief line back to tank, as a few have suggested.I just hold the hot water line near this valve, and when it gets hot, I shut it off.

At home, I use this: Water Heaters and Tankless Water Heaters Work Better With a Chilipepper Hot Water Demand Pump System

Push the button when you want hot water, pump starts, and then shuts off when it detects hot water. It's rather noisy, though.

[tallyhorob]

Originally Posted by twistedtree

One down side of HW circulators is that they can result in heated cold water. We have this in out house, and the instant hot water is great, but when it's on I have to run the tap for a while to get cold water. Mind you, I like my drinking water cold, not luke warm and not warm. In our case we have a dedicated return loop for the hot water, but the cold water pipes still get heated by proximity to the hot water pipes. Using a mechanism that returns the hot water through the cold water pipes will be much worse.

Lessons learned are to 1) use a dedicated return loop, and 2) be sure both hot and cold pipes are well insulated.

Agreed, I install these all the time and the under sink ones kind of suxs, but if you can not get the the lines they its better then nothing