Hot Water Recirculartor?

mburke911 · 01-25-2008, 10:42 AM

Hello,
Totally off topic question. Does anyone anything about hot water recirculators? Our master bathroom is on the opposite side of the house to the hot water heater and to get the water warm we waste about a gallon of water whenever anyone wants to take a shower. With the droubt we have essentially stopped using the master bath (the other bathroom is right below the attic mounted water heater). I am really sick of this so I have been looking into hot water recirculators to see if they might solve the issue.
Home Depot sells two models and they look fairly straight forward to install. Are they worth the money (~$250)? Do they really keep the hot water readily available?

Any one with first hand experience would be greatly appreciated.

Thanks

Mark

Jim Murphy · 01-25-2008, 10:56 AM

I thought about this. I have a well, but I'm still concerned about water usage.

I have more of a problem with the washing machine and dishwasher/sink than the bathroom, but whatever needs are farthest from the heater are problematic.

There are two methods:

1) a recirculating pump that requires you to push a button to move the water around. This works only when you need hot water and takes around 30 seconds to get the HW to you.

2) a system that works by gravity and uses the density/temperature curve of water to continually circulate unheated water back into the supply. This one works all the time (although a manual valve would allow summertime shutoff.)

Since I pay outrageous amounts for propane to heat my water, and nothing for the water itself, and being naturally cheap, I think my time and effort will be better spent insulating the hot water lines. With or without the recirculation, when you close the tap you leave gallons of expensive heated water to do nothing more than slightly warm the crawl space (or slab), a most inefficient use of hot water. There's no way to avoid that problem, though.

I shall watch this thread with interest to glean from the experiences of those who have done it.

BumoutBob · 01-25-2008, 11:11 AM

My last new house had the same problem. It was plumbed with plastic, and even in a heated basement the pipes absorbed a lot of the iniatial heat of the water. I insulated the hot water pipes and this helped deliver hotter water, but that doesn't solve your problem.
What about installing a small water heater near the Master bath? It might be cheaper to do than the recirculator. If the regular heater is fed into the small unit you would have 5 gal of hot water close and some help as the cold line water feeds into it.

Gotcha6 · 01-25-2008, 11:27 AM

We use these a lot in medical upfits. They work quite well & can be purchased with either a timer or a thermostat. I'd recommend a thermostat. You never know when you might need the hot water & the power draw is minimal. They are a must on large buildings with scattered fixtures. Just tee into the hot water line farthest away from the tank & pump this water back to the cold intake on the heater.
Point of use heaters are also becoming popular for this reason & they can be mounted below a sink if the power is there. Be careful with them because they work on flow & will overheat the water if not plumbed properly.

dancam · 01-25-2008, 11:54 AM

I have the same pblm w/the m. bath the furthest from the hw heater. I also have a recirculator pump that the builder and plumber suggested. It works great and the water is almost instantaneously hot. I added an electrical timer to the recirculator that turns it on at 6:30A, off at 9A on again at 4:30P off again at 6:30P then lastly on again at 10:00P off at 11:30P.

Seems like a lot of trouble but the timer is easy set and it keeps the recirculator on only when we expect to need hw.

Dan C.

mburke911 · 01-25-2008, 11:57 AM

Thanks for the responses. So one question I am not quite sure about is do the lines separate for upstairs and down at the hot water heater. I think the furthest source is the downstairs 1/2 bath but would that affect hot water in the master bath which is upstiars? If not to do this properly would I need to install two recirculators?

Can you recommend a brand? Home Deopt carries both one with a timer and thermostat. I think one of them had both so you could set it to stop working at night and restart before you start you day.

Thanks again.

Alan in Little Washington · 01-25-2008, 01:06 PM

I had the builder install a recirc system in my new house which has the master bath at the opposite end of the house as the hot water heater, except he took the shortcut and did it wrong. They installed a one-way pressure pilot valve in the water lines at the master bath end of the water lines. It connected the the hot and cold lines. When the timer operated recirc pump turned on, the increase hot water pressure would force the pilot valve to open and hot water would flow to the master bath and into the cold line which acted as a return. Very inneficient energy-wise, and you also got hot water instead of cold from the faucet if you wanted a drink or to brush your teeth- hate that! This setup was like those used for after-the-fact installation in houses built on a slab.

I replumbed the system. I removed the pilot valve and installed a new hot water return line from the master bath back to the hot water heater. I also installed a one way check valve to ensure the returned, now luke-warm, water would go into the hot water heater and not back up into the cold water supply line. I also wrapped both the hot water and hot water return lines in foam pipe insulation.

Here are pics of my hot water heater and recirc pump. The pump is a Grundfos and has an integral timer. The two lines coming in from the right are the (cold) supply and the hot (luke warm) return. I installed cut-off valves (partially visible) as well as check valves (not visible)

Here is a close-up of the 110V pump w/timer. I can't say anything about the brand, but it works and is quiet. The timer allows multiple settings as short as 15 minutes over a 24 hour day. I hope this helps.

scsmith42 · 01-25-2008, 10:59 PM

A friend of mine had a very simple system in her house, and it did not require a recirculating pump.

Basically, at the end of the main hot water trunk line (at the furthest point from the water heater), a smaller line was plumbed back to the water heater. The manual drain valve was removed from the lower side of the water heater, and a "T" valve insterted. The manual drain went back in to one side of the "T", and a one-way valve went into the other. The return line was attached to the one-way line.

Basically, convection within the water heater forced the hot water rise within the heater, which in turn caused it to circulate through the line, returning at the bottom of the heater. The one-way valve kept things headed in the right direction.The lines were insulated to minimize heat loss.

Simple and effective - hot water was available within a second or two even 60' away from the water heater in her house.

Scott

DavidF · 01-26-2008, 01:39 AM

Originally Posted by Gotcha6

We use these a lot in medical upfits. They work quite well & can be purchased with either a timer or a thermostat. I'd recommend a thermostat. You never know when you might need the hot water & the power draw is minimal. They are a must on large buildings with scattered fixtures. Just tee into the hot water line farthest away from the tank & pump this water back to the cold intake on the heater.
Point of use heaters are also becoming popular for this reason & they can be mounted below a sink if the power is there. Be careful with them because they work on flow & will overheat the water if not plumbed properly.

I am considering a Point of use heater for our Master bath, what are the plumbing mistakes that you mention?

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