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Hot Water Problem - recirculation pump?

11 replies [Last post]
Joined: Apr 14 2004

Hi. We bought our house last year and discovered that our master bedroom doesn't get any hot water during the winter, especially if the ground is wet. It doesn't get hot enough to shower even after running it for 10 minutes. The master bedroom is far from the water heater in the garage, and our radiant floor heating is no longer in operation, so we figure that without it the water pipes in the slab just aren't able to heat up for that long of a distance. Does this sound sensible? In any case, we are trying to figure out what to do. Does anyone know about recirculation pumps (especially the kind that don't require additional piping) or point-of-use systems that we might consider? Any other (inexpensive) ideas? It would be nice to have hot water this winter.



Joined: Mar 20 2003

sounds like something is broken. In our master bath it takes about one minute but it eventually is hot just like in any other house. The slab may eat some of the heat initially but it cannot do that for 10 minutes.

Joined: Mar 24 2003

We had the same issue. After we replaced all of our plumbing (over the roof) we also added a recirculating pump to the master bathroom. It makes all the difference!

Good luck


Joined: Aug 12 2004

Make sure to oil that recir pump every year as a min.

Price a new pump and you'll see why it's cheaper to do the maintenance. Plus the down time & noise it'll make while it's going.

I schedule this type of stuff (filter replacement, smoke alarm battery, disposalble camera in glove box, etc) each year at Xmas/NewYears.

The oil bottle I made up and listed in the "tools& stuff" thread makes this oiling easier (recirculation pump bearings, furnance fan bearings, etc). Most times these oiling points are behind something and have to contort just to feel them and many times can't see them.

Joined: Mar 16 2005

From the answers provided, the question is unclear.
Are you getting water (flow is OK), but it's not hot enough?? or the flow is slow (not enough pressure) but temperature is OK??
First problem is a head scratcher -- like j said, water should be hot after 10 minutes (usually within 2 minutes even in cold mornings).
If problem is low flow or water pressure, then a pump would be a fix, although municipalities (at least in NY City where I came from) is supposed to provide 20psi, enough to get to the 5th floor of an building (where I lived for 20 years).
Even 30 years of hard water or mineral scaling should not have clogged your domestic pipes for you to notice slow flow.

Joined: Aug 12 2004

This says that house has lots of water underneath it's pad, maybe even flowing water table.

Key is that during the summer when there is little water in the soil, they get hot water. But during the winter when the water table is higher, they don't get hot water.

Soil is a pretty good insulator, but when it's soaked with water, becomes a better conductor of heat. That is the only change, so pretty sure it's the soil/water conduction issue.

Since the soil has a huge mass (mother earth), it's a heat sink that draws heat, if there is a path (the water).

Ask if the "other" hot water facuets in the path from the water heater to that farthest gets cooler as the distance increases?

A recirculation pump will help, but at the cost of heating the soil up till the temp differential is smaller.....but.....that means paying lots of $$$$ to heat the soil/water.

Suggest you consult an eningeer or consider running a new line above ground.

Joined: Apr 14 2004

Thanks for all of your thoughtful responses. The water pressure remains constant and sufficient thoughout the year. It is the temperature of the water that changes. And, no, it doesn't get hot, even after ten minutes, during the winter. I am pretty sure that there is a further correlation between heat problems and ground wetness. Finally, yes, the fixtures closest to the hot water heater maintain their (reduced) heat, but as you get further away it becomes more of an issue. But the only place where we can't get any hot water is the master bedroom.

At this point, I am looking for a relatively inexpensive fix. I imagine that re-routing the plumbing over the roof would cost a lot. And besides, how would it be properly insulated on the roof? I was thinking maybe I could solve this with one of those "point-of-use" devices for the master shower. Any thoughts?

How much would it cost to replumb over the roof?


Joined: Mar 2 2004

The big expensive work when routing water pipes over the roof is moving fixtures and taking walls apart to connect the water. It should take a minute or less to get hot water in any Eichler fixture. Check your water temperature settings on the heater. This is strange because I believe you could get hot water in ten minutes running a pipe through ice.

If you have water pipes routed over the roof, please make sure the pipes are run six to eight inches above your tar roof. This can save the expense of having water pipes (and electrical conduits) temporarily removed to install one of our roofs.

Click on water pipe on this link to see what it is supposed to look like:

Joined: Aug 12 2004

Hi Randy,

GREAT info at your company's site!!!!!! Everyone should take a look.

As for the thermo dynamics of this issue....

If a house was perfectly insulated, it would only need to be heated ***ONCE*** and it would stay at that temp forever.

Since nothing is "perfect", there is some thermal conduction/convection/etc (aka heat transfer, or loss).

The "better" the conductor, the faster and more efficient the transfer of heat. Heat goes to cold.

Since there seems to be a water factor, think they have a high water table during the winter plus that water is flowing.

Then consider the burner sizing (BTUs) between the OEM floor heating system and the water heater. There is a huge difference.

With water flow, there is a continual supply of colder water that this small water heater burner must heat in order to normalize the differential so that it can deliver hot water.

I've helped one family in the Highlands who had a problem heating their whole house. They found that they had a "spring" running underneath their house and wicking the heat from the concrete pad faster than the boiler could supply heat. They ended up putting in a centralized hot air system over the roof (no foam roofing back then).

The civil engineer wanted to trench around the whole house and drain/divert the water around, but that cost vs a new heating system didn't make sense. Plus he said "most likely would solve", and that pushed their decision over quickly.

Joined: Dec 5 2006

Hi Andy,
We are encourtering the same problem (no hot water in the bathrooms) in an Eichler we are purchasing. We get hot water in the kitchen (which is closest to the water heater). Were you able to find an inexpensive solution to your problem? Thanks for any advice.

Joined: Jun 28 2003

.... ah, I had the same problem as yours (hot water taking its time to my bathroom) and I turned up the heat by about 10 degrees for the hot water heater and now I get hot water quicker.



Joined: Mar 25 2006

Most of the pump manufacs have an easy kit to cross-over the farthest sink in the line with a re-circ pump and get instant hot water. Of course it uses some energy. Cost against comfort and convenience. Your call. Installation is only about $500. I'm assuming that you have checked your water meter with everything off to be sure it's not spinning around from a bigga leaka.

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