I intend to update my domestic shower, and fit a pump I have been told that I may need to fit a gravity loop , what is a gravity loop ? And how do I create one?

Someone may have heard of it, Google and myself have not, In Automotive I believe they call that a "Muffler Bearing" or in electrical, a "wire stretcher".
Hopefully it is a real thing, not just someone selling a line of ShXX.
My shower works fine without one, If wrong, I appologize.

I think Pick's referring to a gravity recirculating system,(see image) This keep hot water supplied to your fixtures without a pump. To learn more click on;Hot Water Recirculating System - Installation Tips
If you need more help click on back. Regards, Tom

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I am going to guess that you are British, Irish, or somewhere on the continent. We are a people separated by a common language.

We know you want to replace or upgrade your shower, we also know that it is in a residence, not commercial establishment because you said domestic shower.

Apparently this shower or at least the drain for this shower, is below the level of the building sewer line and you also need to install a pump to get the waste water up to sewer drain. This we (USA) call a sewage ejector pump.

All plumbing fixtures have what we in USA call a trap. The trap could be call a gravity loop. It is a low spot or dip in the drain piping sort of like a half circle, for water to settle in. The water in the pipe forms a seal to prevent sewer gasses from escaping back into the house.

So if all these guesses are correct and a gravity loop is the same thing as a trap, then yes you will need one. The pit where the ejector pump sits will have sewer gasses and orders.

However this is not big deal . The trap (gravity loop) is a standard plumbing fitting. Its' installation is a normal part is doing plumbing work.

Another guess, someone is telling you that there is an additional charge for this work. If so, that's being deceptive.

Notice that these are just guesses about what you are asking and why you are asking, please clarify.

I've seen the return loop with a pump, without, I would think the hot water would rise and Not circulate?

Hi Stratmando...

Here is just one system that keeps hot water available without a pump, electricity or a recirculating line.

http://www.hotwaterlobster.com/files...ctions_1_2.pdf

However, this system does not always work well in all homes... most, but not all!

I'm thinking Tom nailed this regarding a recirc. Line with a pump.

Mark

Thanks Mark, I have seen those a couple of years ago. Didn't know if they would really work, looking at it.

Gravity hot water recirculating loops that do not require a pump can sometimes be installed after a house is built. They will only work when the water heater is below the water supply lines. This system requires that the hot water line return back to the heater after it services the farthest fixture. The return line connects to the bottom of the water heater at the drain valve. Natural convection drives the system. Energy loss is a minimum if you insulate the entire hot water loop except for the last 15 feet of pipe as it re-enters the water heater.
And that's how they work. Cheers, Tom

I guess I have a gravity recirculation system. Two story house, heater in basement. One half inch recirculation line runs from master bath, second story to tee in cold water input line. Check valve in input line and in recirculation line.
System seems to work from both convection circulation of hot water rising and from siphoning action of cold water input passing recirculation line and creating low pressure on recirculation line.

A gravity loop is the shortened version of anti gravity loop - basically a U-bend to stop the circulation of water in a system due to temperature differentials.

Hi Rodsers

It sounds like you are describing a HEAT TRAP, not a gravity loop. In looking up the term/image it actually seems to me that you are actually describing an ANTI.GRAVITY LOOP.

Here, as an example, instead of installing a heat trap nipple in a water heater, some people will install a "U-BEND" (i.e., a heat trap or anti. gravity loop?) that creates a microcirculatory loop that keeps heat from escaping up the pipes via temperature differentials. This heat trap is piped in a very specific way (not shown here).

Please direct me to a site or two so I can try to understand what you are presenting, OK?

Thanks...

Mark