Check valve for water inlet on hot water heater ?


Should I put a back flow preventer or check valve on the water inlet on a water heater ?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Thats about the last thing you want to do. Why would you even consider it?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Toller wrote:

There are (at least) 2 possible reasons for a check valve on the inlet of a hot water heater.
1 - Some municipalities require a check valve to prevent the flow of water from the house back to main.
2 - A check valve is used when a recurculating system is used to prevent long waits for hot water at fixtures far from the heater.
If you do use a check valve, you should also use an expansion tank in between the valve and the water heater. If you don't, you run the risk of having water leak from your pressure relief valve when the water heats up and has no place to go due to the check valve.
Toller wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

That depends. A house that I owned up until 6 years ago was on top of a hill. When the water supply failed (e.g. when there was a fire on my circuit and the pumpers went whole hog) the water from the tank got sucked back into the mains and the heating elements on my heater burned out ... happened several times ... I was forced to install a check valve.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I am tempted to say that is impossible. Even if a siphon could be established, if no taps are open the water in the heater couldn't get sucked out.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Toller wrote: - I am tempted to say that is impossible. Even if a siphon could be - established, if no taps are open the water in the heater couldn't get sucked - out.
I'd like to agree, but this thread seems to indicate that its possible:
http://www.askmehelpdesk.com/plumbing/water-heater-there-blow-back-valve-prevent-tank-going-dry-9164.html
Read the last response in the thread.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sat, 23 Dec 2006 17:18:58 -0500, "Charles Schuler"

That is strange. They require "backflow preventers" (2 check valves) on every water service around here. You might be able to contaminate your own water lines but your water will never get back to the street.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

As the others have asked, why? Siphoning the water tank dry sounds pretty unlikely if all taps are closed.
But anyhow, your water meter may already have one as I believe most newer meters are required to have them (<5-10 years). If your heater has an expansion tank hanging from the ceiling on the hot side, then you already have one.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
My water comes from my artesian well. I am concerned about losing heated water flowing back towards the well tank.
Thanks
Ed
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
not in buffalo ny, but if required by your local plumbing codes.
Ed wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

In most cases, no. but some towns are now requireing backflow preventors in every home. They are needed with in-ground sprinkler systems.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
buffalobill wrote:

If it is required by code, it will be required at the house supply inlet, usually where the service enters the house (unless it is part of the meter). It won't specify that it is neededon the water heater. Someone else pointed this out but I will add it again. If a check valve is placed on the heater inlet, then an expansion tank should be installed.
Harry K
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.