I looked at a friends basement water lines recently and noticed that he didn't have a water pressure regulator but he had an expansion tank above his water heater. He said the guy who installed the water heater told him he needed the expansion tank to meet code. I doubt there are any backflow prevention valves unless it is built into the water meter outside.

On 10/13/2013 11:12 PM, Davej wrote:
I looked at a friends basement water lines recently and noticed that he didn't have a water pressure regulator but he had an expansion tank above his water heater. He said the guy who installed the water heater told him he needed the expansion tank to meet code. I doubt there are any backflow prevention valves unless it is built into the water meter outside.

Many are set up that way with a bladder tank Fill valve is probably
sufficient to act as backflow prevention.

On Sunday, October 13, 2013 8:12:58 PM UTC-7, Davej wrote:
I looked at a friends basement water lines recently and noticed that he didn't have a water pressure regulator but he had an expansion tank above his water heater. He said the guy who installed the water heater told him he needed the expansion tank to meet code. I doubt there are any backflow prevention valves unless it is built into the water meter outside.

The expansion tank is to prevent water hammer, has nothing to do with pressure - that is provided by the water system. The back flow preventer would be part of the water meter.

Harry K

On 10/13/2013 11:12 PM, Davej wrote:
I looked at a friends basement water lines recently
and noticed that he didn't have a water pressure
regulator but he had an expansion tank above his
water heater. He said the guy who installed the
water heater told him he needed the expansion tank
to meet code. I doubt there are any backflow prevention
valves unless it is built into the water meter outside.


Did you have a question, or are you just thinking
out loud?

..
Christopher A. Young
Learn about Jesus
www.lds.org
..

On 10/14/2013 12:07 AM, Harry K wrote:
On Sunday, October 13, 2013 8:12:58 PM UTC-7, Davej wrote:
I looked at a friends basement water lines recently and noticed that he didn't have a water pressure regulator but he had an expansion tank above his water heater. He said the guy who installed the water heater told him he needed the expansion tank to meet code. I doubt there are any backflow prevention valves unless it is built into the water meter outside.

The expansion tank is to prevent water hammer, has nothing to do with pressure - that is provided by the water system. The back flow preventer would be part of the water meter.

Harry K


You mean the water authority here has been lying to me?

On Monday, October 14, 2013 6:47:18 AM UTC-5, Stormin Mormon wrote:
On 10/13/2013 11:12 PM, Davej wrote:

I looked at a friends basement water lines recently
and noticed that he didn't have a water pressure
regulator but he had an expansion tank above his
water heater. He said the guy who installed the
water heater told him he needed the expansion tank
to meet code. I doubt there are any backflow prevention
valves unless it is built into the water meter outside.

Did you have a question, or are you just thinking
out loud?

My question would be whether such a system makes sense? Unless there is a backflow preventer out in the outdoor water-meter the expansion tank isn't going to do much of anything.

On 10/14/2013 11:06 AM, Davej wrote:
On Monday, October 14, 2013 6:47:18 AM UTC-5, Stormin Mormon wrote:
On 10/13/2013 11:12 PM, Davej wrote:

I looked at a friends basement water lines recently
and noticed that he didn't have a water pressure
regulator but he had an expansion tank above his
water heater. He said the guy who installed the
water heater told him he needed the expansion tank
to meet code. I doubt there are any backflow prevention
valves unless it is built into the water meter outside.

Did you have a question, or are you just thinking
out loud?

My question would be whether such a system makes sense?
Unless there is a backflow preventer out in the outdoor
water-meter the expansion tank isn't going to do much of
anything.

Agree. Your thought makes sense, to me.


..
Christopher A. Young
Learn about Jesus
www.lds.org
..

On Mon, 14 Oct 2013 08:06:56 -0700 (PDT), Davej
wrote:



My question would be whether such a system makes sense? Unless there is a backflow preventer out in the outdoor water-meter the expansion tank isn't going to do much of anything.

Above a domestic water heater, you are correct unless there is a check
valve. My original thinking was a boiler (often used as a water
heater also) where the fill valve would act as a check valve too.
There it makes sense.

On 10/13/2013 10:12 PM, Davej wrote:
I looked at a friends basement water lines recently and noticed that
he didn't have a water pressure regulator but he had an expansion
tank above his water heater. He said the guy who installed the water
heater told him he needed the expansion tank to meet code. I doubt
there are any backflow prevention valves unless it is built into the
water meter outside.


Sometimes there is a check valve at the water meter to prevent back flow
that could contaminate the public water supply. When the water in the
water heater expands from being heated, it will leak out of the TP valve
on the heater if there is no expansion tank. It really depends on the
practices of the utility supplying water in your area and the plumbers
will know. ^_^

TDD