New Water Heater: Supplied With Energy Restriction Perhaps ? Also, Question On Inlet Valve For

[Robert11]

Hi,

On the inlet cold water pipe to the typical cylindrical, vertical, gas fired hot water heater:

Are most plumbed in with a globe valve, so the water to it can be completely shut off ?

I saw a diagram where they said to use a gate valve. This doesn't make much sense to me, as although a gate valve would allow a consideably greater flow thru it when wide open (less p drop), the globe style allows for a full shutoff, if needed.

Our new water heater seems to have a lesser flow thru it than our old one of ten yrs ago. Wife is quite upset. On looking thru the web, I came across this gate valve picture.

So, which style is commonly used for this application, these days ?

Also, are these new heaters supplied with any kind of "Energy-Saving" restriction like so many newer shower heads ? Any thoughts on why the thruput flow might be lower on the newer one (same size, different mfg.) ?

Thanks, Bob

[BobK207]

Bob-

I use ball valves (usually 3/4") on inlet AND outlet; makes changing the water heater NEXT time a snap! Just close both valves, drain water heater, place w/ new unit, turn on valves....you're done. Not water leaking back from the house to make a mess!

Globe valves can be used to throttle but why in a water installation?

Gate vavles give good flow when fully open but don't have the postive off like a ball valve.

Don't know about water heaters having flow restriction on purpose, never seen a situation where the w/h was the restriction;

old, rusty or too small pipe yes; water hear, no

age, condition & material of pipes?

who did the install? could they have introduced something to the pipes?

cheers Bob

[Paul Franklin]

I use ball valves for everything now. I've just found them to be higher quality and more reliable. Gate valves are intended to be fully on or fully off. Ditto the other posters comment to put one on both inlet and outlet.

I have noticed that some gate valves are not "full flow" meaning the bore through the valve is less than the pipe ID. If this type of valve was used, that could limit flow, but I doubt you'd notice it if only one faucet was in use. This is also true of ball valves, you have to make sure it is a "full flow" type. You can tell just by sighting through the valve while it is open (before it's installed, of course). If the bore is more than a little less than the ID of the pipe, it will restrict flow somewhat.

I am not aware of any flow restrictions in new heaters. If you notice reduced flow after changing out the heater, it may be that your aerator screen at the faucet has gotten plugged by "gunk" released when the piping was disturbed to change out the heater. This is not unusual when plumbing is disturbed. Try unscrewing the aerators and cleaning the screens. New heaters often have bits of junk in them from manufacturing as well, and if the installer didn't flush the tank a little through the drain, then those bits could be plugging the screens as well.

HTH,

Paul

[Chris Lewis]

According to Robert11 :

They are plumbed with shutoff valves, and globe (washer) valves are usually used because they're cheap. They should be done with full aperture valves, such as gate or ball valves.

Gate valves are somewhat older technology. While they can shut off completely (ours do), they're not as reliable as newer ball valves, and these days ball valves are preferable, easier to use, and usually cheaper.

When our water heaters were replaced, the installers replaced the shutoff valve. They used globe valves, and discarded the existing gate valves. Grrrr. That was the cause of the flow restriction, and I put the gate valve back in.

[dicko]

The more efficient water heaters also have a "heat trap" installed on the exit port. It's closed when no water is flowing and open when a faucet is turned on. It's nothing more than a plastic flap stretched across the pipe.

Its possible that it could restrict the flow slightly. Miine has one and I never noticed any difference in flow.

dickm