Home>Discussions>PLUMBING>Hot Water Flow is Poor
14 posts / 0 new
Last post
dbogart
Hot Water Flow is Poor

Hi guys,
My wife and I bought our first house a few months back. Over the last month or two, I have noticed the hot water flow or pressure is getting less and less. This is noticed all over the house and not just in a sink or shower etc. The cold water flow is satisfactory.

I have recently flushed the hot water heater , it only seemed to have a little color to the water briefly. It didn't help the problem. We have city water. The house is 1890 with an electric hot water heater and copper pipes.

Thank you for any help you can give me on what next to do.

David

Fencepost
Re: Hot Water Flow is Poor

If there is ANY galvanized steel pipe or fittings in the system (such as a nipple installed at the water heater) it may be corroded nearly to the point of completely blocking the flow of water.

Another possibility is a blocked valve. If you have any "compression stop" type valves -- the handle visibly screws in and out; they have a rubber washer that mates against a brass seat -- these typically have a much smaller orifice than the diameter of the pipe and can get plugged quite easily. If possible, replace with a full-port ball valve or a gate valve. (On a gate valve, it will take several full turns to open or close, and you won't see the handle screw in or out. A ball valve has a lever handle and is one quarter turn from on to off.)

DO NOT use a plastic valve. They are junk.

dbogart
Re: Hot Water Flow is Poor

hi, thanks for your reply. I do not see any galvanized pipes. Here's a picture of the top of my water heater, is this what you mean by a compression valve?

dbogart
Re: Hot Water Flow is Poor
dj1
Re: Hot Water Flow is Poor

Most of your pipes are actually inside the walls, and what you see exposed is only a small portion of your entire piping system. You still could have some galvanized pipes in there.

From your photo, your shut off valve on the cold side is pretty old. You could replace it with a new 3/4" ball valve, like fencepost described.

Now to the hot side: I wish I could see under the insulation the condition of the nipple extending out of the tank. It looks like you have 1/2" pipe that splits into two. I think that your problem is here. Replace the nipple and the T - make sure you use a 3/4" pipe from the nipple to a new 3/4" T.

How old is your water heater? you can find out the year it was manufactured, right on the label.

See if this improves your pressure. If yes, let us know. If not, let us know.

dbogart
Re: Hot Water Flow is Poor

For the life of me I can't find a date. Below is a better pic of what you wanted to see and the label. Im def gonna need you guys to help if I start cutting pipe.

http://www.flickr.com/photos/gardenstatesurfer/8591433550/in/photostream

http://www.flickr.com/photos/gardenstatesurfer/8591433482/in/photostream

johnjh2o
Re: Hot Water Flow is Poor

The date on your heater is Jan. 1995. It's in the serial #. Most heaters last 6 t0 10 years. You have a new 3/4" PEX hot water line coming off the top of the heater. Did you have some hot water piping replaced?

John

dbogart
Re: Hot Water Flow is Poor

Hi john,
Thanks for your help with the date. My wife and I just bought the house two months ago so I am not sure with regards to the previous work. Would you still think the pipes off the top need replacing?
David

johnjh2o
Re: Hot Water Flow is Poor

The red 3/4" PEX hot water line with the pipe covering is new. That tells me some re-piping has been done. There may still be some old pipe that needs to be replaced. If it's galvanized that may be the cause of your problem with low hot water volume.

John

Fencepost
Re: Hot Water Flow is Poor

The shutoff valve is almost certainly a globe valve. Judging by the size of the valve body, this one may have a larger orifice than most, but it still could be the point of restriction. A replacement valve doesn't need the drain port.

I see that the both the input and output of the water heater are plumbed with 1/2" pipe. I would recommend replacing any 1/2" pipe with 3/4" that's on the cold side between the water source and the water heater. I'd also recommend replacing the output (hot) pipe so that it's 3/4" at least to that first tee just above the water heater.

One thing that you do not want to do is use galvanized pipe. It may seem easier to install than copper, but it will fail much sooner and can't be joined to copper without a special dielectric union.

If you elect to replace the water heater, install a shutoff switch near the water heater to make it easier (and safer) to service. This should be a double-pole switch rated for 20A 240V. A double-pole circuit breaker (same rating as the water heater breaker in the main panel) in a small breaker box would be a suitable option. If you don't do install a switch nearby, code requires that the breaker in the main panel be equipped with a means for lockout/tagout.

dj1
Re: Hot Water Flow is Poor

You need a plumber to sort your pipes out, to determine if you have any old galvanized somewhere out there. Replace if you find any.

Replace the heater. The cold supply side has to be 3/4" as mentioned, with a new shut off valve. The hot has to be replaced as I described in my previous posting. Run a copper line from the T&P valve of the new heater to a drain near by.

Not sure? get the plumber to do it.

Once you do all these, there is a good chance your pressure will be good.

Pages

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.