Temp and pressure drop in Gas HWH

[BigEdgar]

Hi,

We've got a 50 gallon gas HWH that was installed in 2005 (State is the manufacturer, model PR6 50 X0DS - see http://www.statewaterheaters.com/lit/partslist/res-gas/185507-000.pdf for details). We've never had any issues with this HWH, but last week I noticed two changes that occurred during a short period of time:

1. Temperature drop - I noticed the hot water dropped in temp (noticeable all over - from the bathroom shower, kitchen sink, etc.). It didn't get cold, but it went from "hot" to "somewhere between lukewarm and hot". I checked the pilot on the HWH and it's lit, I turned the temp up and the burner fired nicely. I turned the temp up a few ticks (from the little triangle setting to the "A" setting) and that solved the problem. We've had it set at the triangle setting for years and that temp has been fine for us.

2. A few days after issue #1 above occurred, we noticed a drop in water pressure in our shower. Again, it wasn't catastrophic and a visitor who didn't use the shower every day probably wouldn't have noticed. But my wife and I definitely did.

FWIW, it's possible that the temp drop and water pressure drop happened simultaneously and I was sufficiently distracted by the temp change to not notice the pressure change until a few days later...

We're located in the PNW and have lovely city water (not hard, not soft - awesome for drinking straight from the tap), so we don't usually have issues with mineral buildup in pipes. Our pipes were all re-done about 12 years ago and are a mix of copper and PEX.

Any thoughts on what could cause these two issues to occur at around the same time? My current theory is that there's some kind of buildup in the pipes from the HWH to the supply lines that's blocking the HW delivery, this decreasing the pressure and letting in less hot water. But I thought I'd check with the experts here to see if any of you associate these two issues with any other common problems.

Thanks for any thoughts!

 

[Reach4]

I am not a plumber.

I suggest checking the water temperature at the kitchen sink and bathroom sink. A candy thermometer would be good for that. The point is to see which hot water is affected. If all hot water is affected, post a photo of the gadget, etc connected at the output of the WH.

Even though you have city water, I would flush the tank sometimes. I am not saying that is causing this problem; it is not. But it's been 12 years, I suspect. Water heater flushing can be done different ways. The simplest is to
1. Turn off the WH water, and put the WH in vacation mode, if it has one. Otherwise off.
2. Open a hot water tap to pass air.
3. Drain the WH completely. Usually you would use a hose to direct the water.
4. Turn the water supply on fully for a few seconds, and turn off. You are trying to cause turbulence to the bottom of the tank.
5. Do steps 3 and 4 several times. If you have a way to monitor the drained water, you could judge by what you are getting out.
6. Turn the water and WH back on. Close the hot water tap once the air has been expelled and just water is coming out.

 

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[BigEdgar]

Reach4 - thanks for the thoughts, that sounds like a good call. I'll give that a whirl this weekend. I appreciate the detailed steps - that will definitely help!

 

[Jadnashua]

A typical gas WH has a warranty of around 6-years...some a little more, some a little less...IMHO, they do that for a reason, on average, they'll last that long, but anything more is a bonus...yours appears to be 12-years old. IOW, you're on borrowed time. If it has never been flushed, and you've not changed the anode rod, it's probably not healthy. Those cost-free things may or may not buy you anything, but with a WH that age (electric, tends to last longer than a gas one), budget for a new one.

 

[MACPLUMB]

Check if you have MOEN style faucets turn off the shut off valves under the sink see if that makes a difference,
2. Moen has a tendance to bleed over cold into hot water
Example if you have a Moen tub/shower valve and you run the water in kitchen you get luke warm water

 

[Dana]

When the dip-tube on an old water heater corrodes away and drops off or becomes shorter, the incoming cold water is no longer directed to the bottom of the tank, but short-circuits some of the flow to the outgoing hot water port, lowering the water temperature.

When you say it's losing pressure, you probably mean it's lower flow, which could be from freed up lime-grit deposits or corrosion crud from the tank collecting in the shower head.

Most 6 year warranty tanks have either no sacrificial anode, or an extremely stubby one. If it has a full anode it'll usually have a 10 year warranty. It's not worth spending money or much time diagnosing a 12 year old water heater. As long as it's not leaking you can crank up the temp a bit and limp along with it for awhile, but at age 12 it's gone a normal lifecycle. Even though some will go 18-20 years, many don't make it to the 10 year warranty mark. The pH of the water and the total water volume used are bigger longevity factors than time.

 

[Dj2]

Inevitably it may be time for a new WH.

 

[BigEdgar]

Terrific suggestions, everyone. Thank you all for the feedback! Sounds like it's time to be proactive and just get a new WH, so that's going to be my next home improvement project.