153.331140 new Kenmore Gas Water Heater low heat ?

[radar325]

Good Morning All and Greetings Grand Master

I installed the above water heater about 2 and a half months ago. I was really pleased with the performance and all was well. This morning after my wife and I taking normal length showers, I noticed that the water wasn’t as hot as it has been. I’ve been running it on the “C” setting (which is one “notch” below the hottest setting) I like my hot water HOT. I checked its operation. The burner was on and the red LED was blinking at the normal rate indicating that the water heater didn’t recognize any faults. It was quite warm in Ohio yesterday (although I couldn’t see that affecting the water heater) and I did open a valve to the upstairs bath that was only partially open since the install. (the install went late into the evening and the valve was an oversight) I’m pretty sure there are no significant leaks as I would have heard or seen water leaking and the needle on the water meter wasn’t moving. That was all I had time to check this morning. The manual suggests sediment, leaks, and low gas pressure as possible causes along with insufficient combustion air, a blocked flue, base ring filter blocked with lint and or dust and improper calibration. The flame was a nice blue color and seemed to be the correct size. The tank came with a Honeywell control that is powered by a thermopile. I thought this was a “cool” design. I wonder if this may be a little too high tech. Has anyone experienced this problem with this model? Thanks (or should I say Tanks)

Brian

[radar325]

I don’t know if this is relevant, but I used an existing gas regulator that had been on the water heater line for years. I’m not even sure if this is even needed but I left it on anyway. Do those fail? The install manual doesn’t mention the use of a gas regulator. I replaced the last heater because it failed totally.

[jumptrout]

Let the heater heat fully and cycle off.

Open a hot water valve and place a thermometer in the water stream to determine actual temp.

Run this way for 15 minutes and watch for a temperature drop while someone observes the heater to cycle on.

The "C" setting should about 125-130 degrees.

If the water runs out too soon you may have a dip tube problem.

All gas supply line must have a regulator.

You may need to use a manometer to check the water column pressure on the regulator.

[radar325]

Thanks Jumptrout,

I’ll give it a go as soon as I get home after work today.

Is a dip tube a big deal to fix? There were some “cheesy” plastic filters that I noticed upon install.

One of them turned sidewise and looked like it was going to be a problem, so I just pulled it. The filter on the output is still there. I have the dielectric fittings on the tank and lines, so it would just be a matter of wrenching and draining. Seems like it is always something………around the house.

[radar325]

By the way you are quite correct!! I did measure the temperature the day after the install and it read 135 degrees (with a meat thermometer ) that’s all I had at the time.

[jumptrout]

Check the temp again to see if it has changed.

[Bullstok]

There were some “cheesy” plastic filters that I noticed upon install. One of them turned sidewise and looked like it was going to be a problem, so I just pulled it. The filter on the output is still there.

i would be surprised if those were filters installed inside the ends of the pipes on your water heater. filters would clog pretty fast unless the water was very clean and low on minerals. most of what i see are a rubber flap type heat trap. they don't allow as much heat to escape the water tank through convection (heat will not rise through the water in the pipe if the water cant flow around in the pipe). it is a part of the way manufacturers get a slightly higher efficiency rating. (and they restrict the flow some thanks to the little hole for the water to go through)

back to the problem: does your incoming cold water temperature vary at different times? some municiple water supplies or even private water supplies change temp with the weather or useage. if the incoming water is colder than normal you will get less first hour capacity from the heater. usually water supply temps dont fluctuate much though, it depends on your situation.

Edited March 2, 2012 by Bullstok

[radar325]

Thanks Bullstok,

I’m wondering about the gas supply line. I bought this house from my Dad years ago.

There is a 3/8 inch gas line teed off of the ½ inch line that runs through the basement and supplies the furnace. That ½ inch line also goes up to the kitchen for the stove. (although we weren’t cooking anything in the morning when I noticed the lower temp.) The 3/8 inch line goes to the water heater regulator and then to the water heater itself. The regulator hasn’t been replaced. What is the lifespan on a gas regulator? Would it be worth the effort to change the pipe over to ½ inch? It is only about a 6 or 7 foot run that is the smaller size. I have the ability to thread pipe. I'm not sure about the incoming water temp. The day when I first noticed the lower temp was a day after we had an unusually warm day prior.

I measured the temp last night after work and we had 145. But this morning after two showers it was around 128.

This tank is only two and a half months old and it is only the two of us living there. I think it should be able to keep up.

Brian.

[jumptrout]

128 after 2 showers is not bad at all..

Yes,you should replace the 3/8 with 1/2 hard pipe to the regulator.

Also install a drip leg at the regulator.

[RegUS_PatOff]

... I installed the above water heater about 2 and a half months ago.

...This morning after my wife and I taking normal length showers,...

1) how was the previous Water Heater performance ?

2) what's a "normal length" shower time ?

[radar325]

Ok,

I followed Jumptrout’s instructions. I let the water heater cycle off. I went to the wash tub in the basement (about 8 feet from the heater) and opened the hot water valve. I borrowed a calibrated temp probe from work and set it in a 1 quart plastic measuring container. The valve was opened near max flow and here are the readings. Initial temp. 161 degrees, after 5 minutes 149 degrees, 10 minutes 91 degrees and at 15 minutes 59 degrees. The incoming water temperature was 38.5 degrees. The heater turned on within seconds of the test and remained on. There were condensation droplets hitting the burner at the end of the test and the flame was mostly orange at that time. After about 20 to 30 minutes after the test the flame was returning to a mostly blue color but had orange tips.

Well, what is the consensus at this point? Do I have a water heater problem? I would say our average shower times are about 5 to 10 minutes. (seems like women take longer……)

[Bullstok]

If the dip tube was shot the gas valve would not open so soon in the test, I would expect. 38 deg is pretty low, that makes a 123 deg rise to get your 161. I would think the heater just does not have enough ass to heat the water fast enough. u should measure your water flow into a 5gallon bucket (see how long to fill it and do the math to get per minute) to get the gpm used by your shower. I am also curious as to how much you increased the flow of hot water by opening that valve completely... But no residential tank heater will sustain that kind of temp rise over a long time at even a low gpm. I didnt look up that model, I am guessing it is a 40gallon with around a 35k btu burner? That would sound close for your numbers. But even two condensing (read: more efficient) tankless heaters @ 200k btu each could barely pull off a decent gpm flow in ur situation.

I looked it up, it's a 40k btu so I missed it some. First hour recovery is 40gallons @90 deg rise. U need more heater or less water flow.

Edited March 6, 2012 by Bullstok

[radar325]

Thanks Bullstok, I appreciate your help with this. I consider myself pretty capable, but there's a lot I don't know. Sweating pipe and hooking stuff up doesn't make you a plumber, and there's no substitute for experience............

The heater is in good health then?

With the 38 degrees coming in I might just crank the temp to max for winter time. Being that it is just the two of us we would both be aware of the “hazard” potential. My thinking being that with say almost 200 degree water, you would mix less of that with the 38 degree water to get the shower temp that (the Mrs.) we are shooting for. I’ll give it a try…..