I Thought Gas Water Heaters Were Supposed to Be Good…
RichBeckman
| Posted in Energy, Heating & Insulation on
I lived for twenty years with an electric water heater that was fifteen years old at the beginning of the twenty. In all that time I never failed to get perfectly hot water. Just hot enough that there was no need to mix with cold. And always that hot. Now we live with a gas water heater. Sometimes the water is scalding hot and (more often) sometimes it is borderline cold. I am told that this is perfectly normal. If the thermostat is set to 120 degrees the water that comes out will range from 105 degrees to 135 degrees. Is this true? I can’t believe people put up with this. I miss my dependable electric water heater (and no, it did not achieve it’s consistency with the help of a balancing valve).
Replies
It's possible that the dip
It's possible that the dip tube's failed, or the unit was installed backwards.
Dan,
Are you saying that it is not normal for the heater set to 120 to not fire until 105 and not shut off til 135?
How does one know if the dip tube has failed? I assume by backwards you mean the cold water is entering where the hot water is supposed to come out, which is not the case.
I should point out that it was the plumber I called to come look at it who explained to me the normality of the 30 degree swing.
I've lived with an electric
I've lived with an electric water heater for the past 33 years, so I don't have a lot of experience with gas. I lived with gas a couple of years back in the 70s, and my MILs house (where we would frequently stay for a week at a time) had a gas heater. I don't recall ever having problems with temperature swing.
I did have trouble with our electric and temp swing at one point, but traced it down to a bad upper T-stat.
I believe the consistency of the output temp can vary with, among other things, the amount and timing of use and the recovery rate.
The more use, the wider the temp variations can be for later users.
Say the water in the tank is 120F.
Dad takes a brief shower, 5 gallons say, and the new cold water coming in (1) mixes with the remaining 35 gallons and (2) the burner comes on.
Assuming the cold water is 55F, without the burner effects, the lowered temp of the water in the tank is about 111F [(35*120)+(5*55)]/40
The burner won't be on long, so the stack effect of the hottest water at the bottom will be relatively small. (Depending on the shut off temp setting, in part)
Sis takes a leisurely shower, say 20 gallons. The new temp is about 87.5F
The burner will be on quite a while,of course, and the heated water at the bottom will rise and water >120 will "build" at the top from the stack effect. The tank temp will 'slowly' equalize thereafter.
So, If Rich gets in right after Sis, the water is "cold." If he gets in a while after sis, the water could be is >120. If he gets in even later, the water is back to 120.
Of course, the recovery rate and ground water temps will all have an effect.
And, of course, the temp sensor shut off settings will affect the process/stratification.
And, dip tubs these days have a bend at the bottom which is supposed swirl the water around the bottom of the tank reducing sediment.
I have no idea how this affects the stack and mixing effects.
Bob,
Are you saying that it is not normal for the heater to have a 30 degree swing?
Thank you for the analysis. Now can you explain why I never had this problem in twenty years with an electric water heater?
The same people are in the household as before. All of us on the same schedules as before.
Sorry, I didn't focus on the
Sorry, I didn't focus on the 30degree fact
A 30 degree swing seems excessive to me, and I've had gas water heaters most of my life (except a few years with oil...) Very little experience with electric
I'd check with the manufacturer.
====
BTW, the Bradford White test procedure for elements on electric water heaters _suggests_ that 30 swing is within specs:
http://www.bradfordwhite.com/servicebulletins/120_thermostat.asp
"b) Turn the temperature dial (with power on) of the upper thermostat to the highest setting. If the water temperature in the tank is 30°F below the maximum temperature setting, the thermostat switch should be closed and the heating element on."
But maybe I'm not missing something.
I've had gas for five years
I've had gas for five years now. The unit is only that old, and I agree with the previous post.
I'm having serious issues with the water heater. The pilot light went out the other day, so I took out the gas pan and cleaned it. It started working right away, but I started smelling gas. I've taken that door off four times and tried to reseat it thinking that the gasket had compressed, and everytime I relight it, I smell really strong gas. I'm thinking about going back to electric myself.
>> so I took out the gas pan and cleaned it.
What do you mean by the gas pan?
>>but I started smelling gas. I've taken that door off four times and tried to reseat it thinking that the gasket had compressed, and everytime I relight it, I smell really strong gas. I'm thinking about going back to electric myself.
Ahh, if the light bulb suddenly goes off, do you stick a wire in the outlet to test?
Perhaps you mistakenly stressed a gas line connection and caused a leak
Maybe not, of course.
I'm _thinking_ you've created a dangerous situation by screwing around with stuff you don't know enough about
Maybe not, of course.
Perhaps. And considering this particular brand of water heater is involved in a law suit for shoddy products (American...look it up) I've had to disassemble the thing more times than I can count as extra parts arrive in the mail.
I'll bet you I know more about this particular water heater than you.
hey! Rich!
good to see you comment/question -
you must have gotten moved?
I've got no observations about gas water heaters - other than they are suppose to operate less expensively than electrics - and some pundit, somewhere, sometime, commented on the desirability of splitting atoms to heat water 60 degrees -
always been electric in my life - and the heaters have performed very well -
D
David,
Yes, we moved late October and I've been eating your apples all winter (now that I only have to drive a few minutes to get them on Sat morning)!
Part of the differing performance may be due to the typically smaller tank size of a gas WH.
I'd guess that your EWH was a 50-gal. tank, and your GWH is 40 gal. The larger tank will give a more uniform temperature during the initial draw-down.
GWH's are sized smaller because they recover temperature more quickly. (About 40 gal/hr vs about 18 gal/hr for electric.)
Bet you can't get 6 baths and
Bet you can't get 6 baths and yes I said BATHS as in enough water for your kids to float in out of an electric in one night.
I do just that every night of the week. As long as the oldeset three don't all try to take a bath between 10-11 at night, there is plenty of hot water for all.
If the water is too hot, then you turn down the hot and turn up the cold in the shower. That solves problem one and leaves more hot water to solve problem two.
Edit:
Electrics are going to not have as noticable of a swing because they heat water much more slowly. When a gas water heater fires, it heats water quickly and obviously it heats water closest to the burner to a temp greater than 120 degrees. you are going to get greater water stratification in a gas than you do in an electric.
You should have a 3-way tempering involved as a safety limit with any water heating appliance. any failure of internal controls could result in a massive scald risk, not to mention someone fiddling with the valve, or as you are seeing stratification.
hot water can kill you. older people who slip in showers and pass out are at serious risk.
such a valve would chop off the upper part of your swing to your max temp, and it would likely prevent the undershoot you're seeing to some degree as well as it would slow down how fast you are extracting heat from the tank during that first, stratified call.
>> hot water can kill you. older people who slip in showers and pass out are at serious risk.
Not just us old folks. Young adults can and do get serious scalds as well.
And young children are far more easily scalded....
Rich
I emailed Bradford White tech support re the 30 degree fluctuation.
They responded with:
"Most commonly standing pilot heaters have a range of about + or - about 15 degrees. If it is outside of that range we would say the best to do is to replace the gas control.
"Thanks,
"XXX YYY
"Bradford White Tech Support"