Water Heater too hot? (Not the water!)

Hello all-

I went into my utility room earlier this evening and it seemed a bit warmer than normal. I touched the top of the water heater and it was hot. I am not sure if this is because we were using a particulary higher amount of hot water, but I can say that the hot water happened to be running for a bath at the time. The thing that seemed a bit peculiar to me was that the plastic "washers" that fit in the hot and cold water "pipe holes" and the sacrificial anode rod were actually melting. Is this a sign of something amiss? The water heater is gas and has been in place for around 10 years The melting appears to be occuring nearest where the exhaust exits to the flue. I have included pictures to illustrate what is happening. In case the pictures aren't in a good resolution to tell, this plastic is actually in a melting state - soft to the touch-almost liquid. My biggest concern is if this may be a safety issue. As an added note, the flue takes a hard left horizontal turn and runs about 18' before heading vertical again and running up the chimney. I would also like to know if there are any potential safety issues with this configuration. I appreciate any feedback!

Thanks,

Tony

Do this quick check to see if you have a draw problem: With the WH burner running, Light a match stick, then blow it out. You now have a smoky stick. Hold it near the draft hood ; the smoke should NOTICABLY be drawn into the hood. If it is lazy, or worse yet it it seems to blow outward, you have a very serious carbon monoxide issue. get it looked at immediately.

I have always been fairly paranoid about carbon monoxide, and I have detectors in several areas of my home. I have one in the utility room that has never registered anything (it has a digital display). This being said, I performed the test with the match and I would say that we definitely have a draw issue. I performed the test after allowing the flue to warm up for a minute, and noticed that the extinguished match smoke did not get sucked up the chimney. In fact, I tried a test to see what would happen to the flame of the match without blowing it out. Well, the force of the escaping exhaust blew the match out before I came within an inch of the draft hood. I am guessing that this is not a good thing.

To add a bit more history, we have two fireplaces in the house, including one in the basement. We had a history of smoke backing up into the house during fires, described to us as having negative air pressure in that part of the house. We switched to gas logs, and though we don't have the smoke, I am now guessing due to this issue with the water heater, that simply having gas logs isn't the cure. I am also guessing that the problem that we are having with the water heater is related to the problem that we were having with with the natural fireplace in the basement. (perhaps this goes without saying - a "duh" on my part - even.)

We already have a high efficiency furnace that I think draws most of its fresh air from outside. We also had a combustion air makeup device installed near the furnace at the advice of our HVAC technician. This doesn't seem to make a difference. (Mechanical device that pulls fresh air from the outside, into the utility room containing furnace and water heater) FYI- the utility room is in the basement.

Is the answer to this problem going to be replace my current water heater with a direct vent model? As I stated in my original post, it seems like the current water heater has a very long (I think ) flue run.

Thanks again for the assistance!!

I suspect that something has plugged up the vent or there is something that is causing low pressure in the area where the water heater is located.

It could also be a problem with air flow or a wind condition at the stack outlet causing some back-pressure.

Check your flue to make sure it's drawing a draft properly. I've seen this once before and the fix was to extend the pipe after it exits the roof a few feet higher. You might also have an obstruction in your flue somewhere. Is this flue shared by anything else?

Do the match stick test as explained by jimbo. That's where I'd start.

flue

If that long flue is regular single wall vent pipe, it could be "cooling off" before it even gets to the chimney, thus dropping back onto the heater.

IMO, you have an issue with the 18' + flue at 4" diametre. Thats a heck of a long hrizontal distance for the CO to be traveling. If you tried to increase the diametre of the flue, it may help to get rid of the exhaust alot quicker.

Just a thought

The water heater flue runs 18 feet horizontally and - well - I am not exactly sure how far up, but it is a two story house. There are three separate flues that are contained within the chimney. One for the water heater and two 9" stainless steel flues that are used for the vented gas log fireplaces. (Formerly natural) The basement fireplace had a backdraft problem, and the flue is 9 inches (and ran at least 18-20 feet less), so I am guessing that increasing the flue diameter might not work for me.

A suggestion was made to me by my HVAC tech that it may be necessary to remove the vented water heater and replace it with a direct vent unit because of the negative air pressure/flow in the basement. It never occurred to me that the extreme heat around the draft hood was related to this, as well.

Looking at my vented gas logs in the basement, I have discovered a higher amount of soot on the logs than in the upstairs fireplace, and it was also suggested that this was due to a lack of combustion air due to the negative pressure/flow. (Forgive my terminology, if this is not quite right.) Putting all of the evidence together, I may need to figure something out with the gas logs, too. I'll leave that for another forum.

All of this being said, would a direct vent water heater be the way to go, or would I still run into potential issues?

I really appreciate all of the comments. I have been reading through some of the other posts, and easily determined that this is a great site with some valuable experts on board!!

-Tony

A direct vented HWT would be your safest bet.. Over 18 feet of horizontal and 3 storeys of flue pipe is way too much for any hot water tank.

although, I have seen some conventional commercial units that are assisted with a blower motor
(not direct vented), but never installed one myself.

Would I run into any combustion air issues with a direct vent (or tankless) water heater? (because of the lack of air flow in the basement) My concern is that even though I take care of the venting issues, that the new water heater would not run as efficiently as it could or should. I was thinking that it should bring enough fresh air, but I would like to be sure.

here is a couple of units to see your options. I'm not sure how much air circulation or cumbustion air you have available. It would have to be assesed on site

I may have been confused when using the term "direct vent" - I think that I was referring to "power vent". (I could just go through the wall) I believe that the power vent eliminates the need for the long flue run, but it wouldn't eliminate the issues with the lack of proper combusiton air. I know a little about the tankless water heaters - would these be considered "direct vent"?

Is there actually a direct vent -say - 50 gallon water heater? I will research based on the information given here as a start.

if you have a lack of air with power vent or direct vent, What I have done is poke a hole in the exterior wall with a fresh air intake cover (with a grill to keep rodents from nesting) and ran a duct to the vacinity of the gas fired appliance


50 gallons are available

I think that I may have found a model that will do exactly what I need, given the variables in my house - please let me know if this is a good choice:
http://www.bradfordwhite.com/images/shared/pdfs/specsheets/102B.pdf

Is this a good option for a water heater, NOT requiring electricity?:
http://www.bradfordwhite.com/images/shared/pdfs/specsheets/103b.pdf



Power Vent, Closed combustion venting. (I think that I finally found the proper terminology!)

Any other options that anyone could provide is much appreciated!

either one is a good for your application

You might want to look into heat recovery ventilation systems...these allow exterior air to come into the house without losing all of the conditioned air...they have a heat exchanger in them to temper the air coming in so it is close to that which goes out. They usually also have a barometric damper in them to bring in extra air if needed that is exhausted by combustion devices.

As mentioned earlier, if you don't have CO detectors, I wouldn't sleep until I picked up one or more. They're cheap, and can be plugged in and work immediately (well, you need to put in a battery for backup, but that only takes a minute or so). I sort of like the Kidde one - it shows a digital readout which could alert you to a low level that may not set the detector off, but still indicate you have a problem. The others I've seen only have an alarm. If it doesn't read 00, you've got a problem.

I have several CO detectors scattered throughout the house - particularly by my fireplaces, in the utility room that holds the furnace and water heater, and in the kitchen. Two of the detectors are by Kidde, just as you described with the digital readout. Fortunately both of these detectors read "00", but this is not as comforting as one would think after running that match smoke test by the draft hood.

I do have a combustion air makeup device in the room, but I don't run it all of the time. When I ran it, it didn't seem to make a noticeable difference in the venting. It is supposed to mix the air from outside with the warmer air inside, but I am guessing that these cold Michigan winters gave it quite a challenge. The air was always really cold - so much that it acted like an air conditioner while it was on. (Probably helped with combustion air, just not the exhaust venting)

Does anyone have any recommendations on the brands of water heaters that do both direct vent AND closed combustion? I have two options identified - both by Bradford White. One requires electricity and one doesn't. I am not sure that I could go wrong with either one, considering that it is a Bradford White. (At least from what I have read in this site!!) The links to the two I found are listed previously in this thread.

The closed combustion ones I've read about utilize a fan to move the air into and out of the burner, so they'd need 110vac available.

I think some of the better heat recovery ventilation systems can recover in the 90% range of energy in the air exchange, so shouldn't be too problematic. Most are designed to be incorporated into the heating system ducts, so that would re-condition the air before you noticed.

Check Sealing of RETURN Air Ducts of Forced Air Furnace.

I have seen this exact problem in my home and it was due to improperly sealed RETURN air ducts on your forced air furnace.

Is the furnace running when you notice the backdraft??

Try opening the door from the first floor to the basement when furnace is running??? Does the back draft go away??? Do you notice rush of air into basement when you open door??

Try closing door from first floor to basement till about 1/4 gap and see if airflow into basement pulls down shut. This means too much RETURN air is being pulled from basement causing the "negative pressure" and the backdraft.

Adding power vent heater will not solve your fireplace problem and makeup air unit doesn't supply nearly enough to compensate if furnace blower is drawing return air from unfinished basement.

Solution, was to seal the heck out of RETURN air ducts so that all return air came from 1st and 2nd floor spaces.

During this time I also had carboon monoxide detector right near furnace that never triggered. This condition occurs when furnace running while hot water running and since air (a lot of air) is being moved the C0 doesn't accumulate enough to trigger. Furnace turns off, water heater stops backdrafting and all is well....so no CO accumulates.

These are good suggestions - I will check it out.