Drain pans - good for home, bad for water heater?

christopher_2008May 21, 2008

Something I have noticed from time to time is that water heaters in drain pans are rusted on the bottom usually visible around the seam where the outer jacket meets the jacket pan.

If you look at a typical drain pan, particularly where the drainpipe (connector) goes through the side of the pan youÂll notice that the lowest part of the drainpipe is about ¾' above the bottom of the pan. If water should enter the pan, which can happen from expansion or minor leaks, the pan will retain about ¾' of water before it starts to drain out. The water heater can be sitting in water for an indefinite time.

I have repaired (or condemned) propane (donÂt know about natural) gas water heaters that due to retained water blocking the combustion chamber fresh air vents have burned so rich that the combustion chamber and flu were heavy with soot causing a fire hazard or at least an unnecessary service call. On the older non-FVIR water heaters this has caused the flame to roll out through the service panel melting the plastic knobs on the control and discoloring the side of the heater. On the FVIR heaters this can cause them to bump the limit and shut down usually requiring a service call.

Also, I have seen water heaters installed on a non-level surface and the makeshift ways that have been used to attempt to level them.

Has anybody else experienced these problems? If so did you come up with a solution for them? Is there a need for a product that would slightly raise and level water heaters?

Thank you, Chris


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Quote:"If water should enter the pan, which can happen from expansion or minor leaks".

The only way that water could end up in the pan as a result of expansion would be if the T&P valve was discharging into the pan. The plumbing codes expressly prohibit discharging the T&P valve into the pan. T&P valves must have a dedicated drain line which discharges either into an approved indirect waste receptor or outside the structure therefore if the water heater is installed to code standard we should never see any water in the drip pan as a result of expansion.

If water is entering the pan from leaks it is a result of either faulty installation or a lack of periodic inspections and routine maintenance as outlined in the manufacturers installation and operations manual.

In my humble opinion homeowners at large should not be compelled to invest in materials or accessory equipment to compensate for the neglect of a few.

On the other hand, if one does desire to elevate the base of the water heater above the pan nothing stops you from setting three common bricks in the pan and installing the water heater on top of the bricks.

    Bookmark   May 22, 2008 at 8:39AM
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Thank you for your response. My humble experience has been that water heaters are probably the most depended upon but most neglected appliance in the home. As long as there is hot water people typically don't think about there water heater and don't maintain it. Unfortunately, my experience has also been that these are not the, "few" rather, the many.
Maybe the larger picture is to understand that things are going to happen regardless of codes. If we took a simple precaution in this situation then perhaps we wouldn't have to be replacing so many water heaters needlessly. I'm thinking about our natural resources and conservation.
In 2006 almost ten million water heaters were sold in this country. I don't know how many were replacements for those replaced prematurely, but knowing human nature, it was probably a larger rather than smaller number. Whatever the amount it was unnecessary and a waste.
Thanks again, Chris

    Bookmark   May 22, 2008 at 9:46AM
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I don't see any reason a normally operating water heater would have any water in the pan.

I would like to know what plumbing code expressly prohibit discharging the T&P valve into the pan. In IPC you are allowed to discharge the relief valve to the floor.

    Bookmark   May 23, 2008 at 11:53AM
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"TPRV may not discharge into the drain pan"

International Residential Code IRC-2803.6.1
Uniform Plumbing Code UPC-510.8

    Bookmark   May 23, 2008 at 12:50PM
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Using the bricks may also make the drain valve of the heater more accessible for attaching a hose. In some cases, the rim of the pan may interfere with hose attachment.

    Bookmark   May 24, 2008 at 9:46AM
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Previously I stated that a water heater TPRV(Temperature/Pressure Relief Valve) may not discharge into a drip pan and Funycide argued that the IPC(International Plumbing Code) will allow us to discharge the TPRV directly onto the floor. While that may seem like a contradiction in fact all three national plumbing codes, IPC, IRC & UPC will allow us to discharge a water heater TPRV directly on the floor, subject to some very specific conditions.

If a water heater is installed in an attic, over a wood floor or over any floor that might be damaged by discharging water the TPRV valve is required to be piped to an approved indirect waste receptor. The approved indirect waste receptor may be a line extending outside the building or it may be a line discharging into a utility sink or floor drain. If the line is extended to a utility sink or floor drain the lowest portion of the discharge line must remain a minimum of 2" above the flood level rim of the sink or floor drain.

If the line is extended outside the structure the discharge end of the line must terminate vertically downward. Under the IPC & IRC the discharge end must be within 6" above grade at the point of discharge. Under the UPC it may be within 6"-24" above grade.

If a water heater is installed in an unfinished basement or crawl space the TPRV may discharge on the floor providing the basement or crawlspace is equipped with a floor drain or sump pump receptor.

In instances where the water heater is installed in a basement or crawlspace below grade and where there is no floor drain or sump pump receptor the TPRC is to be removed and a WATTS 210 gas shutoff installed in its place. A pressure relief valve is to then be installed on the hot water distribution system at any convenient point above grade where the pressure relief valve can be discharged into an approved waste receptor.

The diameter of the TPRV discharge line MUST remain equal to the diameter of the TPRV discharge outlet. Under no circumstance may the line be downsized.

There must be a continuous ¼" per foot pitch for all horizontal piping in a TPRV discharge line.

There may be no traps or valves on the TPRV discharge line and there may be no treads or fittings attached to the discharge end of the line.

When a TPRV discharge line is terminated outside the structure it must be in a position of plain view and MAY NOT be obstructed by shrubbery or other landscaping materials.

In instance where a drip pan is also required, the drip pan and TPRV must have separate dedicated drain lines. Under no circumstances may the drip pan and TPRV be combined on the same line.

    Bookmark   May 24, 2008 at 3:11PM
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Thank you for clarifying the various plumbing codes regarding TPRV discharge. If all involved in this business were as diligent as you IÂm sure we would have a lot fewer installer related plumbing problems.

FunycideÂs inquiry asking where is it stated reflects my point. Assuming Funycide is a licensed plumber, or even if he is not, apparently he is involved in plumbing to some extent and has replaced or worked around water heaters enough to say, "I don't see any reason a normally operating water heater would have any water in the pan."

Yet, apparently, he did not know about the plumbing codes you recited, and, it would be safe to assume, HAS discharged TRPVÂs into the drain pan and if this is his idea of a normally operating water heater (by discharging the TPRV into the pan) has substantially increased the possibility of water entering the pan.

How many out there are like him and have done the same thing thinking that it was accepted? I see more TPRVÂs discharged incorrectly the correctly. Or, in the case of home owners doing their own plumbing work in an attempt to save money have done the same thing or considerably worse, simply because they didnÂt know better.

With this in mind a water heater that should have lasted 15 years or more is now replaced in 8. This could have been averted just by raising the water heater up so when these people, professional or not, made a mistake it still didnÂt put the water heater in jeopardy.

Codes are great and for the most part the system works. But problems are going to happen codes or not. If something can be done to foresee this possibility and others then it seems to me this is a step in the right direction.


    Bookmark   May 24, 2008 at 10:18PM
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I agree that the water heater should be elevated however I don't see the need to invent or create a whole new product solely for that purpose when bricks work fine.

In regards to installations that do not meet code I think you will find that more and more jurisdictions are requiring a permit and inspection for all water heater installations or replacements.

In some communities in my area you cannot take possession of a water heater at the retailer unless you show a copy of your permit. If you tell the retailer that you are intending to take the water heater to another jurisdiction where permits are not required they will make arrangements for you to pick it up at an outlet in that jurisdiction or they are required to deliver it and confirm the final location.

    Bookmark   May 24, 2008 at 10:38PM
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I live in a jurisdiction that requires permit and inspection for water heaters -- at least my gas unit. However, in practice it is so superficial and carelessly done it amounts to little more than a simple tax. In terms of making the installation right in actuality, I was pretty much on my own. I suspect many others are, too.

Agree with Christopher 2008.....lazypup's fine fellow...very helpful.

    Bookmark   May 25, 2008 at 1:52PM
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With regard to observing some rust on the bottom of water heaters, notably the old one that is being removed, steel rusts where both the temperature is above 50 deg and where the relative humidity is 50% or more. Liquid water is not required. Simply installing a heater scuffs the finish on the bottom of the heater. Surface rust on the bottom of the heater is not necessarily a serious matter.

    Bookmark   May 25, 2008 at 4:20PM
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There is a simple solution to the whole matter, all they need to do is encourage the water heater manufacturer to install legs on all water heaters regardless of whether they are FVIR compliant or not.

    Bookmark   May 25, 2008 at 5:56PM
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Lazy & bus,

As far as rust, the rust I am talking about is on the seam between the jacket and jacket pan and on the inside of both of these area's more easily visable on gas waters because of the service window.

The legs would be a good idea, but unless they are made from something that doesn't rust they too could meet their demise.

I just don't like seeing something that shouldn't rust, be rusted when there is a way to prevent it.

Thank you both for your input.

    Bookmark   May 25, 2008 at 8:08PM
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I would like to know how water would enter a drain pan of a properly operating water heater. Even if the relief was piped to the pan. I do not consider a dripping relief valve to be operating properly.
If just being in a humid basement is the cause of the rust then I am not sure what impact a drain pan has.

    Bookmark   May 27, 2008 at 12:03PM
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I'm home for lunch right now and need to get back to work. I will answer you when I get home tonite.
Thanks, Chris

    Bookmark   May 27, 2008 at 3:52PM
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One response to your statement/question would be to ask, if all water heaters remained operating properly would there be a need for a drain pan at all? I have seen instances where a drain pan has saved the day, the homeowner was lucky they had one. And if you have seen this it could have been because something went wrong with the properly operating water heater  some part of the system malfunctioned for one reason or other.

A drain pan is like insurance for the house in case something goes wrong with the water heater. A device that would raise and level a water heater in a drain pan is insurance for the water heater from both a safety and functional point of view.

It would be wonderful if home owners paid the same attention to their water heater as they do their other appliances. Seems to me the only reason they may take more interest in other appliances is because they see, touch and hear the other appliances, save the FAU, although it can be heard in many cases. Perhaps you would agree that many homeowners donÂt look at their water heater unless it stops producing hot water.

Most likely a water heater will work (but deteriorate) if it is sitting in water caused from a defective T&P valve, a leak from associated plumbing, a leak from plumbing that isnÂt even part of the water heater but is above, or close to it, a tank leak, back flow from an improperly installed drain line, defective pressure regulator on a closed systems etc, IÂm sure there are more reasons that I canÂt think of right now but the point is there are many ways water can enter the drain pan of a water heater that at one time was properly operating.

Properly operating is a provisional/relative term. At some point in the future, sooner or later, there WILL be a problem with the water heater, its components or associated plumbing causing a leak. This is true even if everything was done "properly" from pulling the permit, installed by a licensed professional, to finished inspected product. Of course the chances of avoiding a problem are at there best with an installation done according to the permit/inspection system.

Thank you, Chris

    Bookmark   May 27, 2008 at 10:31PM
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