dummy electric water heater question...

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Old 04-21-03, 10:06 AM
sledgmb
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dummy electric water heater question...

hi all. i'm going to be installing a 30-gallon electric water heater (shorty) in my deer camp cabin this summer. i've already run the wire and installed the circuit breaker. my dummy question is really what all pipes go into/out of the water heater? i know there is a cold water "in" and a hot water "out". i keep hearing about a "drain". is there a drain line? should this be attached to your main house drain line (graywater)?
 
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Old 04-21-03, 04:52 PM
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all water heaters need an emergency temperature and pressure relief valve that keeps the tank from blowing through the roof if it over pressures. There is a drain tube off of this that should terminate outside, near a floor drain or at least 24" off of the floor pointing down. It that think kicks open to release hot water pressure it would scald anyone standing near it.
 
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Old 04-21-03, 05:03 PM
sledgmb
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i'm not sure i understand...

1) got 1 cold water pipe going into the water heater
2) got 1 hot water pipe going out of the water heater
3) got 1 drain valve/pipe that runs all the way from the water heater to outside???

not sure what you mean by "terminates outside, near a floor drain." do you mean the drain pipe running from the water heater should run to outside - about 2 feet from the ground and pointing down. can out help me picture this?
 
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Old 04-21-03, 05:12 PM
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one cold pipe coming to the tank.

one hot pipe leading away from the tank.

one 3/4" diameter drain pipe (copper or CPVC) that is connected to the emergency temperature and pressure relief valve (Plumbers call this the "T & P"). The drain pipe screwed into the outlet of the t&P should drain downhill continuously away from the tank.

The drain should go to ONE of the these three places

1) outside. If the T&P opens up water will come out of it. Less mess outside. and yes near the ground will lessen the chance of hot water hurting some one.

2) near a floor drain. Again to minimise flood damage if the T&P needs to drain off water.

OR

3) near the floor so if it does open up, anyone standing next to the heater will not be splashed with 140 deg water.

In lots of houses you can't run it outside because you are below grade or you can't run it to a floor drain because you dont have one. If this is the case just put the tube near the floor.
 
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Old 04-21-03, 05:18 PM
sledgmb
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i guess that's where i'm getting confused. you say "near the floor". if anything comes out of it don't you have a huge mess on the floor? what volume of excess can you expect to come out of this area on a daily/weekly basis? is it just in case of emergencies and in 99% of the time nothing comes out?

sorry for the newbie questions...still a few weeks away from even purchasing the water heater. i'm sure it'll include instructions but i'm trying to get a leg up on the process.
 
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Old 04-21-03, 05:20 PM
sledgmb
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i should add that this is going in a small deer camp cabin. i'm going to be installing the water heater in the loft above the bathroom...
 
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Old 04-21-03, 05:41 PM
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yes it will make a mess if it opens up, that is why my first two options are preferable. It is very rare for there to be massive discharge of water but occassionally the T&P will drip slightly causing a puddle.

most heaters come with the t&p included.
 
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Old 04-21-03, 05:55 PM
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Well, I would almost 100% agree... You don't have to run it downhill to the outside since it is pressurized, but definitely get it to the outside and get it within 6" of the ground.... The only time I am allowed to run it inside to the floor is if it is in a location where it would not cause damage if it went off... Most of the time, it should not let out much water at all... Some water heaters go a whole lifetime without ever opening the t&p, especially if you are inclined to leave the temp turned down to a reasonable level... The one thing you DO NOT want to do is to plug the line... It must be run somewhere safe... And the only other line you might ever hear in reference to a heater is if the heater is in a location where a tank leak might ruin stuff, it may have to be put in a pan, and the pan will have an individual drain that has to go outside... I don't believe you will need on in your case...
 
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Old 04-21-03, 06:04 PM
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would it be alright to just simply run a pipe from the t&p straight down through the wall, through the floor, pointing straight down towards the ground? the cabin is built using a post/beam foundation - so it's a raised foundation. if it is underneath the floor (on the outside of the cabin) pointing straight down, does it have to be 6" from the ground? what is the reason for it being 6" from the ground? is there some kind of bug shield i can put on the end of this pipe to keep bugs/mice from climbing up into it?
 
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Old 04-21-03, 06:32 PM
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Well, the idea is just to get it close enough that if it ever went off it would not scald anyone... If you are over a crawlspace, you can just drill a hole into the crawlspace and terminate it there... Otherwise just take it outside and get it turned down... Don't worry about how close to the ground, but make SURE it is not so low that I would ever get clogged by dirt, and not so high that a wandering child or pet might be sitting under it when it blows off...
 
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Old 04-21-03, 06:37 PM
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Sure plenty of people run it through the floor to put it outside. Bugs wont be able to get past the t&P valve. No screen or other obstruction should be on the end. terminate it between 6" and 24" from the ground. High enough to stay out of the dirt, low enough not to spray anyone.

Ragnar are you sure that you can run them uphill? I thought that they would potentially rust shut when submerged on both sides.
 
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Old 04-21-03, 07:04 PM
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Well, as always, codes in different areas can be checked, but around here they are often run uphill... There is a stipulation though... Since a t&p valve is designed to hold water in one direction, it will many times leak if it blows out water and it sits against the wrong side of the valve... It will drip out from under the trip level handle... So if I have to run one uphill first, I have to cut in a tee that allows for draining the line down... That way, if a homeowner ever sees it leaking they can put a bucket under the drain valve and empty the line...

I prefer to always run down of course... One, because I don't like the extra work and expense of the tee and drain valve, and two, because I don't think the average homeowner would know what to do with the drain even if they had it there...
 
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Old 04-22-03, 08:59 AM
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I checked the UPC and I couldn't find it addressed directly. It does say that they should not be trapped, would the fact that it is full of water make it a defacto trap?
 
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Old 04-22-03, 04:22 PM
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Well, I am all about being funtional more than being code, as I think it is far more important... International Plumbing Code says that there should be no trapped sections, and that you have to have a visible airgap in the room with the heater... AND you have to have an electrical disconnect... But I also know that you cannot always get a relief line out of a building in an effective manner without going UP first... and if it isn't practical, an inspector can approve work that otherwise wouldn't be code... Also, it is routinely done here and will pass inspection every time unless it is deemed as unnecessary... I personally dislike code and wouldn't even own a codebook if it weren't for inspectors... ...
 
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