questions about this small "utility" water heater

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Frank DuVal said:
If you feed it cold water, it is NOT supplemental, it is the hot water source for your kitchen sink and dishwasher.

If you have a new energy efficient dishwasher, that should be enough water to feed it, and the dishwasher will heat it the rest of the way depending on cycle you choose (regular, sanitize, etc). Might not have any hot water for hand washing items (pots/pans) at the same time. Only time will tell. That and how many people will be using it. The chart for reheat times in on the Bradford-White website. If you are in an area that always has 65-70 °F water then you are quicker than us in the winter with 40-45 ° water.

You might set that thermostat to any temperature you like, but if over 120°F, scalding is a real threat. I know, I grew up in a house that had 160 °F water. One of my earliest memories is getting burned by water.:eek:

Bradford-White go the voltage right, just not the wattage. Twice as slow to recover at 1500 W.
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Thanks, Frank. Yeah I guess maybe supplemental isn't the right term - but just in the sense I have a perfectly good 50gal unit that can handle the whole house, but choose to add the 10gal unit, figuring it'll definitely add convenience of quicker hot water, and hopefully be at least a break-even on efficiency (with savings from avoiding "stranded" hot water cancelling out the tank's standby losses).

I think the dishwasher uses only a couple of gallons at startup, so you've still got at least 5 minutes of handwashing out of a 1.8gpm faucet (with some cold water mixed in). I keep main unit at 120 degrees or so, but figure scalding is a much smaller risk in the kitchen (you're only exposing your hands, not your entire naked body); so maybe go with 140. And my incoming water is pretty close to 60 degrees.

But, if I'm all wrong, I feed the thing with hot water. That's the beauty of PEX (which I'm just discovering); I like it - it reminds me of wiring.
 
mgookin said:
The shipper did his job. It got to you. The supplier made a mistake. He needs to eat it and send you the product you ordered and have his carrier pick up the wrong one. I wouldn't go making modifications to listed equipment to help someone else mitigate their error.
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I cannot agree more with the above.
 
RustyShackleford said:
Yeah, it's supplemental. But I think I'll feed it with cold water. The main reason is to avoid long waits for hot water in the distant kitchen. But also to save the wastage of all the hot water that remains in those long pipes when you shut the faucet off. Feeding the satellite with the main hot system would defeat this. Won't be too hard to change if I change my mind because I'm running the tank dry in the kitchen a lot. But right now, I just like having one 3/4" cold line going to the kitchen.
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Larger pipe wastes more heat and takes longer to purge if you only have the remote water heater. If all you are supplying is a kitchen faucet a 1/2 inch pipe is probably even a little larger then needed.

As mentioned the reason to feed this with hot water is to have more instant hot water, but if in a situation where using a lot of hot water you will have hot water supplied and it will take a pretty long time before the tank would ever get cold. A 1500 watt element would even be somewhat overkill for the application then, but is the most common model to be found.

Hot water left in your pipes when done using the hot water is only waste heat in the summer months. In heating season it is some relief to your heating system load.

Just having that second water heater in your kitchen does add to the needed cooling load in your home also.
 
RustyShackleford said:
w the wiring should be attached. It's not the usual setup where there's a small access panel in the top, See the picture. There's a small hole just to the right of the access cover (for the thermostat and heating element). The hole looks like where a Romex clamp should be installed (you can even see where you can knock it out for a bigger size clamp). But there's no way to access the locknut for a clamp, other than by sticking your finger through from the access panel opening and trying to hold it tight enough to lock it in place by rotating the outside part of the clamp). Worse still, the threaded body of a clamp would stick in close enough to the metal plate (you can see behind the clamp through the hole) that there's hardly room for the wires to go left to the access area - even though I'm only using 12-2.
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If it were me, I would likely use a 90 degree connector with a lock nut, I would put the connector of the cable first, then remove the lock nut, slide the wires through the hole sideways towards the access and slide the lock nut over the wires at the same time. Might have to experiment a few times to pre-form the wires so that connector sits in correctly without jamming the wires against the sides. Once complete fish a finger in the space, standing on head as needed and get the lock nut threaded on. The wires hold the lock nut so the first ten times it slips off your finger it does not get lost. ;)
 
kwired said:
Larger pipe wastes more heat and takes longer to purge if you only have the remote water heater. If all you are supplying is a kitchen faucet a 1/2 inch pipe is probably even a little larger then needed.
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The 3/4 I'm running to kitchen area is cold, so no issue there. The only hot pipe, going from 10gal unit to main sink and a prep sink, is 1/2", 12ft total (plus what goes up into walls to stop valves). If I decide to feed 10gal with hot instead, I've still got a 1/2" hot pipe going to kitchen from when house was originally plumbed.

You're correct that if I end up feeding it with hot water, 3500watts is overkill. But, there's no downside to 3500. Longer lead-time on the heater, but no added cost. And I've already run 20amp service there. Plus, both water heaters are fed from a little subpanel with no neutral, so 120v unit is a non-starter.

Hot water left in your pipes when done using the hot water is only waste heat in the summer months. In heating season it is some relief to your heating system load.

Just having that second water heater in your kitchen does add to the needed cooling load in your home also.
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Right you are - because this is all in an encapsulated crawlspace. Simple calculation says the heat loss through the surface area of the tank is 20 watts (assuming R-8 tank insulation and 60 degree differential between ambient and hot water). So hardly a big deal either way. I guess I should try to calculate heat loss due to stranded hot water.
 
You may be able to fix the connector body interference inside the box by putting s second nut outside the box. You might then be able to tighten that nut rather than the inside one to secure the clamp.

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I am pretty sure this is the type of connector required.

BPFTNGC00002_77_TN_001.jpg


It installs from one side and there is no locknut to have to deal with.
 
K8MHZ said:
I am pretty sure this is the type of connector required.

BPFTNGC00002_77_TN_001.jpg


It installs from one side and there is no locknut to have to deal with.
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Does it work with flexible conduit?

99% of the time I would be running FMC from a disconnect to the water heater.
 
K8MHZ said:
I am pretty sure this is the type of connector required.

BPFTNGC00002_77_TN_001.jpg


It installs from one side and there is no locknut to have to deal with.
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I actually agree with you. I think this is the type connector the A-hole that designed the water heater expects you to use.

Now if I use metal flex I will probably end up useing a chase nipple and a rigid coupling and then a flex connector. Not the best solution in the world but have to get the wire in there some way.
 
mbrooke said:
But is it code? I know this is a grey area, but in my eyes NM is subject to physical damage.
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So is RMC if you hit it with a Caterpiller D9, or even just with a grinder with cut off wheel installed. How likely is NM to be subject to physical damage can vary greatly from one install to the next? I use flex partly because it just looks like a neater install.
 
kwired said:
So is RMC if you hit it with a Caterpiller D9, or even just with a grinder with cut off wheel installed. How likely is NM to be subject to physical damage can vary greatly from one install to the next? I use flex partly because it just looks like a neater install.
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Under a sink or in a closet; pots, pans, utensils, mops, tools, and who knows what else can damage it. There have been cases where landlords have filed insurance claims involving property damage only to be turned down under "hard-living" exceptions. Which basically means the legal system recognizes that people can be very uncaring toward a property and come real world there is plenty of evidence of that.


Not to detract, but just to back up my claim:




http://www.city-data.com/forum/renting/150817-trying-recover-tenants-damage.html

http://www.lawyers.com/ask-a-lawyer...wont-pay-they-say-its-hard-living-519423.html
 
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