I have a rheem 50 gallon water heater i want to use for domestic water in my shop. It's has a hot water pipe coming out the top, but no cold water pipe coming out the top. My question is, can I bring cold water into it from the bottom tap on the tank? Like what's in the picture.
Domestic water heater
- Thread starter Bangon61
- Start date
Stuart in MN
Well-known member
I've never seen a water heater that doesn't have a cold water in connection on the top, that seem pretty unusual. If it's a recent model Rheem must have an installation manual available on their website that will show how it's supposed to be hooked up.
Well here it is.
Attachments
Firebrick43
Well-known member
Look up the installation manual for the WH. I imagine that is how they want it plumbed but you will know for sure if its in the manual
tinmanwpk
Well-known member
This one belongs in the WTF forum.
pvanderlugt
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- Nov 14, 2010
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- 334
Not sure about the 12-3 powering a 50 gallon heater either
nadogail
Well-known member
I don’t think that the Water Heater is intended to operating with out a Cold Water input.
paulsomlo
Well-known member
Sure - when the cold inlet is on top, it's guided down to the bottom by a dip tube anyway, so as not to dilute the hot water at the top of the tank. I'm guessing you rescued this from somewhere, and it appears that they used the bottom inlet. I would think that if you pried off the plastic cap on top, you might find a threaded plug in the cold inlet.
micromind
Well-known member
Some of the older water heaters I've replaced are fed at the bottom and the hot outlet is at the top.
As noted above, it the heater is fed at the top, there's a dip tube in the cold side that takes the cold water to the bottom.
As noted above, it the heater is fed at the top, there's a dip tube in the cold side that takes the cold water to the bottom.
Codyboy
Well-known member
Weird. Never seen that before.
But it's stamped "cold" on the top of the tank.
Remove that cap and install a dielectric ****** in it or feed it from the bottom.
But it's stamped "cold" on the top of the tank.
Remove that cap and install a dielectric ****** in it or feed it from the bottom.
It could have been used as a storage tank.
Seeing the plumbing at the bottom, i would assume it was set up to flow cold water from bottom and heat will rise to the top.
I would put it back to the correct set up, pulling the plastic cap on top where the cold water inlet is and installing your pipe there.
That setup will still fill and heat, but it bypasses the dip tube design. Normally, cold water enters through the top and a dip tube carries it to the bottom, so hot water rises and exits at the top. feeding into the drain, the cold water is just mixing at the very bottom. It can work, but it’s not ideal plumbing practice. it can shorten the effective hot water draw and sometimes create turbulence/sediment issues.
Seeing the plumbing at the bottom, i would assume it was set up to flow cold water from bottom and heat will rise to the top.
I would put it back to the correct set up, pulling the plastic cap on top where the cold water inlet is and installing your pipe there.
That setup will still fill and heat, but it bypasses the dip tube design. Normally, cold water enters through the top and a dip tube carries it to the bottom, so hot water rises and exits at the top. feeding into the drain, the cold water is just mixing at the very bottom. It can work, but it’s not ideal plumbing practice. it can shorten the effective hot water draw and sometimes create turbulence/sediment issues.
larry4406
Well-known member
Our Rheem hybrid heat pump water heater has the cold inlet at the bottom.
Hot is on the side near top, just below the refrigeration unit.
Hot is on the side near top, just below the refrigeration unit.
Mine was a Bradford-White with what they called 'hydrojet' (and preferred bottom connection). It was about inducing turbulence, to counteract sediment build up.
crazylunker
Well-known member
looks like they may have been using that tank for some kind of closed system heat source, whatever you do make sure t get rid of those galvanized fittings for domestic water
rlitman
Well-known member
I said the same thing the first time I installed one. That was almost 20 years ago, and it was an oil fired Bock with side vent.
I'd consider installing an extra anode under the plastic cap.
I used brass fittings and the steel ******* rotted off the tank instead.
At work, galvanized was the standard for eons, but now it's stainless. Getting threads to seal with SS is more tedious for sure.
rlitman
Well-known member
I'm a bit lost at what you're suggesting here. The galvanic difference between brass and stainless is almost nothing, but stainless in contact with non-stainless steel can easily start to actively corrode. If you're trying to protect your tank, stainless isn't any better than brass, and in many ways it's worse. Galvanized is of course the worst option.
No suggestion. Just sharing past experience, and current experience with stainless.
What material pipe fitting do you suggest for the first connection from the tank?
rlitman
Well-known member
Nowadays? I haven't installed a new water heater in years, but the next time I do and it has a "glass" lined steel tank, it'll likely be with heat trap *******. They're actually galvanized, but they have a plastic liner. My current water heater is a stainless tank, so I have a mix of brass and copper fittings on it.
Hobby_Man22
Well-known member
Mine is an 08 model and I believe it has both at the top. Can't remember the brand though. It's electric. Thing is a beast too. I recommend a 50 gallon minimum water heater. I can take a 25 minute shower before losing heat