Is Inlet Valve Required For "cold In" On Water Heater? - Plumbing - DIY Home Improvement | DIYChatroom

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Old 11-26-2010, 08:01 AM   #1
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Is inlet valve required for "cold in" on water heater?

I'm the guy whose water heater would not fill up. The brass gate valve is shot...Can I just pull the valve and connect the two ends of the PEX with a sharkbite coupling? Or is the valve required to be there? I have easy access to the main water line in if I need stop flow into house.

Also: The valve seems to be open halfway and the water pressure is low (showers escpecially). Could the bad valve be causing low water pressure?


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Old 11-26-2010, 08:23 AM   #2
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If the water heater springs a leak you would have to shut off the cold water as well (via the house main shutoff).

Not sure if code requires the shutoff at the water heater inlet, code probably does.

Nothing would prevent you from hooking up the line without the shutoff temporarily until you could get to Home Depot to buy a new one.

Ran into a situation (in an apartment) where two water heaters were connected in parallel for added hot water capacity. One sprung a leak and the cold shutoff was turned off pending heater replacement. They did not realize (and/or could do nothing about it) that leaking onto the floor was not stopped because full pressure coming back around from the hot side was still on the tank.

What they needed was shutoffs on both hot and cold of each heater. This can be dangerous because both hot and cold may not be shut off at the same time when the heater itself is still turned on as expansion of the water when heated could burst the tank.


The good conscientious technician or serviceperson will carry extra oils and lubricants in case the new pump did not come with oil or the oil was accidentally spilled, so the service call can be completed without an extra visit.

Last edited by AllanJ; 11-26-2010 at 08:28 AM.
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Old 11-26-2010, 09:31 AM   #3
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"This can be dangerous because both hot and cold may not be shut off at the same time when the heater itself is still turned on as expansion of the water when heated could burst the tank."
Wouldn't the PRV (assuming there is one) prevent bursting?
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Old 11-27-2010, 06:09 PM   #4
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I would never rely on the main to shut off completely I have ran into many houses where the main didn't shut completely off. I would put a valve in at the water heater, hey it's worth a couple bucks. You will be glad you did someday.
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Old 11-28-2010, 07:19 PM   #5
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Plumbing Code requires a shut off valve on the cold feed to the water heater. The valve is supposed to be located within 3' of the water heater.
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Old 11-28-2010, 08:02 PM   #6
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I'm pretty sure they make a shark bite shutoff valve ( I think I have seen them I am no plumber).
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Old 11-28-2010, 08:43 PM   #7
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code says that you need a full port, full open valve at the water heater. You can get a compression ball valve if your soldering skills are not that great
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Old 11-28-2010, 10:28 PM   #8
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I just replaced the shut off valve on the copper pipe carrying hot water out of my hot water heater with a shark bite shut off valve and it was a breeze to put on and works like a charm. There is a shut off valve for the cold water going into my water heater as well that works for now but if it ever develops a problem, I wouldn't hesitate to do the same to it. Here's a link to the thread:
Lost Hot water pressure
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Old 11-29-2010, 08:15 PM   #9
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how about a shut off valve with FMemale Pipe Threads nipple it into the heater and pex fitting going to the drop of cold water pex


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