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Bud, Plumber
Category: Plumbing
Satisfied Customers: 556
Experience:  22 Years Field Experience - 17 Years Business Ownership - Residential or Light Commercial
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Two hot water heaters. Shut one off and plumbed other to feed whole house.

Resolved Question:

1) Do I need to shut the input valve?
2) Do I need to drain tank?
3) What is risk if someone turns breaker on and their is not pull of hotwater from that tank.

THanks Bill
Submitted: 7 years ago.
Category: Plumbing
Expert:  Bud replied 7 years ago.

Hi Customer,

Thank you for asking your question on
I am Bud - Your personal online "Plumbing Consultant"

I need additional information before giving an accurate answer.

Could you explain your situation a bit more for me. Are they plumbed in series or parallel?


04/19/2009 1:40 PM

Together we can get to the root of your problem.


Please note: I will work with you and try to provide a satisfactory answer to your question, but it may require a few exchanges before we reach that satisfactory answer. I am here for you!!!

Customer: replied 7 years ago.
Let me try to answer. One serves part of the house the other serves the other part. Their are two valves, the first is about 5 inches from output of one of the WH, this is now closed, the second valve which was closed is now open which is along a hose about 10 inches above the output on each water heater. The second valve allows the 1st water heater to now supply the entire house.
Expert:  Bud replied 7 years ago.
Ok, I think I understand you situation. You have a common fed into the tanks, but the two did feed different parts of the house. Now the two different house feeds are tied together so that either of the heaters could feed the entire house. In that case I would turn off the electric, valve to the inlet and outlet, then drain the water heater that won't be used. The water would stagnate otherwise.

04/19/2009 1:48 PM

I hope the above information helps, if it does not please let me know.



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Customer: replied 7 years ago.

One point of clarity. There are two separate intakes. Based on your drain suggestion, I would say that needs to be shutoff. Is that correct? Also, how do I draing it and what happens if the electricity turns back on (don't ask but the breaker is outside so it is possible)


1) Do I shut off the independent intake?

2) How do I drain it?

3) Is there a risk if electricity comes back on?


Expert:  Bud replied 7 years ago.
  1. Yes
  2. Attach a garden hose to the drain valve near the bottom of the water heater and locate the other end of the hose lower than the drain valve. Open the valve and open the T&P relief valve to allow air into the tank.
  3. The only risk is, burning the upper element out.

04/19/2009 1:58 PM

I hope the above information helps, if it does not please let me know.



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Expert:  Bud replied 7 years ago.

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