HW tank noise

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rankjo

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Joined
Mar 3, 2005
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337
Hi, the HW tank has suddenly started to make a buzzing whiny noise.
The noise is only there when the HW is running. It is on 110volt. There are no leaks and the pressure is normal.
I can feel a slight but palpable vibration in the "ho****er out" pipe at the back of the tank, and it is much much less in the "coldwater in" pipe, and at the front of the tank. When I increase the flow in the HW pipe by opening the drain valve, or decrease the flow using another valve, the buzzing vibration changes in pitch(though to my suprise the change in pitch is the same whether flow is greater or less), and if I open the drain valve all the way so the flow is really fast, then the noise goes away.
I tried opening the pressure release lever at the top of the tank to see if there was air in it, but there wasn't.

Any ideas?
Rankjo
 
There is supposed to be air in the top of the tank.  Consult your manual for proper draining and refilling procedure. In short, drain the tank, then refill with the pressure valve closed... DO NOT open it at any time.

carson
 
Our hot water tanks started making the same noise after we had it replaced about 2 years ago.  Not every time we run the hot water, but often.  It appears to be harmless so we just ignore it.  As long as there is no evidence of leaks, I wouldn't worry about it.

As Carson says, there should be an air pocket in the tank to allow for expansion, but I don't think that's related to the noise.  It isn't in our case.
 
I'm not sure about the air bubble being necessary. When you fill a HW tank you fill it with the expansion valve open till water comes out. With regard to leaving room for heat expansion, that's what the expansion valve is for.
I have been asking around, and it appears that there is a check valve on the back of the tank which can create noise. It is not clear to me how necessary it is to fix this, and it sure is difficult to see the back of the tank unless you are 6ft 6 and weigh 100lbs.
I plan to leave it till I get home and can set up to gain access.
Rankjo
 
Hi Rankjo, here is a little info for you on the subject matter.

An excerpt from the article in the link shown below:

The water heater is designed to trap a pocket of air above the water level in the tank. This air pocket compresses as the water is heated. The air pocket can eventually be absorbed by the motion of the vehicle and should be restored from time to time.


Check out this link

carson FL
 
Rankjo,

In 11 years of filling hot water tanks at a dealership I have never seen anyone leave the pressure relief valve open. You fill the tank with the valve closed. Then open a hot water faucet and let it run until all the air is purged from the lines and you have water flowing. Now you can turn on the heater. Doing that will leave an air bubble at the top of the tank.
 
Jim and Carson, I stand corrected.
I have been working under the impression that air comes out of solution in the HW tank and keeps the air pocket alive.
I'll try your system and report.
Rankjo
 
rankjo said:
Jim and Carson, I stand corrected.
I have been working under the impression that air comes out of solution in the HW tank and keeps the air pocket alive.
I'll try your system and report.
Rankjo
Click to expand...

It should work fine. :) There will be quite a bit of air that does come out. I wait until the water stops flowing and then open the faucet. Once water flows I know for sure I can turn the heater on without fear of doing any damage. Also I usually open the faucet closest to the tank so the air starts coming out faster as it doesn' have to travel as far.

 
BTW, I made a "re-circulator" for my hot water system. I have a second pump and a third line to bring hot water to the point of use. The line dumps back to the hot water tank. When the water at the point of use is hot enough a light is energized. It doesn't really save propane, but saves water when dry camping, and gets the hot water to the faucet faster than just running the water down the drain. I first had it set-up to run by holding a button, but now I have a holding circuit (relay) that runs the pump until the water at the faucet is warm. I am a bit cheap so the temperature sensor is at the pump not each point of use.

 
Regularguy.....could you give a bit more info, maybe a diagram of what you did to do the constant hot water system. sounds like a great idea.
Gregg
 
I don't have access to my scanner, but I will put the design in text as best as I can.
My hw heater is in the front of the rig, the kitchen sink is in the rear, the bathroom is middle on the opposite side. I placed a tee just below the kitchen sink, ran a line back to where the original main line tee'd to the bathroom, removed that original tee (replaced with coupler) and placed a coupler to connect the new (extra) line to the branch for the bathroom. At the bathroom I placed a tee in the line just below the sink (furthest in bathroom) then ran a line back the the vicinity of the hw tank. There I placed another sureflow pump and ran a line to the cold water fill for the hw heater. I utilized the original pump to act as a check valve on the supply side of the cold water fill line to prevent the new pump from trying to push water back into the fresh water tank (or city line). If the original pump is not in a convenient location, then a check valve is in order. I placed momentary switches at the two locations (kitchen and bath sinks) and utilized a relay to make a holding circuit with a temperature switch in-line just after the bathroom tee. The temp switch is set for 100 degees F (my hw heater is factory set for 120). I then ran wires to the remote switch locations and tapped the switched wire to the new pump so that as the pump is running a light is lit at the remote location(s). Later I placed temp sensors at each location and used an indicator light to show if the water at the location is warm (in the case there is already hw there). The temp switch I used has a normally open and a normally closed switch. I used the normally closed switch to send power to the temp sensor and indicator light and the normally open to send power to the (pump running) indicator. the temp indicator light stays lit as long as the water is warm enough, but it does not use much power (led). So the sequence of operation is as follows: pushing the momentary button causes a "holding circuit" to energize through the normally open contact of the temperature sensor. The pump is energized and pulls hw through the original line then the added line until it reaches the temp switch (and the set-point). The temp switch then opens which opens the "holding circuit" and the pump is de-energized. I hope I explained it clearly for you. A more elaborate design would incorporate solenoid valves so that the water would flow only to the point of use instead of throughout the whole system but the valves are expensive and the extra water that will have to be reheated is minimal in cost to the valves.
 
a holding circuit is as follows: Pushing the momentary switch energizes the coil of a relay. The normally open contacts of the relay (now closed) will send power to the device (pump etc) and back to the coil of the relay. The relay will now stay energized until something opens that circuit. The thing that opens the circuit in this case is the action of the contacts of the temperature switch (for the pump) when the water in the line reaches the set-point of the temperature switch, which causes the switch to "switch" to the normally open contacts. Note: most temp switches with both no and nc contacts will operate as such: the no contacts will close on a rise in temp and the nc contacts will close on a drop in temp.
 
Thankyou Regualarguy, this is something that I am going to try to add to mine. Thanks again Gregg
 
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