Water heater mystery

[jay1028]

Water heater is not making hot water, just barely warm. It is a solar sysyem 80 gal tank with just a top element of 2500watts@ 240v. Tank is 14 years old and mostly runs off one 8x10 solar panel on the roof. We have had 5 days of no sun and expecting the electric element to take on the job. But it is not. Measured 237v at the element when on and 13.8A measured with a clamp on ac ammeter. Figured the element might be bad somehow Eventhough the readings say otherwise.. Replaced it with a 3500w 240v. Still the same issue. After 6 hours, just warm water. I am at a loss. Shouldn't there be hot water after 6 hours of on time.

 

[RS]

Yes there should be hot water! That's a strange one! Thermostat? But if it's drawing current it should be heating. Could it be possible the dip tube is corroded off and the cold water is taking a shortcut to the outlet? Be sure to let us know what you find.

 

[jay1028]

Did some temperature measurements this evening. The metal exposed section of the tank is 83deg. The terminals on the element 85deg. Now here is the kicker. Pointed thermometer at black plastic thermostat housing and it read 96deg. I don't get it. Going to replace it tomorrow AM.

 

[jay1028]

Changed out the thermostat. Same thing, no difference. Seems that the temperature cutout atea is normally hotter than the thermostat area. It is taking 90 mins to raise the temperature 12deg. So starting at 70deg and going to 120deg,, it is going to take about 6 hours before the thermostat kicks on. Much longer than I would have imagined. When the sun is out, the tank gets to 130deg in just 6 hours.

 

[Jeff Handy]

Solution, only take a shower on sunny afternoons, haha.

 

[jay1028]

Got some latest info for you fellas. I am trying anything to see what effects a change. I turn off the incoming cold water to the tank. There is a ball valve at the input and I closed it. In less than a minute, you can hear what sounds like rapid boiling in the tank. When I open the valve to let in cold water, it sounds like water in coming into the tank and the boiling stops and goes back to its normal sizzling sound when the element is on.
The tank temp is 88 degrees and the hot water outlet is at 80deg. I open a hot water fawcet in the bathroom, the hot water outlet rises to 82 degrees and no more. If hot water was dissappearing out the hot water outlet dues to some kind of leak in the slab, wouldn't the output pipe be hotter than 80deg? I can't check to see if water is running due to the water meter is digital and not analog meter.

What does this mean?

 

[jay1028]

Attached is a photo of the solar water heater.

 

[Jeff Handy]

Does the loop up to the roof automatically get isolated when the sun is not shining?
I would think that both input and output should close with valves, and of course the transfer pump would turn off also.
Just a hunch because I have never dealt with solar water heat.

Otherwise, you might be pushing water through the solar collector, which now becomes a radiator giving away the heat from the hot water.
Or at the least, heat would be rising up there if the solar loop did not get isolated when not making solar heat.

Also, that is a big tank, and I think a normal 50 gallon heater would have a 4500 watt element.
And your tank is 80 gallons.
Not counting the extra volume in the solar loop.
So your 3500 watt element is working pretty hard to keep up.

Once again, just some ideas, I don’t have any experience with a solar/electric type of system.

 

[Diehard]

Where's that black plastic thermostat housing located?

Someone above questioned the dip tube.
Are you sure the dip tube brings the cold water to the bottom of the tank?

 

[jay1028]

@Diehard, Thermostat is located at top section and is the type for a single element. Don't know if dip tube is intact. Since it is an expensive solar tank, I would expect it to be made better than a $400 tank. Are there metal dip tube or are they always plastic?

@Jeff Handy, I was thinking like you and I have isolated the panel on the roof. If youn look at the phot, there are two green handles pointing downward. They cut off the water connection to the roof panel. In the up position, the panel is in the loop with the tank.

 

[jay1028]

Another photo attached

 

[Jeff Handy]

I only see one handle lower down, which I assume is the incoming cold water shutoff.

Meanwhile, you probably need a pro with solar water heat experience to weigh in on this issue.

EDIT I see the shutoffs now, in your new pic.

 

[Jeff Handy]

Be careful if you leave those valves shut, make sure the circulator is off first.

And if the sun is shining, they should probably be open, at least partially, or I could see the pressure in the solar loop getting too high from thermal expansion.

 

[jay1028]

Thanks Jeff. The panel is drained. This situation really has nothing to do with solar. It is a basic one element water heater with the roof collector out of the cjrcuit.

I just did a temperature measurement again. The inlet is 69deg and outlet is same temp as tank, 110deg. Should the outlet pipe be at the same temp as the tank?

 

[jay1028]

I have some news and it is bad. My wife is hearing water slowly running in the bathroom wall. I turn the inlet cold water off to the water heater. Water sound stops. I pried up the cover to the water meter in the ground outside. It is digital, but when you open the cover on the meter face, it powers up and you can see the last two digits counting . Turning off the water to the tank and it stops. We can't see water evidence anywhere, but is hot water related because when I turn on the hot water fawcr in the bathroom, I have warm water at 89deb, same as hot water tank.

Is there a specialty person/plumber that I need to get involved in this? I have turned off the cold water inlet to the tank until we need to shower. I wish I saw water coming out somehere to give us a sign.

 

[frodo]

I have some news and it is bad. My wife is hearing water slowly running in the bathroom wall. I turn the inlet cold water off to the water heater. Water sound stops. I pried up the cover to the water meter in the ground outside. It is digital, but when you open the cover on the meter face, it powers up and you can see the last two digits counting . Turning off the water to the tank and it stops. We can't see water evidence anywhere, but is hot water related because when I turn on the hot water fawcr in the bathroom, I have warm water at 89deb, same as hot water tank.

Is there a specialty person/plumber that I need to get involved in this? I have turned off the cold water inlet to the tank until we need to shower. I wish I saw water coming out somehere to give us a sign.

go look at the water heater, it has a brass valve on the top or the side with a pipe connected to it
that pipe either is piped outside or to a floor drain
find it, and see if the water you are hearing is coming from that

YOURS, is right there in the middle of those 4 pipes on top of the heater

 

[frodo]

Have you verified that you are getting 22o to the heater?
have you verified that you are getting 220 to each of the elements?

 

[jay1028]

237v is at the one element. Verified that no water is coming out of the relief valve. I faintly hear water in a pipe, not spraying or dripping, just running in the bathroom wall. House is 14 yrs old and all co0pper. I watched it being built. wish I had taken plumbing photos now.

One other thing: got almost instant hot water at the bathroom fawcet. It used to take 2 minsutes to get hot water before.

 

[frodo]

sounds like you got a leak
sounds like it might be at the sink
is your house copper under the slab?
manifolds behind fixtures in the wall?

 

[Jeff Handy]

Agree, hot water line leak.

It would likely have to be in or under the slab, otherwise wouldn’t you be seeing flooding somewhere in the house?

Call a pro, that constant leak is costing big money heating water being dumped under your slab.

And that leaking water could eventually undermine the support of the slab.