Entropy

Relax in southern comfort on the east bank of the Mississippi. You're just around the corner from Beale Street and Sun Records. Watch the ducks, throw back a few and tell us what's on your mind.
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JR.
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Re: Entropy

Post by JR. »

terkio wrote: Mon Dec 21, 2020 7:10 pm
The hang tag on the relief valve says to check them every two to four years. It sounds like they expect you to remove it to inspect for evidence of overheating.
Isn't it simply operating the valve ( open then close ) without removal.
I don't feel lucky... what if I test it and it doesn't stop leaking?

The tag said to look for overheating (deformation) of the plastic part sticking inside the tank.

This to make sure it is not stuck.
Acid waters make corrosion. Alkaline waters make limestone scale. Choose your doom.
I choose neither
Some leak at the valve is normal,
In my several decades I never saw a puddle from the T&P valve having a nocturnal emission.
it is there to take care of expanding variations while temperature goes up, to make sure it will leak instead of the heater tank busting.
Yes, understood, but i don't think my tank was in any risk of rupture. But it is in even less risk today since I turned down both thermostats about 10 degrees cooler.

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terkio
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Re: Entropy

Post by terkio »

Isn't it simply operating the valve ( open then close ) without removal.

I don't feel lucky... what if I test it and it doesn't stop leaking?
So do I.
Despite of service manuals and internet advices, I rather not touch it, in case it is so badly stuck from scale, it won't go back closed.

At my place, heathers die choke full of limestone scale anyway....Then is time for maintenance.
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JR.
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Re: Entropy

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terkio wrote: Tue Dec 22, 2020 5:46 am
Isn't it simply operating the valve ( open then close ) without removal.

I don't feel lucky... what if I test it and it doesn't stop leaking?
So do I.
Despite of service manuals and internet advices, I rather not touch it, in case it is so badly stuck from scale, it won't go back closed.

At my place, heathers die choke full of limestone scale anyway....Then is time for maintenance.
My typical local water heater failure mode is internal corrosion. I ignored the rusty colored hot water but when my old heater rusted through the heater element casing to the point that I was feeling electrical shocks from my shower water, it was time to pay attention.

I have come to the conclusion that the water heater manufacturers provide a sacrificial anode that is sized to last just long enough for the warranty. Further they make them all but impossible to replace. I decided to proactively check and replace my anode before it was consumed (within first two years). No luck, even using a long handle on my breaker bar. Then I upgraded to a compressed air impact wrench, still no luck breaking it loose. I even hired my local plumber to get it out, and he couldn't so it's not just because I am old and weak.

The heater is only 5 years old, but the T&P relief vale leaking is a nudge toward considering replacement.

A tankless hot water heater would be most efficient but requires more current than available from the existing drop to support a decent shower. I have seen modest flow heaters that can draw power from two 40A breakers, I suspect I could repurpose breakers from my in wall radiant heaters that are no longer in use, but still beyond DIY wiring for me.

I could get away with a smaller replacement tank/heater. They make as small as 19 gallon with only one heat element, that should work for me. But let's see how the replacement T&P valve works.

The old T&P valve is still damp/wet so it hasn't dried out yet. I just put a plastic cup under it to see if it is still leaking.

[update- it didn't take long for dripping water to accumulate in the plastic cup, now I am thinking perhaps it was neither a temperature or pressure event but just an old fashioned leak. still sux.... I rigged a spare washing machine discharge hose to capture the drip. /update]

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mediatechnology
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Re: Entropy

Post by mediatechnology »

I've found that when I tested the T&P relief valve they always started leaking so I decided not to ever do that.

I replaced my hot water heater 10 years ago when we remodeled.
I told myself I would replace it ever 10 years whether it needed it or not.
That was last October...
Now the problem is that they've gotten so much bigger and a 40 gallon may not fit.

Though they're inefficient I like having stored hot water.
Fortunately ours is gas and it will heat without power.
Living in the city I never realized what a luxury natural gas was.
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JR.
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Re: Entropy

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mediatechnology wrote: Tue Dec 22, 2020 2:28 pm I've found that when I tested the T&P relief valve they always started leaking so I decided not to ever do that.
apparently they can start leaking even without being tested. :roll:
I replaced my hot water heater 10 years ago when we remodeled.
I told myself I would replace it ever 10 years whether it needed it or not.
That was last October...
Now the problem is that they've gotten so much bigger and a 40 gallon may not fit.
physically bigger? More insulation perhaps. I am considering and even smaller 19 gallon heater if I replace. I have a 40 gallon now but living alone, probably more than I need.
Though they're inefficient I like having stored hot water.
Fortunately ours is gas and it will heat without power.
Living in the city I never realized what a luxury natural gas was.
Now that I expect the water I saw is from a dripping valve and not over-temp or over-pressure, I may ride this horse for more of the race after I replace the T&P valve.

I am even considering taking another run at the replacing the sacrificial anode. A compressed air impact wrench didn't get it done, but I may look at using a band/strap clamp around the body of the tank to prevent it from twisting and use a longer pipe on the breaker bar handle to amplify torque.

With reasonable attention to keeping a fresh anode in place, corrosion should not be an issue. I even have a powered anode that makes all kinds of benefit claims, that I haven't been able to use.

I really think the manufacturers go out of their way to make the anodes hard to remove. This isn't rocket science, but slick (dirty) business, to help them sell more replacement heaters.

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Re: Entropy

Post by mediatechnology »

Is this the one that had the leakage current?
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JR.
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Re: Entropy

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mediatechnology wrote: Tue Dec 22, 2020 4:45 pm Is this the one that had the leakage current?
this is my replacement heater, so only about 5 years old. This replaced the one that tried to kill me which was several decades old and making rusty hot water for years. I suspect with fresh sacrificial anodes that old one might still be working. But my idea of home maintenance is mainly fixing stuff after it fails.

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Re: Entropy

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I just emptied the water accumulating in the old washing machine discharge hose into a plastic container, so still dripping.

The replacement valve won't arrive for another week. I just ordered a band strap to try to prevent the heather tank from twisting for another attempt at removing the anode. The heater could out last me with a fresh anode.

====
not quite entropy but an overnight 2" rain storm took my buried pipe box drain grate and washed it away somewhere? I looked in the obvious places and couldn't find it. Replacement grate on order.

=====
Both of my very old TS-1 are misbehaving... I opened one up yesterday to trouble shoot and apparently I have one of the early prototypes so it doesn't agree with the schematic... I figured this out once (50 years ago) time to try again. In the last week I had two different people contact me for TS-1 repair advice...

Merry Christmas world/

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Re: Entropy

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For an update, water is still accumulating in the plastic jug attached to my pressure relief valve discharge hose. Still waiting for the replacement valve.

==

Today I decided to revisit my two broken TS-1.... The first one was hurting my head trying to figure out the fault. The circuit did not agree with the schematic because it was probably an early prototype. When I opened it up, I found a spare PCB rigged to the bottom, so this was part of refining the original design.

I figured out an omission(?) from the published schematic. The -V for the 13600 dual OTA is not connected to -15V as expected from data sheets but instead to a synthesized -2V supply I made with a simple resistor divider and pnp buffer. Peering back through 40 years of cobwebs I now remember why I did that. It was not trivial to make a voltage/current controlled oscillator not only operate over a 1000:1 range but be relatively stable. I determined that the power dissipation from changing the OTA current 1000:1 would result in chip temperature changes that diminished frequency stability. Dropping down the rails to +5V and -2V helped in that regard.

Despite figuring that out I still couldn't see why the sine wave frequency was so jumpy in the lower range. Since I had two broken TS-1s I decided to open up patient #2. This one had a pretty obvious fault... the frequency dB switch was not closing contact... with my VOM I measured no wiper action on any of the switch poles. An old school F2uEE switch, that I have used truckloads of over the years, but no new old stock in my back lab. I did find one on a bread board that I was able to unsolder.

That was easy, actually nothing is easy...I lifted one PCB trace but I was able to jumper the connection. Bingo, I got it working, and decided to rethink patient #1. Maybe the problem is the frequency pot? Good news it was a flaky pot, bad news I don't have a 10ka taper handy... I dropped in a 10kb and it started working but really fast at the LF end (duh). It looks like it stopped working after I put it together but not today's problem. I could try slugging a 100k pot that a few thousand of sitting around.

[update- I may not need to slug, the 100k will sag due to the circuit impedances, tomorrows project]

But now that I have a working TS-1 my bench is back up and happy.

JR
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Re: Entropy

Post by JR. »

success with the second TS-1... Something was loading down the -15v rail but when I removed the faceplate it cleared the sagging rail and started working again.

I dropped in a 100kb in place of the the 10ka... I didn't slug it so may revisit... This was clearly a preproduction prototype so doesn't even have the LF trimpot we added for production.

I will drop a note in the schematic here to clarify the connections around the frequency pot.

JR
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