Hacking the fridge

g

out

It's too late. With the compressor running 24/7 for several weeks, it need s to be replaced soon. I am adding external digital defrost (Rpi+Thermo+SS R) to buy some time, but not the final solution.

-- reposting ---

I am about to submit my repair estimate to the owners (relatives). I think they will have a sticker shock; so, give them enough time to think about i t.

A defective pressure regulator is causing the compressor to run all the tim e, icing up the pipe and evaporator coil, raising temperature to over 10 de grees. The cheapest hack is a Raspberry Pi, with temperature probe and sol id state relay, without breaking the refrigant seal. Otherwise, $500 just to recharge the refrigant.

  1. Rpi
  2. 0 Rpi + PR
  3. 00 Rpi + PR + CR
  4. 00 Rpi + PR + CR + CC
  5. 00 Rpi + PR + CR + CC + EC
  6. 000 New fridge

Rpi: Raspberry Pi controller PR: Pressure Regulator CR: Compressor CC: Condensor Coil EC: Evapulator Coil

Pick a number.

Reply to
edward.ming.lee
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Yes, lots of less-than-competent guys in refrigeration out there.

Well, if you take the $19.95 online course, you can get your own EPA green card. The right card (there are several different versions) allows you to buy the restricted refrigerants. But, you need to have the proper equipment to recover the refrigerant in the system. To recharge it, you just need a can of refrigerant and a gauge manifold set.

Jon

Reply to
Jon Elson

If the evaporator is shot, that can be replaced by any commercial refrigeration contractor. It is probably a pretty common repair to a walk- in box. The Tecumseh compressor can probably handle several years of 24/7 operation, as long as it doesn't run dry of lube oil or get full of water.

Jon

Reply to
Jon Elson

snipped-for-privacy@gmail.com wrote on 10/2/2017 5:43 AM:

I remember you now. You have problems with relatively simple solutions and make them much more complex than they need to be.

The rPi is a bandaid. It won't fix the problem with the fridge and if the thing is running too much, it will *still* run all the time eating expensive electrons.

I suggest you get a repair guy to find the *actual* problem with the system. They charge something for showing up and then by the hour for their time which should be no more than $200 total for an hour or two of diagnostic.

--
Rick C 

Viewed the eclipse at Wintercrest Farms, 
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Reply to
rickman

hink they will have a sticker shock; so, give them enough time to think abo ut it.

time, icing up the pipe and evaporator coil, raising temperature to over 1

0 degrees. The cheapest hack is a Raspberry Pi, with temperature probe and solid state relay, without breaking the refrigant seal. Otherwise, $500 j ust to recharge the refrigant.

nd

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ive

Perhaps RPi is overkill, but i need a programmable thermostat/timer that ca n handle 50A anyway.

Reply to
edward.ming.lee

And some knowledge.

Reply to
tom

Perhaps RPi is overkill, but i need a programmable thermostat/timer that can handle 50A anyway.

++++++++++++++++++++++++

No, you don't. You need someone qualified to work on commercial refrigeration.

Reply to
tom

Yes, i need someone competent to work on it, but i also want something to monitor it externally without hooking into the pressure system.

Reply to
edward.ming.lee

No, it's not overkill, rather overly stupid. Fix the damned thing and do it so it *can* be fixed. You've found a (toy) hammer, so everything in the world is a toy (nail) for you to play with. Just don't!

Reply to
krw

I think they will have a sticker shock; so, give them enough time to think about it.

the time, icing up the pipe and evaporator coil, raising temperature to ove r 10 degrees. The cheapest hack is a Raspberry Pi, with temperature probe and solid state relay, without breaking the refrigant seal. Otherwise, $50

0 just to recharge the refrigant.

s and

the

ensive

can handle 50A anyway.

Yes, it will be fixed. But it will happen again and probably did before. There is an older regulator and compressor next to it. We just want to be able to deal with it when that happen again, at least to buy some time wait ing for the repair.

Reply to
edward.ming.lee

Buy something standard. Any kludge you add will forever be a PITA, if not worse.

Reply to
krw

. I think they will have a sticker shock; so, give them enough time to thi nk about it.

ll the time, icing up the pipe and evaporator coil, raising temperature to over 10 degrees. The cheapest hack is a Raspberry Pi, with temperature pro be and solid state relay, without breaking the refrigant seal. Otherwise, $500 just to recharge the refrigant.

ions and

if the

expensive

hat can handle 50A anyway.

. There is an older regulator and compressor next to it. We just want to be able to deal with it when that happen again, at least to buy some time w aiting for the repair.

Raspberry Pi, USB thermometer and Solid State Relay. Just a couple of wire s. Nothing non-standard. If the system is working properly, the RPi shoul d only monitor it. It needs to pull the plug (via SSR) only if it's screwe d up like now.

Reply to
edward.ming.lee

And when you're not there, what does the HVAC guy do? Just say "NO" to non-standard electrical and plumbing systems.

Reply to
krw

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es). I think they will have a sticker shock; so, give them enough time to think about it.

n all the time, icing up the pipe and evaporator coil, raising temperature to over 10 degrees. The cheapest hack is a Raspberry Pi, with temperature probe and solid state relay, without breaking the refrigant seal. Otherwis e, $500 just to recharge the refrigant.

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ore. There is an older regulator and compressor next to it. We just want to be able to deal with it when that happen again, at least to buy some tim e waiting for the repair.

ires. Nothing non-standard. If the system is working properly, the RPi sh ould only monitor it. It needs to pull the plug (via SSR) only if it's scr ewed up like now.

Flip on the by-pass switch to fix the main system. Perhaps watch a video b efore working on the system. We want dual compressors and a vacuum pump to empty out either high and low side refrigerant. He should be able to swap out either compressor without pumping out the main system refrigerant.

Reply to
edward.ming.lee

Yes, it all sounds so simple to an armature.

Reply to
krw

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tives). I think they will have a sticker shock; so, give them enough time to think about it.

run all the time, icing up the pipe and evaporator coil, raising temperatu re to over 10 degrees. The cheapest hack is a Raspberry Pi, with temperatu re probe and solid state relay, without breaking the refrigant seal. Other wise, $500 just to recharge the refrigant.

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before. There is an older regulator and compressor next to it. We just wa nt to be able to deal with it when that happen again, at least to buy some time waiting for the repair.

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f wires. Nothing non-standard. If the system is working properly, the RPi should only monitor it. It needs to pull the plug (via SSR) only if it's screwed up like now.

o before working on the system. We want dual compressors and a vacuum pump to empty out either high and low side refrigerant. He should be able to s wap out either compressor without pumping out the main system refrigerant.

Why? That's exactly what they have to do to purge and refill the system. We just have it there permanently instead of them hooking and unhooking eve rytime. If they can't even understand that, they are not qualified to work on it anyway.

Reply to
edward.ming.lee

Tell me about all the problems you have servicing this thing for the next ten years (twenty would be more interesting). It's a loser.

Reply to
krw

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to run all the time, icing up the pipe and evaporator coil, raising temper ature to over 10 degrees. The cheapest hack is a Raspberry Pi, with temper ature probe and solid state relay, without breaking the refrigant seal. Ot herwise, $500 just to recharge the refrigant.

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e of wires. Nothing non-standard. If the system is working properly, the RPi should only monitor it. It needs to pull the plug (via SSR) only if it 's screwed up like now.

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ideo before working on the system. We want dual compressors and a vacuum p ump to empty out either high and low side refrigerant. He should be able t o swap out either compressor without pumping out the main system refrigeran t.

. We just have it there permanently instead of them hooking and unhooking everytime. If they can't even understand that, they are not qualified to w ork on it anyway.

Just because we want a hot backup compressor? We can always switch off (wi th valves) one or the other. We just want to do it without breaking the pr essure lines.

Reply to
edward.ming.lee

No, because you're creating an unreliable kludge that can't be maintained. Do it right or go home.

Reply to
krw

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(relatives). I think they will have a sticker shock; so, give them enough time to think about it.

sor to run all the time, icing up the pipe and evaporator coil, raising tem perature to over 10 degrees. The cheapest hack is a Raspberry Pi, with tem perature probe and solid state relay, without breaking the refrigant seal. Otherwise, $500 just to recharge the refrigant.

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y did before. There is an older regulator and compressor next to it. We j ust want to be able to deal with it when that happen again, at least to buy some time waiting for the repair.

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uple of wires. Nothing non-standard. If the system is working properly, t he RPi should only monitor it. It needs to pull the plug (via SSR) only if it's screwed up like now.

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a video before working on the system. We want dual compressors and a vacuu m pump to empty out either high and low side refrigerant. He should be abl e to swap out either compressor without pumping out the main system refrige rant.

tem. We just have it there permanently instead of them hooking and unhooki ng everytime. If they can't even understand that, they are not qualified t o work on it anyway.

(with valves) one or the other. We just want to do it without breaking the pressure lines.

It's already difficult to maintain the way it is. The pressure regulator i s either non-functional or disabled. It's been running on low refrigerant

24/7 for some time. I guess it's defrosted by regular power outage. Addin g refrigerant without solving the real problem made it worst.

Without controls, overnight temperature drop from 2C to -3C. Adding a 25A timer ($13, 2 days from Amazon) fixed the range from 2C to 0C. But even 6 cycles of 75%-on, 25%-off has +/2 2C error (4C to 0C). I still think it's better to have 2 compressors (and coils) alternating.

Reply to
edward.ming.lee

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