Author Topic: How safe is it to use a SSR to control power to a spa? Or use a relay?  (Read 10229 times)

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Offline NiHaoMike

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Check if there's an existing control relay you can tap into. Other than that, a contactor controlled by a smart plug is one very easy way to automate large loads.
Cryptocurrency has taught me to love math and at the same time be baffled by it.

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Offline Gyro

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Sigh, don't they offer next day?

They do, but 2 day shipping is free.  I wonder what Digikey and Mouser would charge.  Don't they have a minimum order size?  I think they would charge more than $10 just for the shipping.

I sometimes wonder what the point is of spending my time to give someone technical advice, only to get dragged into this sort of crap.  :palm:

Buy it where you want.
« Last Edit: July 19, 2020, 08:41:37 pm by Gyro »
Best Regards, Chris
 
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Offline DougSpindlerTopic starter

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Check if there's an existing control relay you can tap into. Other than that, a contactor controlled by a smart plug is one very easy way to automate large loads.

I have and there is not one relay.  There are at least 3.  One for each of the two pumps and another for the heater.  The electronics have "settings memory" so if power is lost the settings are retained.  (My last tub the settings were lost.)

 

Offline DougSpindlerTopic starter

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Sigh, don't they offer next day?

They do, but 2 day shipping is free.  I wonder what Digikey and Mouser would charge.  Don't they have a minimum order size?  I think they would charge more than $10 just for the shipping.

I sometimes wonder what the point is of spending my time to give someone technical advice, only to get dragged into this sort of crap.  :palm:

Buy it where you want.

You are upset because I'm not buying from one of the two vendors you suggested?  My post was for advice on using an SSR vs a relay.  Did you even answer that question?   

 

Offline Gyro

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I'm not upset, just pissed off. My only point was that you should buy one with a genuine approval. I'm in the UK, I don't use either.... and yes I did - I said use a contactor not an SSR. Go back and read your own thread!
Best Regards, Chris
 

Offline Benta

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Gyro, you have my sympathy :)
A technical thread devolving into "where is it cheapest" and "I don't care if it's genuine" is kind of sad...

 
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Offline DougSpindlerTopic starter

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I'm not upset, just pissed off. My only point was that you should buy one with a genuine approval. I'm in the UK, I don't use either.... and yes I did - I said use a contactor not an SSR. Go back and read your own thread!

I am taking your advice and using a contactor.  Thank you very much.
 

Offline DougSpindlerTopic starter

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Gyro, you have my sympathy :)
A technical thread devolving into "where is it cheapest" is kind of sad...

No that's not true.  If I wanted cheaper I could have used Banggood.




 
 

Offline DougSpindlerTopic starter

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Thanks for all of the comments.  Decided to go with a $10 relay/contactor I found on Amazon.  Others have purchased it saying they have used them of air conditioners, compressor motors, electric hot water heaters etc.  Should be fine for my application.  What's the worst that would happen?  Heat up and the contacts remain closed/shorted?  Or burn out and remain open?  The GFCI is their to protect the people so no problem there.

I guess the worst thing that could happen is the relay overheats and someone causes a fire in a hot tub filled with water.  Fine with me, I have insurance.
 

Offline bdunham7

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How are fake Cisco products getting into the supply chain?  These are not just isolated incidents either.

Because people are willing to buy from less-reputable distributors to get a deal and those less-reputable distributors are willing to buy stuff out of the back of a stepvan in the middle of the night.

A 3.5 digit 4.5 digit 5 digit 5.5 digit 6.5 digit 7.5 digit DMM is good enough for most people.
 

Offline DougSpindlerTopic starter

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How are fake Cisco products getting into the supply chain?  These are not just isolated incidents either.

Because people are willing to buy from less-reputable distributors to get a deal and those less-reputable distributors are willing to buy stuff out of the back of a stepvan in the middle of the night.

That's the American way.  What made America Great and Proud.  I would not call buying something off of Amazon akin to buying stuff out of the back of a stepvan in the middle of the night.


 

Offline bdunham7

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That's the American way.  What made America Great and Proud.  I would not call buying something off of Amazon akin to buying stuff out of the back of a stepvan in the middle of the night.

If it is sold by Amazon directly, then it is likely not fake unless it is an item with inventory commingling.  Is this a Packard contactor?  Even less likely to be fake because nobody will bother to clone something already at the low end of the price range. 

However, buying a Cisco router from a third party seller on Amazon is indeed like midnight stepvan shopping.  Interestingly, many people like their 'deals' so much they willfully overlook the counterfeit issue, even when it is fairly obvious.
A 3.5 digit 4.5 digit 5 digit 5.5 digit 6.5 digit 7.5 digit DMM is good enough for most people.
 

Offline Benta

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I guess the worst thing that could happen is the relay overheats and someone causes a fire in a hot tub filled with water.  Fine with me, I have insurance.

In that case you don't. Read the fine print.
 
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Offline robca

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If you are in the USA you very likely might have a Platt close by, and you can get a reliable contactor from Platt (if they don't have it in store, they can get it delivered to the store free for you in a short time, usually)

I'm all for saving money and I buy routinely from dodgy Aliexpress/eBay sellers, but for things on mains and higher currents, I prefer to use trusted suppliers.
 
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Offline bob91343

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Don't overreact to my caution about insurance.  I have heard horror stories and think it's wise at least to add that concern to the equation.

These guys know how to play hard ball so make sure you know what you are doing.
 

Offline DougSpindlerTopic starter

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Don't overreact to my caution about insurance.  I have heard horror stories and think it's wise at least to add that concern to the equation.

These guys know how to play hard ball so make sure you know what you are doing.

I know exactly what I am doing.  I live in California where earthquake insurance is very expensive.  That's why I keep a gallon of gas on top of my natural gas hot water heater.  Should their ever be a large earthquake that would damage my house the fire insurance will cover it.



 

Offline cdev

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Check with your local building and health deparments that your hot tub is code compliant. Better safe than sorry.

In my experience, spas always had to be connected to a reliable mechanical timer switch with a maximum on time per turn of an hour or less (check local laws)  All this means is that you have to give it a twist every hour. (you have to be present and conscious)
The reason is that people have lost consciousness in spas and literally have been cooked alive.

Also, you are not supposed to bring alcohol into a hot tub and may be required to post a sign to that effect..

The temperature should not be allowed to get too hot. The CDC recommends 104°F (40°C) as the maximum temperature.

The need for a mechanical timer prevents it from just being left on. My knowlege may be old but in my experience, a mechanical timer tends to be the most reliable kind.

 (They are also useful for soldering equipment. Its easy to reset a timer and worth it for the peace of mind knowing your soldering iron or preheater cant be left on all day by mistake).
« Last Edit: July 20, 2020, 04:52:05 pm by cdev »
"What the large print giveth, the small print taketh away."
 

Offline james_s

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I would attack this from a different angle. The spa already has a system that controls power to the heater and pump(s). You can intercept the low voltage signals that control those, or you might look at upgrading the control, I'd expect there are models available that can be programmed to run during certain hours. Mine has an "eco mode" that only heats during the scheduled filter cycle and that can be programmed to run at a specific time and it's pushing up on 30 years old so nothing new there.
 

Online langwadt

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Don't overreact to my caution about insurance.  I have heard horror stories and think it's wise at least to add that concern to the equation.

These guys know how to play hard ball so make sure you know what you are doing.

I know exactly what I am doing.  I live in California where earthquake insurance is very expensive.  That's why I keep a gallon of gas on top of my natural gas hot water heater.  Should their ever be a large earthquake that would damage my house the fire insurance will cover it.

maybe, or the isurance will say the fire was caused by the earthquake and not covered.

Louis Rossmann has told several times about his business insurance refusing to covers loss from not having electricity,
because they didn't cover flooding and the missing electricity was caused by a flood at the powerstation
 

Offline DougSpindlerTopic starter

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Check with your local building and health deparments that your hot tub is code compliant. Better safe than sorry.

In my experience, spas always had to be connected to a reliable mechanical timer switch with a maximum on time per turn of an hour or less (check local laws)  All this means is that you have to give it a twist every hour. (you have to be present and conscious)
The reason is that people have lost consciousness in spas and literally have been cooked alive.

Also, you are not supposed to bring alcohol into a hot tub and may be required to post a sign to that effect..

The temperature should not be allowed to get too hot. The CDC recommends 104°F (40°C) as the maximum temperature.

The need for a mechanical timer prevents it from just being left on. My knowlege may be old but in my experience, a mechanical timer tends to be the most reliable kind.

 (They are also useful for soldering equipment. Its easy to reset a timer and worth it for the peace of mind knowing your soldering iron or preheater cant be left on all day by mistake).


Your information is old and out of date.  A mechanical timer will not work for this application.  The power companies in the US are changing how they charge for electricity.  The amount of money we pay for electricity changes 5 times today.  Prices will range from $0.12 kWhr to $0.54 depending on the time it is purchased.  Then on weekends the times change.

With a mechanical timer I would be really screwed when the power company shuts the power to the city during high winds.  I would have to reset the timer every time that happens.

While I appreciate your suggestion, it's not solving the problem. 





 

Offline DougSpindlerTopic starter

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Don't overreact to my caution about insurance.  I have heard horror stories and think it's wise at least to add that concern to the equation.

These guys know how to play hard ball so make sure you know what you are doing.

I know exactly what I am doing.  I live in California where earthquake insurance is very expensive.  That's why I keep a gallon of gas on top of my natural gas hot water heater.  Should their ever be a large earthquake that would damage my house the fire insurance will cover it.

maybe, or the isurance will say the fire was caused by the earthquake and not covered.

Louis Rossmann has told several times about his business insurance refusing to covers loss from not having electricity,
because they didn't cover flooding and the missing electricity was caused by a flood at the powerstation

California law is if the fire happens after the earthquake you are covered by fire insurance.  If the fire happens before the earthquake you are not covered.
 

Offline bdunham7

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California law is if the fire happens after the earthquake you are covered by fire insurance. If the fire happens before the earthquake you are not covered.

Really?  Can you tell me where I find that law?
A 3.5 digit 4.5 digit 5 digit 5.5 digit 6.5 digit 7.5 digit DMM is good enough for most people.
 

Offline DougSpindlerTopic starter

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I would attack this from a different angle. The spa already has a system that controls power to the heater and pump(s). You can intercept the low voltage signals that control those, or you might look at upgrading the control, I'd expect there are models available that can be programmed to run during certain hours. Mine has an "eco mode" that only heats during the scheduled filter cycle and that can be programmed to run at a specific time and it's pushing up on 30 years old so nothing new there.

James_s  - Thanks, I gave that some thought.  All of the relays are mounted on a circuit board and there are four different clean, heat, filter programs.  Just way to complicated.  Far easier to just install a high current relay after the GFCI and interrupt the mains power to the spa.  The spa's circuits have memory so the temp and other settings will all remain the same.  (I had another spa where the settings were not retained on power loss.)

In looking at posts in other forums getting others are doing exactly the same thing I am doing for AC units, electric heaters, pool pumps, electric hot water heaters etc.

Not sure if you read my other post, but the power company will change the amount of money they charge for a kWhr 5 times today for $0.12 to $0.54.
This $10 relay will save me over $1,000 in just 1 year.


 



 

Offline DougSpindlerTopic starter

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California law is if the fire happens after the earthquake you are covered by fire insurance. If the fire happens before the earthquake you are not covered.

Really?  Can you tell me where I find that law?

Why would you think fire insurance would not be valid after and earthquake.
Why yes I can.  Goes back to the San Francisco earthquake and fire in 1906.  And was again re-affirmed with the 1989 earthquake and fires.
 

Offline bson

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I wouldn't buy any electronic part that matters from Amazon.  Heck, I recently received Energizer CR2032 lithium cells from them that measured 2.7-2.9V across the board, pack of 20!  I discovered this after they went dead within a month when they should last 6-8 months.  Garbage.  Ordered Panasonic ones from Mouser; a touch over 3.2V across the board, priced $.23 per cell, qty 1. The Energizers were probably counterfit since any legit lithium cell should have a shelf life well over 10 years.  My best guess is they were really alkalines.  Just avoid.
 


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