Electric kettle with PID control

[neo82087]

I'm trying to figure out how to wire up a 220v 4500 watt heating element to a PID. The diagram that I'm thinking of following is located here

My concern is that 110v will be running directly to the heating element. I don't know if that would cause a problem or not. Anyone with some electrical ability have any input?

Thanks

 

[wihophead]

It wouldn't cause a problem per say but it would be wise choice to either use an additional SSR for the other hot leg or substitute the 2 SSR's for 1 SSRD.

 

[neo82087]

How does this look?

My only question now is how to I ensure that the circuit is grounded? What do I ground the connection to on the side of the heating element?

Thanks.

 

[drez77]

To ground the element you have to create a place to attach the ground wire. On my HLT I soldered a piece of copper to attach the ground wire to. Here is another example. http://essersnet.com/php/content.php?viewPage&ID=200 . If you are using a keggle you can attach the ground to the skirt of the keg with a bolt.

mike

 

[stevehaun]

Several suggestions:
1. Place a 30 amp, double pole switch between the terminal strip and the SSRs. In this manner, you will be able to turn the element off with the flick of a switch. Also, with this switch, two SSRs are not necessary - one will be sufficient.
2. Is your PID rated for 240 VAC? That is how you have it wired.
3. You should move the inline GFI to the powercord end of your system.
4. Ground everything. The kettle, the double pole switch, and the enclosure should all be grounded.
5. You may want to add a switch to your PID.
Lastly, have an electrician or electrical engineer review the project before you plug it in.
Have fun!

 

[stevehaun]

One more thing - you really need a 30 amp GFI.

 

[neo82087]

Do you happen to know where I could find a 30 amp GFI? I have had trouble finding GFIs rated for 240v. The PID I have has a power supply voltage rating of 85~264VAC/50~60Hz.

 

[wihophead]

You would have to use a 4 wire system so you could get 120 volts for your temperature controller unless it is rated for 220V but I doubt it is. Doing this will also make it impossible to put the GFCI on the cords line side since the load will not be balanced. If the load is not balanced the GFCI will trip.

We use 20A 220V GFCI's here let me get the info off of it and see if they make a 30A.
Another option is to use a 30A 2 pole GFCI breaker but then you would have to use a transformer or separately power your temperature controller since the load will not be balanced as stated earlier.


I just noticed that the SSR triggers are wired directly to the output of the temperature controller. I know nothing about the specs of the unit you are using but the Watlow units we use are either relay or ssr type so if this is the case you would also need a DC supply if they use a DC input or you would need to grab 120V if they use an AC input.

Posting model numbers would really help.....


Edit:
The only high power GFCI's that I found by the manufacturer that we use are designed to protect equipment and not persons...sorry

 

[neo82087]

http://auberins.com/index.php?main_...s_id=3&zenid=aae4c01968db34954dbcfa095f3c2741

Would it instead be possible to wire up two 110v 1500 watt elements? How would I do this instead? Thanks for all of the help.

 

[wihophead]

It appears that the controller you picked has a 12VDC output so it will work as you intended.

You could parallel two 1500W 120V heaters very easily and you still will be looking at a 30A circuit. Will that setup give you enough heating power???

 

[processhead]

I am using a similar controller and heating element circuit in my RIMS system. I operate the 4500 watt 240 VAC element on 120 VAC.

I think that this gives me the heat output I need because I am only heating 2-3 gallons of mash liquor and recirculating it though the mash at relatively low mashing temperatures.

One side of the element is wired to the system neutral. The 120 VAC side of the element is switched through a SSR. It is unnecessary to use two SSRs for switching the current to the element. One SSR will switch all the current to the element.

I use a 20 GFCI for circuit protection on my system. BTW it is possible to purchase GFCI circuit breakers that protect the whole circuit from your breaker panel. I believe they are a little pricey, however.

Not sure how you plan to use your kettle but if your were planning to heat a large volume of liquid to higher temperatures, you may want to use 240VAC to give you the full power output of the element.

If powering the element with 240 VAC, I think I would use two SSRs.

Always bond all metal components in your system to the ground conductor of the line cord to protect yourself from an accidental short between an energized conductor or element and the tank/liquid contents.

 

[stevehaun]

So your PID can be run on 120 or 240 VAC. With DC output from your PID, your SSR will need to be switched by DC input. You don't need to control both limbs of a 240 VAC circuit. You can use 2 SSRs but it is overkill. See this link from Watlow describing how to wire a resistive load with 240 VAC controlled by SSR:
http://www.watlow.com/literature/prodtechinfo/files/controllers/ssre_c.pdf
I do think it is important to use a manual switch on your heating element - this should be double pole to control both limbs.
I think you would be wise to get a GFI breaker. You can find 50 amp GFI breakers on ebay or at Home Depot for less than $100. I also agree that you should use a 4 wire power cord and the wire should be 10 gauge.
Have fun!

 

[mr x]

You are going to want that heat sink on the SSR as well.

I have done this before with a Watlow controller on an essential oil extraction pot. I stopped because I found that when the cycle time is too long, you can hear the boil stopping and starting, which isn't what I wanted. If you make the cycle time too short, you will find your lights flickering like crazy (and that isn't good for the other electronics in your house either). Also, I think it is illegal to switch power like that off a residential power feed.

 

[neo82087]

With a 4 prong 240v cord, what do I do with the neutral wire? How would the diagram that I posted on the previous page differ?

 

[wihophead]

With a 4 prong 240v cord, what do I do with the neutral wire? How would the diagram that I posted on the previous page differ?

Actually as stevehaun mentioned the temp controller you are using is rated for 240VAC (sorry I missed that and you even said it earlier..LOL) so you wouldn't need to use a 4 wire system only 3 wire so actually the diagram would work just like you have it except for the GFCI which should be a 30A and ideally be on the line side. You would want to use a 30A GFCI breaker (it may actually be cheaper and easier to use a Hot tub disconnect if you are comfortable with wiring and working in you main panel) and you would use 10AWG as stated above.

Also I still recommend using a second SSR since it is always good practice to open all ungrounded current carrying conductors when the load is not on.

If you locate a Hot tub disconnect near were you are using this it could be used as a disconnecting means also.

 

[stevehaun]

One advantage of having a 4 wire is that you could power your PID with 120 VAC if you wanted to. In addition you could run your pump (presumably 120) off the same terminal strip.
You definitely want to use heat sinks for your ssr(s). They are cheap - I think I paid about $12 each for mine.
I also fused my SSRs. However the fuses cost almost as much as I could buy SSRs on Ebay.
When I run my boil kettle, I use the PID in %power mode (manual override). I simply turned down the cycle time until I no longer noticed the on/off effect on the boil. My lights don't flicker and I am using two 4500 watt elements. I think it may depend on the size of service at your house's load center. My load center has 200 amp service. Older homes often have only 100 amp service and it would not surprise me if it would make your lights flicker if you had 100 amp service..

 

[mr x]

Wow, you must have a wicked grid if you can switch 9000 watts with no effect. Not so lucky here...

 

[neo82087]

I've decided to bump the power down to 3000 watts so I can use the 20 amp 240v in-line GFCI instead of installing a GFCI breaker since I do not have access to the master switch in my apartment building. It'll make my brew day a bit longer, but I'd rather have proper safety equipment in place. The one thing that I am a bit confused about now is the 240v plug. I have 4 prong outlet but I am not sure how I would wire up the 2 hot + 1 neutral + 1 ground instead of the 3 prong plug. Is it possible to plug a 3 prong plug into the 4 prong outlet? Just want to make sure I have things right. Thanks to everyone who has been helping.

 

[stevehaun]

You can run your neutral to the terminal in your enclosure. You would only need to wire to the neutral if you use 120 vac - your PID or pump or indicator lights.

 

[dixon72]

I am a little confused by the schematic. I thought the use of an SSR was because most PID's can not handle the current from a heating element.

It looks to me like the PID is powering the element through terminals 9 and 10, so wouldn't the PID be taking the full load from the element still?

Am I not seeing this correctly?

Does this PID have an amp rating commensurate with the load of the heating element?

I only ask because my plan was to use a schematic similar to the Brutus 10. I was not planning on using the PID to route 120v through the SSR to the heating element. The only voltage from the PID I was going to use was the DC to switch the SSR. I was going to essentially route power from the wall, running in/out of the SSR and to the heating element.

Is this not correct?

Thanks for any clarification.

-Dixon

 

[wihophead]

I am a little confused by the schematic. I thought the use of an SSR was because most PID's can not handle the current from a heating element.

It looks to me like the PID is powering the element through terminals 9 and 10, so wouldn't the PID be taking the full load from the element still?

Am I not seeing this correctly?

Does this PID have an amp rating commensurate with the load of the heating element?

I only ask because my plan was to use a schematic similar to the Brutus 10. I was not planning on using the PID to route 120v through the SSR to the heating element. The only voltage from the PID I was going to use was the DC to switch the SSR. I was going to essentially route power from the wall, running in/out of the SSR and to the heating element.

Is this not correct?

Thanks for any clarification.

-Dixon

The temperature controller is powered via a parallel connection with the elements and terminals 7 and 8 power the SSR triggers. So no the controller is not carrying the heater element load the SSRs are. My only real complaint about the diagram is the wire color coding....

 

[neo82087]

It was done in haste Thanks for the feedback, I'll keep this thread updated with my progress as I get some time to work on it after the holidays.

 

[dixon72]

I see now...I guess I didn't see the input power from the wall to B and C of the bus. Thanks for helping me understand.

-Dixon

 

[scoates]

Also, I think it is illegal to switch power like that off a residential power feed.

Does anyone have any info on this?
Isn't this how switching power supplies work?

S

 

[slnies]

I think that you are over looking the other possible avenues. Hot tubs are wired with GFCI's. Hot tubs as a rule are multi voltage units. 120/250 Volts nominal is the norm. A GFCI by design monitors fault voltage to ground, or stray voltage coming from the grounding conductor not the neutral or the grounded conductor. You could find a 30 amp 2 pole Square D GFCI Breaker and enclosure at Menards or home depot. The cord could then be wired to the enclosure and then you could run a power cord to your apparatus from the enclosure. These enclosures are rated as NEMA R3 witch is weather resistant. They are made to be exposed to the elements. This would protect the whole of the system. To answer the unbalance load question, any 110, 120, or 277v circuit that is one phase to ground is unbalanced by nature. A 208v, 220v or 480v Circuit is a phase to phase voltage and is balanced its nature. As for the PID If you list the manufacture, model, and Cat# I could look at the wiring diagrams and give you some guidance on how to hook it up for your application.

 

[slnies]

Sorry about the rant, i did not see that there were three pages to this thread.

 

[slnies]

Does anyone have any info on this?
Isn't this how switching power supplies work?

S

Yes, and no it is not illegal on residential power or at least the NEC does not forbid it. How ever According to that same NEC unless all of the parts of the system are listed for the intended use or for use with the individual parts of the system. you would be in violation. The way around is to have a EE approve the drawings and UL list the system. This however is not practical for use lowly Home Brewers.

 

[scoates]

Thanks Nies.

I've actually been spending the last few nights wiring up my new kettle.
My controller is based off a LM555 circuit I whipped up for duty cycling (once boiling), a 25A SSR, and is GFI protected with a 30A cord I got on ebay for ~$80 (shipped, to Montreal).

Will post more once it's done..

I'm not going to leave it plugged in (ie, it's non-permanent; I'll plug it into my dryer outlet) so it's less likely I'll get screwed if my house burns down from something unrelated. Wouldn't want Hydro-Quebec goons showing up at my door, though (-:

S

 

[slnies]

Thanks Nies.

I've actually been spending the last few nights wiring up my new kettle.
My controller is based off a LM555 circuit I whipped up for duty cycling (once boiling), a 25A SSR, and is GFI protected with a 30A cord I got on ebay for ~$80 (shipped, to Montreal).

Will post more once it's done..

I'm not going to leave it plugged in (ie, it's non-permanent; I'll plug it into my dryer outlet) so it's less likely I'll get screwed if my house burns down from something unrelated. Wouldn't want Hydro-Quebec goons showing up at my door, though (-:

S

Cool, I am actually in the process of switching from LP to electric myself. I was was thinking the other day that since I am an electrician I should have a brewing system that reflects my roots. That is my story and I am sticking to it. It sounds like you are on the right track. My own opinion is as long as it has built in protection for you, than " let her rip". Enough said. S Nies

 

[neo82087]

I've got my controller box all wired up, and I'm just doing some final checks. With the GFCI, will it be a problem not having the neutral connected to anything on the kettle side?