Parts needed?

Hey guys, I'm putting together a E-HLT and I need help choosing the right size (water heater) element and SSR. I have a 20A 250v outlet on a 20A breaker and nothing else is on the line. I have allready purchased a mypid ta4 controler. Here is a pic of the setup I will be using. Any input is appreciated.

Thanks
Chris

 

Watts / Volts = Amps

3500W / 240 = 14.6 amps
4500W / 240 = 18.8 amps
5500W / 240 = 22.9 amps

assuming you are going to put some sort of selector switch to select only 1 element at a time? 4500 ultra low watt density (ULWD) is your best bet. you can use a contactor to do that but i doubt you'll be able to find a DPDT switch hardcore enough to handle 20 amps of 240v.

i assume that SSR you list is a 25amp based on the part #? if you can, get a higher rated SSR, it'll get less hot as it isn't as close to its limit.

 

I was not planning on using a selector switch... I was just hoping by using two elements it would use less amps.

So basically I need something under 80% of 20Amps. It does not matter how many elements.

Will a single 3500W / 240 = 14.6 amps element heat up and maintain my HLT to 175 degrees?

And is the bigger the SSR the better? say 40A?

 

Sorry I suck at electrical work, and I have read a weeks worth of sticky's on this lovely forum about E-Brewing and I still need help. :smack:

 

you want 1 3500 or 4500 element. remove the second one from the diagram. the 80% rule doesn't apply to you. that's NEC code for circuits at install when other devices may be added to the circuit later.

a 4500W element will do a great job in an electric HLT up to about 15 or 20 gallons.

a 40 amp ssr will stay cooler and last longer than a 20 amp ssr switching a 20 amp circuit.

now, all that being said... if you don't really understand what i posted originally, maybe building your own electric circuit isn't a good idea. water + electric = death. i see no mention of your GFCI protection, no ground anywhere in your diagram. both of those are HUGE issues. proceed with caution.

 

Thanks slakwhere. I was going to look for a GFCI that is built in the power cord or is it better to have a GFCI outlet?

 

Ok here is my revised wiring diagram. Now my question is... can I use a switch like this one

http://www.ebay.com/itm/PBC-SS22CPMA-2-INO-INC-2POS-Maintained-Selector-Switch-/390143796261?

If I get a relay like this one?

http://www.amazon.com/dp/B003U7Z8Q6/?tag=skimlinks_replacement-20

And will I need a transformer for the switch?

 

you definitely need a contactor to switch that big of a 240v load. that contactor requires a 24v transformer to trigger.

so you'd go 120v -> transformer -> switch -> contactor coil

240v -> contactor -> SSR in -> SSR out -> element.

you still don't have any grounds listed anywhere in your diagram

 

Can I ground the control box with a post and ground everything to that?

 

Why a 24V coil for the contactor as opposed to a 120V or 240V coil? Do you have a need for a transformer in your control panel?

The switch listed on ebay does not list the voltage (or I missed it).

 

I though it was.
So basically I just need 240v 40A contactor for that switch?

 

i assumed he was using them since they are usually cheaper than the 240v coil variety. but i guess i should have said something.

if possible you for sure want a 120v coil or a 240v coil for the contactor. and the contacts should be rated for 240v 20a or higher. for a few bucks more, i'd raise the rating of the contacts.

 

Ok so my biggest hang up is using 240v vs 120v Every thing I read seems to talk about 120v if I copy Kol's wiring, Will I need a transformer for the indicator light? or should I just not use a light?



Will this same setup work with my 240v 20Amp service?

I can use 120v if you think it would be easier.

Thanks again for all the help I am learning as I go and promise not to plug this thing in to the wall until further review.

 

120v uses 1 hot, 1 neutral and 1 ground (which you are STILL ignoring).

240v uses 2 hot, 1 neutral and 1 ground. the 2 hot lines are basically alternating phase 120v. take either hot leg, a neutral and a ground and you get 120v. take 2 hot, a neutral and you get 240v.

this diagram will not work for 240v. you do not understand how 240v works. you're missing 2 inputs to the plug, there's no ground. i have no idea why that 50a shunt is there. there's no heating element in the diagram, so this is a really elaborate switch that turns on a light bulb.

please, for the love of pete, find a buddy who has an electronics background to help you locally. you're missing a LOT of stuff. you're going to burn your house down, electrocute yourself or blow up a lot of gear. most probably all 3.

 

Actually, 240v does not have a neutral, as 2 hots will do, with a ground for safety. I absolutely agree with your last point though. The OP really should not be undertaking this without a much better understanding of the workings.

OP, if you keep studying Kal's site, and you get to the point where you really understand how it works and why it is wired the way it is, then consider undertaking the project. Otherwise, get some help (and it's never a bad idea to get a second pair of eyes, in any case).

Lastly, the picture you included is one of Kal's intermediate wiring steps. E.g., it does not show the seocnd hot leg, as at that point in the instructions he had yet to connect it.

 

it doesn't HAVE to have a neutral (240v heating elements don't have a neutral, just 2 hots) ... but it's in your box, it needs to be accounted for.