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Electric heating element controller design

Posted: Wed Jan 23, 2013 10:43 pm
by gleamingthecube
Greets all. I have been reading and reading about distilling and related equipment over the last month or so and I have come to a conclusion. I am a dunce when it comes to electronics. I see that many people here on HD and out in the greater world post these snazzy little electronic diagrams with squiggly lines and such that are supposed to mean something but I have no clue how to read them. Might as well show them to my dog. Anyhow, I need a hand interpreting one such diagram and a critique of my plan for a heating element controller. Here goes:

I want to build a controller like was done here with but one modification. I want to add a 120v (1500w) element and a switch for it to the mix in addition to the 240v (5500w) that a controller like that would normally power. I don't have the circuits to run two 240v heating elements so I thought that the extra 120v element would help reduce heat up times without the need to hire an electrician. As many have said on here, I can turn the extra element off once I reach operating temperature (hence the need for the extra switch). The controller will not be connected to the 120v element. I will simply use the switch to power it off when heatup is complete.

1. This is a bit different from the designs I have seen posted here. Any reason that it won't work? Looks similar enough but has more bells and whistles, errrrm I mean useful features.
2. I know I am using cheap Chinese parts from ebay but the total cost is remarkably low compared to a retail solution or a PSR-25 based controller. Anyone used any of this stuff before? Am I throwing my money away?
3. Can I run the extra element off the neutral 120v wire of the 4 wire 240 cable or will I need to put a separate 120v power cord on this to power the extra element? If neutral can be used, can I route the neutral wire through a switch?
4. Is a 15a switch enough for the 120v pushing that many watts? (15*120=1800 I am guessing that I should be ok, being that the element is only 1500w?) I would prefer an expert's opinion to my own novice speculation.

Ok those are my questions for now. I am sure I will have more as this project progresses. Thanks in advance for any and all that respond. :)

-Cube

Re: Electric heating element controller design

Posted: Thu Jan 24, 2013 4:59 am
by bellybuster
Why bother even controlling the 120 element, plug'er in. You will need control of the 220 element though

Re: Electric heating element controller design

Posted: Thu Jan 24, 2013 5:01 am
by bellybuster
Oh, and no I would not run a second element leg off the 220 line and use both at the same time. Electricity takes the path of least resistance.

Re: Electric heating element controller design

Posted: Thu Jan 24, 2013 9:37 am
by gleamingthecube
I am not planning to control the 120v element. I am simply putting a switch on it so I can turn it off. It will not be connected to the controller at all. Perhaps I didn't explain what I wanted to do very well. Basically the 120v and its switch will be separate but in the same housing. I thought that if the neutral leg of a 4 wire set up can power the lights and clock on an oven that it could also be made to power my smaller element. If not, so be it. I just thought it would be wise to check on it and maybe avoid having to plug in 2 cables to power this thing.

Re: Electric heating element controller design

Posted: Thu Jan 24, 2013 11:24 am
by sambedded
If you need more power - install second 240v dlement but 1200- 1500Watt and connect it in parallel with 5500Wt element. This way you control all power by one controller. just doublecheck if your ssr and all your wires and switches 30+ Amp rated.

Re: Electric heating element controller design

Posted: Thu Jan 24, 2013 1:32 pm
by bellybuster
How big is your boiler that you need that much heating power?

Re: Electric heating element controller design

Posted: Thu Jan 24, 2013 3:23 pm
by gleamingthecube
@Bellybuster: I have a 15 gallon Brewhaus boiler on order. It will be a while before it gets here since they are out of stock until march and I am having ferrules welded to it for the heating elements. I hear that a single 5500w element takes too long to heat up on a boiler this size. Hence the desire for a 2nd element. I want to try and have everything else ready by the time that boiler arrives.

@sambedded: I am a total idiot when it comes to electronics. Is there an easy way to do what you are suggesting by wiring them together?

Re: Electric heating element controller design

Posted: Thu Jan 24, 2013 3:44 pm
by Theo
A 5500 watt heater should be plenty for a 15 gal boiler. Find one of your friends (or your dog) that understands electricity. It will minimize excitement & frustration. :crazy:

Re: Electric heating element controller design

Posted: Thu Jan 24, 2013 5:36 pm
by gleamingthecube
Ok so just one element should do? What kind of heat up times can I expect with a single 5000w element on say a 12 gallon batch of wash?

Re: Electric heating element controller design

Posted: Thu Jan 24, 2013 5:59 pm
by Prairiepiss
There's a calculator on the parent site for telling you this.
But a 5500 w element will heat 12 gal of water to boil in 49 min.
If you add 1500w you gain 10min. But what's the need. Real world it takes me around 40min to get 11 to 12 gal of wash to boil. I have a second element in my boiler from when I ran it on 110. After going 220. I've never even felt the need to plug the other one in.

Re: Electric heating element controller design

Posted: Thu Jan 24, 2013 7:47 pm
by gleamingthecube
Ok thanks I guess nevermind on the extra 110v element. I have looked over that calculator on the parent site but never quite did understand all the different numbers. Thanks PP you probably saved me some headaches and money. :)