120V RIMS System Power Diagram Help

Troubs · Joined: 23 Feb 2011 Posts: 39

Hey guys, just about finished building my RIMS system. It will be a propane/electric combo. The HLT and Boil Kettle will be heated by propane and the RIMS tube will be using a 1500 Watt low density element. My control panel is yet another shameless rip-off of Kal's wonderful design. Obviously there are difference seeing as this will be a different system. The panel will control 2 pumps, 3 PIDS and the RIMS element. It will be powered by 20A/120V. Can anyone confirm that the diagram below will be appropriate for what I am trying to do. I have omitted a lot of the stuff from this diagram (grounds, power lights, etc.) in order to keep the diagram simple, mostly for my sake. Basically my question deals with the hot line and the use of the relay. I'm hoping to use both sides of the relay (one side for the power in and one side for the element). Can I use it in this manner? Thanks for the help! I can't wait to post the final pictures of the system once its done!

crush · Joined: 28 Dec 2010 Posts: 706 Location: Telemark, Norway

I don't think you can use it like this, since I'm fairly sure the relay has just one coil. Although there are two separate poles (each with 2 throws), the single coil operates both switches, so the poles are either both open or both closed at the same time. The two poles cannot be operated independently, which is what I think you are trying to achieve.

You'll need another power relay to shut off power to the element. Another alternative, although potentially less safe, is to not use a power relay on the element. Instead, place the element switch on the control signal to the SSR, so that turing the switch off stops the control signal. The -ve side of the SSR control from the PID goes to the SSR as normal, and also to the NC connector on the switch, and then to the SSR. So when the switch is in the off position, the SSR control signal gets 0V. The +ve side of the SSR control from the PID is connected to the NO contact on the switch and then to the +ve control on the SSR. So, when the switch is in the ON position, it completes the SSR control circuit and the control signal can flow.

Before you put this in operation, you should check that the SSR does block the current entirely. I've heard that a small current flows even when the SSR is switched open. This could potentially mean the element is run dry. This is why I say it's potentially less safe than having a separate power relay, which physically disconnects the power to the element.

PS: Great idea combining gas and electric. I was looking at getting a honeywell propane controller before I found this site. I've now bought all the parts and going fully electric, but there's a part of me kicking myself that I spent all that cash, when a cut-down version like this might have done the job! Good luck with the project!

Troubs · Joined: 23 Feb 2011 Posts: 39

Thanks for the reply. What you said makes sense. I did not know that the single coil operates both switches. Bummer. I have heard that the SSR does leak some juice so I'll definitely be checking this out before I run it for the first time. I'll post back when I've wired it up

crush · Joined: 28 Dec 2010 Posts: 706 Location: Telemark, Norway

I mentioned the alternative without an element power relay really just so you know of the options. Personally, I'd get the extra power relay and feel happy knowing the system is safer. If cost is what's putting you off using 2 relays, remember that it's not much compared to the rest of the cost! If it's size that's the problem, then maybe you can find some smaller relays. Since you're using 1500W element, that's about 12.5A at 120V, so you could use a much lower rated power relays than the 30A 240V, such as 15A 120V, which will presumably be smaller.

Troubs · Joined: 23 Feb 2011 Posts: 39

It wasn't a cost issue. It was more of a 'damn, I only got one when I should have gotten two' issue. I think I'll end up just springing for another relay to do it right.

crush · Joined: 28 Dec 2010 Posts: 706 Location: Telemark, Norway

Sounds good! You can keep the 30A relay you've got now, and use that for main power in (coil controlled from the power switch.) If you choose to add more elements/more devices later, you know it has the capacity to grow with you.

If getting hold of a another 30A/240V power relay is tricky, you can use a lower power relay for your rims element since it is drawing much less power. Lower power relays are probably more readily available, so you might have an easier time getting hold of one.

Troubs · Joined: 23 Feb 2011 Posts: 39

Alright, just bought another 30A/240V. I figure if I do go all electric at some point I'll have the relays for the job. Thanks a lot for your help Crush!

crush · Joined: 28 Dec 2010 Posts: 706 Location: Telemark, Norway

Anytime. Being a part time propane man, I'm interested to see how it goes! I'll still be keeping my banjo burner and the propane tanks, and I'm pretty sure the burner heats water faster (although not by much, and for considerably more cost of propane...although electricity prices have skyrocketed lately in Norway. We just got a bill for $1000 for 3 months electricity. It's normally about $150...) so having propane as a backup system might be wise!

Troubs · Joined: 23 Feb 2011 Posts: 39

Cool. As soon as I'm done I'll be sure to post pictures. I'm hoping to have this thing ready to rock in a couple weeks but it seems like there is always just one more thing to get/do!

dutch101st · Joined: 22 Feb 2011 Posts: 75

Here is how I wired mine:

I do both propane and electric (RIMS only); I will be building out a new box when I upgrade to Brewery 3.0 here in April. Brewery 3.0 will contain a new brew stand, new control panel with one PID, a timer, two pump control, RIMS heater kill switch, and alarms- the timer and alarm will be new as will the box and LEDs (Thanks Kal!)