DPDT Relay Help

Hwaiii · Joined: 02 Jun 2017 Posts: 6 Location: Simi Valley, CA

I wired the HLT and BK elements per the diagram. When I turn element select switch the element light comes on for both. However, when I plug in the element to test and turn switch, the light doesn't come on. I've used the multimeter to confirm there is 240v power to the DPDT relay, but when select switch is thrown, there's limited power flowing through even though it engages. Thinking I had bad relays, I ordered new ones and installed them, but am having the same issue. Any thoughts on what the problemmight be? Any help would be much appreciated! Thanks!

**kal** · Posted: Fri Jun 02, 2017 3:13 pm Post subject: Re: DPDT Relay Help

Hi and welcome to the forum!

Just to confirm, I take it you're building a standard 30A panel and you're using parts you're sourcing yourself and not from one of our kits correct?

Hwaiii · Joined: 02 Jun 2017 Posts: 6 Location: Simi Valley, CA

Hi Kal,

Thanks for responding. Sorry, I should've been more clear; yes, I'm building the 30A panel and sourcing the parts myself.

When I turn the Element Select switch to the HLT Element, the HLT Element light (only) comes on. The same is true for the BK Element light as well when I turn the Element Select switch to the BK (only the BK Element light comes on). This would tend to indicate the wiring was fine.

However, when I plug in the element and turned the Element Select switch to HLT to test the element and PID, the HLT Element light no longer comes on. The PID "OUT" indicator is on and the light on the SSR was also on. At First, I thought it was the Element cord or the Element (as your Testing/Troubleshooting piece suggested), but I used the multi-meter to check these and they seem ok. So, I used the voltmeter to measure the two HOT connection points on the heating element receptacles (as your piece suggests) and measured 75V. Further, if I have the controller power on and leave the Element Select switch in the "Off" position, I can measure 240V at the NO terminals of the DPDT relay. As soon as I select HLT or BK with the Element Select, the relay "clunks" and engages, but the Element indicator light does not come on and there's no longer 240V at the NO or Common terminals. As I mentioned earlier, I thought this meant a bad DPDT relay, so I ordered new ones and reinstalled one to test, but had the same experience. I'm not sure where to go from here.

I mimicked the image on your Heating Element Wiring diagram so the power into the element DPDT relays from the SSR's is connecting to the NO terminals (not the COM terminals). Could that cause this? If not, any suggestions?

Thanks!

**kal** · Posted: Fri Jun 02, 2017 7:59 pm Post subject:

Hwaiii · Joined: 02 Jun 2017 Posts: 6 Location: Simi Valley, CA

Thanks Kal! I'll check the SSR's.

**kal** · Posted: Fri Jun 02, 2017 8:53 pm Post subject:

No problem!

Keep in mind that SSRs, as solid state relays are difficult to measure when it comes to using a voltmeter. There's leakage current (like the 75V you're seeing) that is usually always shown on the output side even when they're 'off'. Very little current flows so they're almost completely off, but because of the slight current, a voltage will be shown. They don't show 0 or 240V like a physical relay like the other 3 you use.

Kal

Hwaiii · Joined: 02 Jun 2017 Posts: 6 Location: Simi Valley, CA

So, reporting back that I found the issue: it was the Element Light! On a hunch I disconnected the Element Light wires and now measure 240V to the receptacle. Haven't had a chance to see what the problem with the light is, but feel the problem's now solved. Thanks for your help!

**kal** · Posted: Sat Jun 03, 2017 3:20 am Post subject:

Excellent! Glad you figured it out!

So what was the issue with the element light exactly? Just curious...

Kal

Hwaiii · Joined: 02 Jun 2017 Posts: 6 Location: Simi Valley, CA

Not sure yet, but when I have a chance to figure it out I'll let you know.

Hwaiii · Joined: 02 Jun 2017 Posts: 6 Location: Simi Valley, CA

So, it wasn't the light after all. Turns out I had crossed the output wires from the SSR's to the DPDT relay. Switched them and everything is working beautifully now. Thanks for your help and patience Kal!

**kal** · Posted: Mon Jun 05, 2017 3:12 am Post subject:

Good stuff! Always better when you can explain the issue as now it's permanently gone! Cheers!

Kal