Anybody knows how many relays I can drive from Pentair's AUX circuit?

[crusius]

Hi all,

I am about to re-arrange my relay setup (in a Pentair EasyTouch), and I'd like to use some wiring trickery to get some automation that is not possible with the EasyTouch and my equipment (a SuperFlo VS). For example, I'll set it up such that when the solar turns on, the pump speed goes up to ensure the SWG has enough flow.

The simplest wiring trickery to achieve this will result in an AUX (or the Pump) relay signal to have to drive 3 relay coils. (I'd have use for 5 if that's possible.)

Consulting the relay data sheet tells me each coil will take about 80mA of current at the 24V provided by the Pentair. My question is whether anybody knows how much current the EasyTouch can provide - with 3 relays that's about 250mA, or 6W, and with 5 relays that would be almost 10W. Since that's not trivial I thought I'd ask - could not find it in the Pentair manual. Worst case I'll pull an auxiliary 24V line from the power supply.

Thanks!

 

[ajw22]

I think folks have powered two relays from one socket. Three relays may draw more power then what the relay driver chip can handle and burn out the chip.

Let's see what @ogdento thinks.

 

[ogdento]

the easytouch uses a uln2803 to drive the relays, one "darlington pair" per relay... the spec sheet says each darlington pair (let's just call it an output) can sink 500mA so you "should" be ok with 250 (I probably wouldn't run 5 coils off one output). Keep in mind 500 is an absolute maximum rating - and if 3 coils are energized for a long time the chip will get hot, and if all the other outputs are "on" you might exceed the total power dissipation for the chip. but they're socketed, and only a dollar apiece so get some spares

if you blow the chips just go with one relay to switch 24v to your 3 or 5 other relays like you were thinking.

how many aux does your easytouch have (can't tell if you've got a 4 or an 8)?

 

[crusius]

the easytouch uses a uln2803 to drive the relays, one "darlington pair" per relay... the spec sheet says each darlington pair (let's just call it an output) can sink 500mA so you "should" be ok with 250 (I probably wouldn't run 5 coils off one output). Keep in mind 500 is an absolute maximum rating - and if 3 coils are energized for a long time the chip will get hot, and if all the other outputs are "on" you might exceed the total power dissipation for the chip. but they're socketed, and only a dollar apiece so get some spares

if you blow the chips just go with one relay to switch 24v to your 3 or 5 other relays like you were thinking.

how many aux does your easytouch have (can't tell if you've got a 4 or an 8)?

That's great info, thanks!

I have a PL4, and I see 8 aux outputs on the board (one for the pump). Yes, I think it is better to just get an extra 24V lead out of the transformer in the end, just trying to figure out now a neat way to do it - what sort of connectors to use to split that 3.96mm header on the board.

Thanks again!

 

[ajw22]

That's great info, thanks!

I have a PL4, and I see 8 aux outputs on the board (one for the pump). Yes, I think it is better to just get an extra 24V lead out of the transformer in the end, just trying to figure out now a neat way to do it - what sort of connectors to use to split that 3.96mm header on the board.

Thanks again!

Relay connectors are 2.5mm-pitch 2-pin female JST XH-style connector

 

[crusius]

Relay connectors are 2.5mm-pitch 2-pin female JST XH-style connector

Thanks! I meant the power connector though, which gets 24VAC and two other pairs (12 and 18?). I'll probably get two leads from the 24V pair there. It is a 3.96mm connector (I found the exact one, it is in page 12 in this brochure, Alex 9255). Maybe I'll just splice the original cables, less trouble than trying to get all the components...

Thanks again!

 

[JamesW]

which gets 24VAC

The relays are 24 VDC, but you can get AC.

Maybe just get a separate transformer to drive all relays at once from a single relay.

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[JamesW]

You can have one relay that provides power to as many relays as you like at 24 volts AC.

Whoops, we couldn't find that.

https://www.digikey.com/en/products/detail/cit-relay-and-switch/A3F1ASQ24VDC2D/12503424

https://www.digikey.com/en/products/detail/cit-relay-and-switch/A2M1ASQ24VDC1-6/12503065

 

[ogdento]

If you've got a pl4 and are going to all the trouble to fashion power connectors etc, it's probably easier just to convert to an et8 and program the 4 extra aux circuits you'll have to all turn on at the same time.

Look at the back of the board and there should be a tiny sticker with 2.something listed on it... That'll tell us the firmware on the board. As long as you have a newish firmware you can solder on the 2 1k resistors (r41, r42) and snip the mod telspa jumper

 

[crusius]

If you've got a pl4 and are going to all the trouble to fashion power connectors etc, it's probably easier just to convert to an et8 and program the 4 extra aux circuits you'll have to all turn on at the same time.

Look at the back of the board and there should be a tiny sticker with 2.something listed on it... That'll tell us the firmware on the board. As long as you have a newish firmware you can solder on the 2 1k resistors (r41, r42) and snip the mod telspa jumper

Thanks, did not know about that possibility - the "version" sticker on the board says "1.000" though, with a date from 2014. That route is probably out.

 

[crusius]

You can have one relay that provides power to as many relays as you like at 24 volts AC.

Whoops, we couldn't find that.

https://www.digikey.com/en/products/detail/cit-relay-and-switch/A3F1ASQ24VDC2D/12503424

https://www.digikey.com/en/products/detail/cit-relay-and-switch/A2M1ASQ24VDC1-6/12503065

Thanks! Yes, I'd have to either (a) get AC relays and just get 24AC from the existing transformer, or (b) get a small 24DC supply in there and keep the same relays. (b) is a lot cheaper, probably what I'll end up doing.

(Edit: something like this)

 

[ogdento]

ahh, ok then you'd need a firmware update... you can diy that (there's another thread on it at tfp) or send it to somebody who can do it for you. or just keep going with your relay work

 

[crusius]

ahh, ok then you'd need a firmware update... you can diy that (there's another thread on it at tfp) or send it to somebody who can do it for you. or just keep going with your relay work

Oh, sorry - completely missed it by staring at the (readable) "v 1.000" sticker I have. That other sticker has "v 2.130" on it. Seems to be right on the edge of "can/can not" convert?

I do need some relay work in any case: my plan to get a "Solar valve is On/Solar valve is Off" is to get an AC relay to feed out of the valve (AC) signal, and switch on a 24DC line to another relay to up the pump speed. At least I could find no other (programmatic) way to do that.

Thanks all for the help!

 

[ogdento]

You'll need new firmware... Starting with 2.150 you don't need to upgrade because the code is the same

 

[crusius]

You'll need new firmware... Starting with 2.150 you don't need to upgrade because the code is the same

Thanks! When the time comes I'll just sent it to somebody who can upgrade it for me. For now, just back from getting it finished - 8 DC relays and 1 AC relay and it looks like it is finally doing what I want it to do - only needed AUX1 and AUX2 outputs (plus a splice out of the solar valve for the AC relay).

Thanks again!

 

[JamesW]

What are you trying to do?

Can you just power everything from a single relay?

 

[crusius]

What are you trying to do?

Can you just power everything from a single relay?

So this is what I am trying to do, sorry if it gets long:

1. I have a SuperFlo VS pump, and I can select three speeds from its control wires. Given electricity is expensive here ($0.50/kWh), I want the minimum speed to do the job, and I don't want the pump connected to power all the time. This means:
   • Running speed 1 (1600RPM, ~250W) if solar heating is not on, and the booster pump is not on.
   • Running speed 2 (2200RPM, ~500W) when solar is on.
   • Running speed 3 (2500RPM) when booster pump is on.
2. The PL4 filter pump circuit triggers a relay that (a) connects 240VAC to the pump, and (b) turns on a 24VDC power supply that provides a "pump is on" signal to other relays. This signal (c) turns on the SWG relay, and (d) turns on the Speed 1 signal to the pump.
   • This sets the basic mode: pump turns on, SWG turns on (only when pump turns on), at Speed 1.
3. When the PL4 turns on the solar valve automatically, it sends a 24VAC signal to the valve on the black/white wire pair. I tap into those wires and connect them to the coil of an AC relay. This switches the 24VDC "pump is on" signal that triggers a second relay that turns on the pump's Speed 2 signal.
   • This ensures that when solar is on, the pump is running at a speed that keeps enough flow going.
4. Finally, I assign the booster pump to AUX1, and when that turns on, the 24VDC "pump is on" signal is connected to two other relays: the booster pump relay, and the Speed 3 relay.
   • Booster pump is only turned on when the pump is on, and increases the pump speed to ensure proper operation and extra skimming.

(AUX2 is a dedicated pool light circuit)

So that's that - a lot of wiring but does what I want it to do.

Now to figure out why the PL4 will not turn off my pump in AUTO mode even with delays canceled. All it does is turn solar on and off (?). It works fine in SERVICE mode. Good grief this thing is unintuitive...