Low Voltage Switch to 120v Water Pump

korz24

Joined Jan 23, 2020
6
Hi! Thanks in advance to anyone who could offer any information about this question.

I am looking to use a digital recycling timer to be able to turn a 120v water pump on and off at select timing intervals. I am currently using a
"AC110V-220V Digital Display Time Relay Automation Delay Timer Control Switch Relay Module" (pic below) but I need something much smaller due to spatial restrictions. The second pic is a wiring diagram of how we hooked up the old timer to the water pump.

I would like to try and use the Adafruit TPL5110 Low Power Timer to control the timer but it is only rated for 3-5v.(pic below)

So the money question, is it possible to power a 120v water pump on and off by using a lower voltage switch to disrupt the signal or do I need other hardware like a relay to do so? (while keeping it smaller than the original timer)

Thanks for any help! I will try to update if I find out any new info

sagor

Joined Mar 10, 2019
135
Pumps usually have a high starting current, thus you usually use a mechanical relay or a solid state relay to turn on the 120V AC.
You cannot control a 120V AC pump directly with those low voltage timers, you need some interface.
If you can find a good solid state relay (SSR), you can probably use that TPL5110 to drive the SSR. SSR have input ratings in the 3 to 24VDC range, make sure you get one that will trigger with 3 to 5VDC. Output rating is important as well, make sure it will handle the pump current.

SamR

Joined Mar 19, 2019
1,623
What you are needing is a 3-5VDC rated coil or SSR relay that has contacts rated for the starting current of the pump @ 120VAC. Do you know what the starting current is? If it's not rated for the starting current the relay contacts may weld together on startup. And Welcome to AAC!

korz24

Joined Jan 23, 2020
6
Pumps usually have a high starting current, thus you usually use a mechanical relay or a solid state relay to turn on the 120V AC.
You cannot control a 120V AC pump directly with those low voltage timers, you need some interface.
If you can find a good solid state relay (SSR), you can probably use that TPL5110 to drive the SSR. SSR have input ratings in the 3 to 24VDC range, make sure you get one that will trigger with 3 to 5VDC. Output rating is important as well, make sure it will handle the pump current.
Thanks for the response @sagor. So what would the order be in terms of circuitry? Outlet to TPL5110 to SSR to pump? Where does the SSR get placed and what type of current output would the SSR need? The pump doesn't list how much amperage it is rated for. It only says 110V and power of 2.5W. Again, thanks for the input!

korz24

Joined Jan 23, 2020
6
What you are needing is a 3-5VDC rated coil or SSR relay that has contacts rated for the starting current of the pump @ 120VAC. Do you know what the starting current is? If it's not rated for the starting current the relay contacts may weld together on startup. And Welcome to AAC!

Thanks @SamR! I do not know what the starting current for the pump is but is there any way I could figure that out? Because I don't know the actual rated current so I am guessing the starting current would be much more. Thanks again!

Joined Jul 18, 2013
19,685
If this is similar and small pump such as a sump pump etc, then most SSR are around 25a.
You mention a 120v pump, so likely in N.A. so if it is normally fed from a 15a socket, it cannot be that high.
Most sump type pumps are <10a.
Max.

korz24

Joined Jan 23, 2020
6
This is the water pump. It is the DB-300 by JAJALE but no further information on electrical ratings to be found. Is there anyway I could use a multimeter to test its draw?

Joined Jul 18, 2013
19,685
It is only a mere 2.5w so the current is trivial, so almost any power SSR will work. even a small relay.
Max.

korz24

Joined Jan 23, 2020
6
It is only a mere 2.5w so the current is trivial, so almost any power SSR will work. even a small relay.
Max.

ebeowulf17

Joined Aug 12, 2014
3,040
Thanks for the response @sagor. So what would the order be in terms of circuitry? Outlet to TPL5110 to SSR to pump? Where does the SSR get placed and what type of current output would the SSR need? The pump doesn't list how much amperage it is rated for. It only says 110V and power of 2.5W. Again, thanks for the input!
Two things - first is that the Adafruit board doesn't connect in any way to mains voltage or bad things will happen! You'll need a separate power supply to provide 3-5VDC to the timer module. The timer module output will connect to the control side of the SSR, and the load side of the SSR will switch the high voltage line to the pump.

The second issue is that I don't think this particular timer board does what you want. It has some odd behavior, including a requirement for some feedback from the device it's controlling. Maybe I'm misreading its instructions or misunderstanding your goals, but I think you'll need a different timer.

MisterBill2

Joined Jan 23, 2018
4,847
Hi! Thanks in advance to anyone who could offer any information about this question.

I am looking to use a digital recycling timer to be able to turn a 120v water pump on and off at select timing intervals. I am currently using a
"AC110V-220V Digital Display Time Relay Automation Delay Timer Control Switch Relay Module" (pic below) but I need something much smaller due to spatial restrictions. The second pic is a wiring diagram of how we hooked up the old timer to the water pump.

View attachment 197485View attachment 197487
I would like to try and use the Adafruit TPL5110 Low Power Timer to control the timer but it is only rated for 3-5v.(pic below)
View attachment 197486

So the money question, is it possible to power a 120v water pump on and off by using a lower voltage switch to disrupt the signal or do I need other hardware like a relay to do so? (while keeping it smaller than the original timer)

Thanks for any help! I will try to update if I find out any new info
The plain and simple answer is that you need a motor control rated switch of adequate rating to control the power to the motor. A solid state relay of the correct rating can have a control input that requires 5 volts at 20 to 50 milliamps. CRYDOM is a brand that has a wide range of solid state power relays. They also make similar products that will be controlled by other voltages.

THis thread seems to be very similar to another thread that has wandered along for quite a while.

Joined Jul 18, 2013
19,685
It has already been suggested of using a SSR, the typical inputs are 5v - 30vdc control voltage, and the pump is only 2.5w!
Max.

oz93666

Joined Sep 7, 2010
724
View attachment 197492 This is the water pump. It is the DB-300 by JAJALE but no further information on electrical ratings to be found. Is there anyway I could use a multimeter to test its draw?
This looks like a brush-less DC motor pump ... electronics inside turns mains into low voltage DC

You might want to think about changing this pump to low voltage DC ... many different types available on eBay for a few $, and you will keep the mains supply away from water ...always a good idea Thread Starter korz24 Joined Jan 23, 2020 6 I appreciate all the feedback from everyone helping me out in this forum! Would there be a better possible setup instead of trying to use the Adafruit TPL1150? All it would need to do is be able to program time intervals that turn the water pump on or off and within a reasonable space. I have looked online quite a bit and cannot find anything that I think would work but didn't know if anyone else had used something similar before. MisterBill2 Joined Jan 23, 2018 4,847 This looks like a brush-less DC motor pump ... electronics inside turns mains into low voltage DC You might want to think about changing this pump to low voltage DC ... many different types available on eBay for a few$ , and you will keep the mains supply away from water ...always a good idea
The pump in the picture is rated at 120 VOLTS AND 2.5 WATTS on the clearly visible label. So that says that the current is about 2.5/120 amps, about 0.2 amps, which is not much. And at that size it is probably driven by a small induction motor.. and it is a complete assembly, not a bunch of parts cobbled into something.
So nowI have a question as to exactly what the pump is intended to be doing, since it is a very small pump such as might be used in small garden fountains in a house.
And here is a serious note of caution, which is that the timer system is switching mains connected power, and so it is important to assure that there is no contact with any of the 120 volt AC wiring.

ebeowulf17

Joined Aug 12, 2014
3,040
Without knowing why your space is so tight, nor what the available space is like, it's hard to guess what you really need. Honestly the module that you said you're replacing is exactly the sort of thing I would've recommended. Unfortunately, any module that does what you want directly (working directly from the high voltage lines, not requiring separate power supplies, etc.) tends to be bulky compared to low voltage stuff - it just has to in order to be safe.

Anyway, the most compact arrangements I can think of would use a very slim, low voltage timer module in conjunction with a small SSR - this plan assumes you can have a power supply somewhere to feed it, maybe just a little wall wart USB 5V supply or something.

I haven't used them and can't vouch for them, but there are tons of premade modules online with various timing capabilities. This one looked interesting to me:

More details at:
http://timers.shop/Multi-Functional-3V-18V-Time-Delay-Relay-Timer-5-amp_p_12.html

And here's one example of a relatively compact SSR that might work (I haven't checked all the specs, but at first glance it seemed plausible.)

https://www.digikey.com/product-detail/en/sensata-crydom/EZ240D5/CC2176-ND/752093

MisterBill2

Joined Jan 23, 2018
4,847
The pump control shows + 1 2 3 4 - on the outside control?
It is a submersible aquarium pump with PM motor rotor, so I suspect it is some kind of BLDC. Which would indicate a AC fed BLDC control of some kind built in.
Max.
That numbered control is probably a bypass valve adjustment, not some sort of waterproof switch, Max. And I have come across PM synchronous motors in the past. A simple coil with alternating poles and so it runs at a sub-multiple of synchronous speed. Why always insist that all consumer stuff embraces the very latest in technology, when really it uses the very cheapest that can possibly be made to work for a while.