Hello all, first post. I’m an operating engineer at a large high-rise hotel, and I’m looking to improve the chemical feed pump control in one of our boiler rooms. Briefly, I’m wanting the three feed pumps to run whenever a boiler feed pump is running. Since we have three boilers which can run independently, I’m wanting a selector switch to designate the ‘lead boiler’. (The three pumps are one per chemical, not one per boiler…all three pumps feed a common condensate return/feed tank.)
I originally tried a BACO 3-position switch from McMaster. Unfortunately, the specs weren’t clear and when I got it ready to install I realized that it could not be configured as I wanted; the center position was always “off”. So I’m trying again. Ideally I’d like to find a four-position-with-OFF (or five position and leave one unconnected) selector switch; one position for each of the three boilers and one override to turn the circuit “ON”. The boiler feed pumps are 460V 3-phase with 120V AC control power through a control transformer. The idea is to connect the solenoid for each contactor to three positions of the selector switch, plus a fourth always hot wire, with the single pole output going to a 30A relay connected to a separately breakered 115V circuit; when the relay pulls in it will energize the wall socket which the chemical feed pumps are plugged into. (Previous operators wired the current setup so that the outlets were fed directly from the control power…but after I looked it over and saw that the pump motors were rated for 1 amp each, and the control transformer was only rated for 800 mA…yeah.)
The relay coil is rated 115V and 200 mA, so that’s what drives the requirements for the selector switch contacts. I do plan on wiring this with 14-gauge wire so screw terminals or spade terminals would be ideal. It will be mounted in the existing control cabinet; I’d like to put it where I started mounting the BACO switch, which is a 22mm diameter hole with about 76mm clear space behind the mounting cover (maybe a little bit more, but then you’re starting to get close to one of the 460V contactors). Cycle requirements are minimal; I’d be surprised if this switch has over 100 cycles in any given calendar year. Environment is industrial but not wet or hazardous; I’d prefer rugged but there’s no need to make it liquid-tight or seal the terminals.
I did use the Digi-Key lookup tool but there’s such an embarrassment of options that I couldn’t filter it down to something which looked likely. If anyone can give me a good recommendation, I’m all ears. Note that this is a one-off project so I need something available now in single unit quantities. Thanks In Advance for any helpful replies.
Eric, I am looking into this for you but before I offer anything I want to be sure I understand this correctly. If were to sum up your request it would be for a selector switch that would allow for four or five selection options. the first three would each be for a pump, I am confused regarding the 4th option. would all three be set to run when this option is selected?
Anyway, bottom line, we are are selecting from four 115V options with an 800mA current draw for each option, and there needs to be a fifth off position.
This would be a 4PST or 5PST.
Eric, assuming that I understand what you are looking for, these results may help you.
Click this link to see the first set of options
These are Selector Switches. You will see that the best I can find here are OFF,ON,ON,ON and ON,ON,ON options.
Of these, this looks to be the most promising.
| MFR PART # |
700-A-BL |
| DIGI-KEY PART # |
432-1260-ND |
| MANUFACTURER |
Carling Technologies |
| DESCRIPTION |
Selector Switch 4 Position SP3T 4A (AC), 1A (DC) 125 V Panel Mount |
| DATASHEET |
Click Here |
I also found some possible options in the Rotary Switches category.
Click here to see those options
Of this, I thought this looked to be the most promising:
| MFR PART # |
44A30-01-1-06N |
| DIGI-KEY PART # |
GH7614-ND |
| MANUFACTURER |
Grayhill Inc. |
| DESCRIPTION |
Rotary Switch 6 Position SP6T 1A (AC/DC) 115 VAC Panel Mount |
| DATASHEET |
Click Here |
We also have knob options for this available. The shaft on the part above is 1/4" in diameter and flatted. Here is a link to options that will fit that shaft and have a set screw.
Knob Options
Here is one I found promising.
| MFR PART # |
PKD70B1/4 |
| DIGI-KEY PART # |
450-1731-ND |
| MANUFACTURER |
TE Connectivity ALCOSWITCH Switches |
| DESCRIPTION |
Knurled, Straight Knob 0.250" (6.35mm) Shaft with Arrow on Skirt Plastic with Aluminum Skirt Black, Natural |
| DATASHEET |
Click Here |
I do hope this is helpful!
Aaron, thanks for the info. I’m leaning towards the Omron Automation A165S-A3M-2 selector; I can use it in conjunction with the BACO switch on hand…the BACO as an “H-O-A” master control, and the Omron to select which feed pump activates the relay when in automatic.
Does Digi-Key carry a custom (or printable) legend plate suitable for use with this switch? I’d like for it to look good as well as function better.
I’ve created a quote (XXXXXXXX) for this part, but every time I tried to submit it I get the message that a technical error has occurred where I was expecting to be able to input shipping instructions, etc. I also get the error message when I try to verify that the proper part is in the quote. I’ve used two separate browsers (Firefox and MS Edge). Any suggestions, or is there a telephone number I can call?
Eric,
I have been looking into your request for a Legend that could possibly work with the switch you have chosen. While I have not been able to find a stocking supplier recommended option, I did find somethings that may be of interest. Please look at the following.
| MFR PART # |
HWAM-301 |
| DIGI-KEY PART # |
1885-2040-ND |
| MANUFACTURER |
IDEC |
| DESCRIPTION |
Legend Plate |
| DATASHEET |
Click Here |
| MFR PART # |
2LP219 |
| DIGI-KEY PART # |
1920-1690-ND |
| MANUFACTURER |
Altech Corporation |
| DESCRIPTION |
Legend Plate |
| DATASHEET |
Click Here |
| MFR PART # |
GSC0T203 |
| DIGI-KEY PART # |
MGR1552-ND |
| MANUFACTURER |
Storm Interface |
| DESCRIPTION |
Legend Set C |
| DATASHEET |
Click Here |
| MFR PART # |
87AC2046 |
| DIGI-KEY PART # |
GH5024-ND |
| MANUFACTURER |
Grayhill Inc. |
| DESCRIPTION |
Legend Sheet |
| DATASHEET |
Click Here |
I hope this helps!
Eric, I have spoken with with our quotes department and you can expect to hear from someone via email regarding your issue soon.
Eric, I looked at the quote # XXXXXXXX, and the part number listed on there is Z1365-ND. If you have questions about the quote, or want to order, you can contact our Sales Department at 1-800-344-4539.
Part ordered. As far as a legend plate, I was looking at something similar to the first two items you mentioned; however, those were for 22mm devices and the selector switch I found has a 16mm circular mounting hole. Guess it’s time to break out the Dymo labeler…
Eric, I do apologize as still had it in my head that you were using a 22mm device. I went back to see what else there was and for some reason I am not seeing much for the 16mm size. You may be right, the Dymo labeler might be the best solution.
If you find that you have some time to browse you could certainly take a moment to look through the full results of my search here.
Search Results
I wish you luck in your project and I hope this helps!
