Pump control panel

[mlmarcel]

First off, control wiring is not my specialty so take it easy on me if I'm missing something obvious. I got a service call for a pump control panel that services two pumps for a swimming pool overflow pit. I was told by the building maintenance (who are very competent by the way) that there was no power to the hand-off-auto switches. I checked the control x-fmr, fuses, and have power to the alternating relay, but nothing at the hand-off-auto switches. I'm out of ideas where to go from here.
Thanks in advance for your input.

 

[Cow]

Start tracing wires....

Look at the diagram/manual....

Call tech support if it's a factory manufactured control cabinet...

Lots of different ways to go about it....

 

[hurk27]

First off, control wiring is not my specialty so take it easy on me if I'm missing something obvious. I got a service call for a pump control panel that services two pumps for a swimming pool overflow pit. I was told by the building maintenance (who are very competent by the way) that there was no power to the hand-off-auto switches. I checked the control x-fmr, fuses, and have power to the alternating relay, but nothing at the hand-off-auto switches. I'm out of ideas where to go from here.
Thanks in advance for your input.

Does these pumps have motor starters with over loads? many pump control designs will have the over loads turning off an alarm relay that also drops out some of the control circuits including the starters, not like where the OL's are in series with the L2 side of a starter that we normally find, Myers pump control panels do this, make sure the OL's are reset.

Also many pump designs have seal failure and high temp relays that will do the same thing, all depends upon how complcated the controls are and back tracing to find where the break in the line is.

 

[mike7330]

Does these pumps have motor starters with over loads? many pump designs will have the ovel loads turning on an alarm relay that also shuts off some of the control circuits, Myers pump control panels do this, make sure the OL's are reset.

yes check the overload trips. and trace wiring from control transformer, check for time clocks, external switches .....

 

[mlmarcel]

Thanks for the suggestions. The control panel looks like it has a few years on it. It looks like a manufactured unit, but no brand or schematic/manual to be found. There are no starters, to my knowledge it controls only two small sump pumps. There is an alarm, but I thinks it's just an overflow alarm controlled by a float switch. I don't believe there are any ol's present. The pump contactors are breakered on the line side, and both the pumps work when the contactors are engaged manually. The control x-fmr is fed from two legs of line side of the breaker. The secondary is fused then feeds the alternating relay, and on to two hand/auto/off switches and an alarm silence button. I have to head back out there tomorrow and really tear into this thing, but it seems like a pretty simple set of controls, which is why I was wondering if there was something obvious I was missing.

 

[kwired]

This is going to sound silly - did you check for voltage on the control transformer output?

When checking for power at the control switches voltage was measured from common terminal to what? If control transformer is not grounded you need to test directly to L2 or you will not read anything to ground unless something is unintentionally grounded.

Next look for limits or other controls that are open either by malfunction or because they are designed to open for a specific condition. Some machines have switches on inspection or access doors that if door is not closed the control power is interrupted and machine doesn't run, may not be your case but something to think about.

 

[mbeatty]

Thanks for the suggestions. The control panel looks like it has a few years on it. It looks like a manufactured unit, but no brand or schematic/manual to be found. There are no starters, to my knowledge it controls only two small sump pumps. There is an alarm, but I thinks it's just an overflow alarm controlled by a float switch. I don't believe there are any ol's present. The pump contactors are breakered on the line side, and both the pumps work when the contactors are engaged manually. The control x-fmr is fed from two legs of line side of the breaker. The secondary is fused then feeds the alternating relay, and on to two hand/auto/off switches and an alarm silence button. I have to head back out there tomorrow and really tear into this thing, but it seems like a pretty simple set of controls, which is why I was wondering if there was something obvious I was missing.

Might check the float switch to see if it is stuck.
Mark

 

[don_resqcapt19]

How did you check voltage at the HOAs? If you checked to ground, are you sure the secondary of the CPT is grounded?

 

[tom baker]

Sounds like this is 120V control and the assumption is the secondary of the CPT is grounded (look for a green wire connected to the white wire on the X2 side0
Take one meter lead clip it to ground or a X2 (neutral)
Take the other lead and start at the transformer X1 hot. work you way thru the circuit checking for 120v. When you loose the 120 V you have found your problem

Then write down the mfg, model, serial number of the control panel, call or email for a wiring diagram. Put the wiring diagram in the control panel