US Elevator MP1220 losing HRV

Car intermittently goes to bottom floor then loses its HRV on power relay board. Jump on cartop, run up on inspection, and put back on normal then HRV comes back. Swapped with known good board but still getting same problem. Also shows no fault codes when using tool. Plz help me.

When you lose HRV, does the mode change to 8, test request? If it does you are getting a fault and it’s taking itself out of service. Look at Display 1 and look at the bottom 2 rows. If any of those are high, look into that fault. May be missing the vane, getting lost, or you might have a flakey up slowdown switch so it sees top and bottom open at the same time when the bottom opens.

Mag switches or IP8300 ?

“No fault code when using the tool”.
Interesting. As IDWT said, when the unit encounters that fault to send it to the bottom, there should be at the very least a number 8 in the Mode box of the tool.

What shows in that Mode box when you arrive? If no fault, it would show the letter D for automatic.
There is too much to list to describe just what might be causing your trouble.

But clipping door locks, DOL/DCL open or closed at the same time during a run. Slowdown switches verses selector inputs and the timing of those at terminal landings. Low power supply voltage can cause hick ups. There are input output cards as well as the dogtail board known as the multiplex transceiver on the car top. Good luck finding any of those.

The more information you can provide, the better we can respond to your problem.

IDWT; Do you recall the personality jumper position to cycle the car on test? This might help the guy catch his trouble. I can’t remember!

Another place we used to beef up were the direction limits and slow down switches. The cam // switch arrangement on the old US was less than desirable but if you add extra contact blocks to the bottom of the switches not only do you get better spring pressure you can parallel the contacts to double your chances of good connection. This will correct a lot of weird problems. We also would parallel the incoming power connection to the power relay board with wire as the male female connection have a tendency to loose spring tension on the female side. When ever you unplug any boards on a US you should inspect the female side to be sure none of the springs are not flattened out. Then they get hot and can melt in place making a poor connection even worse. I have seen HRV faults caused by individual hall buttons being grounded but the problem only shows up when that button is pressed. We still have about 12 or 14 of these units on service here and they will run quiet reliably but they do have their quirks. Row 4 pin 2 will let you cycle car in test mode.

Please tell us all info on PCD when you get onsite. As long as you have all vane and hoistway switches are in the proper sequence the elevator should recover. What happens if you force a lost condision will the elevator recover?

Thanx for the reply’s guys. Plug in tool again when HRV dropped and got “fault 2, mode 8, phase 2, and lvl1.” IMG_0230.jpg. Never worked on a us elevator before. Any suggestions will be greatly appreciated. Thanx

Fault 2 is just telling you that you are getting a Warning. You need to hit D - 1 - Enter. Your warnings are the bottom right row. The bit that is high is the actual fault.

Hit D-1 and enter. Bottom right row showed me a 4.

What kind of tool are you using? The bottom right row (Group 11) has 8 bits, 0-7 right to left so if bit 4 is high the fault is LVL. The car saw both level up and level down on at the same time.

I’m using a “US Elevator PCD 146/05050/000” and yes bottom right row labeled GP11 with 8 bits 0-7 right to left and bit 4 is high. And the user manual does indicate 4 being a lvl fault..
Nice!!. I’ll be checking that up slowdown switch first thing Monday morning. Thanx!

The up slowdown switch would give you a TSD warning. You’re looking for a problem with your leveling switches, vane, etc. And there’s also an input buffer board and transceiver on the car top that multiplexes those signals back to the controller.

Hey, Jboy.
The others are pointing you in the right direction. The MP1220 will only have Hall Riser Voltage is when the controller is in Mode D (normal operation).

Perhaps the car is getting lost when you come into the bottom floor. Check your LU, LD, and DZ from the PCD. Also look at DSD and TSD. It's pretty common, even when they were new, for the contacts on the limit switches to fail to make up. Banging on the TSD might solve the problem for the remainder of the elevator's life... or 15 minutes.

If that doesn't help, the next step is to go through your manual to look up the fault counters. The counters start at E750.