Tac 20 totally wierd

Got a Tac 20, I have the IMS tool. That being said, this unit is absolutely acting wired. Safety string "safe" on Ims and doors seem to check out ok. Can't get it to run on Mach. Room inspec. Nor cartop inspection. MCC1 is active, can't get MCC2 or MCC3 to go active to initiate a run. Jumped out the run start on the soft start term 4- term 2. Motor starts, but no MUTS relay action. Put a call in from IMS and I get start sequence and moving on IMS. Unit times out with service code 47, low oil.... This is one of the craziest thingsmI have ever seen...HELP Please

Not knowing much about the run circuit, but knowing all too well the Siemens starter fails often due to some $1.50 cent component burning out, is the starter display active? If the answer is no, and you have 120 volts at terminals 1&3, the starter control board is shot. That's all I got for ya right now.

Sounds about right, but on the tac 20 when the system has a fault your control pwr for siemens starter goes low. So to really check the starter put 120 vac to your control pwr term to see if you have a dead starter. Also the up to speed contact on the starter is known to fail often.

sounds like a mother board problem.

muts relay must be picked up to initiate the next run. When soft start drops off line, muts contact makes up and allows muts relay to pick and tell the controller that the soft start is not still running. If this doesnt happen, you dont run again. check for continuity across the motor up to speed (muts) contacts on the soft start. If you dont have continuity, you have a bad soft start.

If your MUTS relay in the control is not picking when you start the pump motor check terminal 6 on the soft start for 120VAC. If you do not see the expected voltage go to terminal 5. If there is 120VAC at 5 you have a bad up to speed relay on the soft start board. The prints I am looking at shows this circuit on sheet 12 of 24, Motor Control. This is all assuming, as elmcannic said, the soft start is turned on and you have a display.
I repair the most common Seimens 72G problems for the company I work for and majority of the time I've been able to just solder a new relay on the board. With a soldering iron and desoldering tool this can be done easily. Sometimes there is another problem with the board and a relay doesn't fix it.
You can order them from Newark or DigiKey for a few dollars. I can post a picture of the relay on Monday if you would like. The up to speed contact on the soft start stays open until the pump motor is up to speed. While the soft start is inactive you should NOT be able to read voltage(with the power on) on terminal 6 or a low continuity value between 5 & 6 with the power off. It is a NO contact.

Let us know how you make out.

Matt

Matt,

Do you also fix the shorted cap problem that causes the screen to go blank or do you send those units back to the manufacture for repair?

Yes. Scrape the cap off and replace the resistor above the diodes. You can either solder another cap across the diodes or just leave it off. I haven't had a board fail a second time with either repair in 2 years.

Hey guys& gals,
I found the problem(s) with this unit. First, the BP magnet at top floor was knocked out of position. Fixed this before the weirdness started. Second, the 2 nuts that hold the contacts for the gate switch on the door op. had fallen off, was only able to find this with IMS tool. The display always showed doors closed and OK? Don't quite understand that but whatever. Third, I had pulled the VAlve control relays out one for one and put a new one in. Well, I pulled them out again today and discovered that I had bent one of the pins on the N.C. Contact on one. Of the relays! Put it back in and Bingo, the unit took off! Sounds great, but unit went into viscosity control and would not stop. Got a bad Oil temp. Set sensor, jumped around it for now......what a bunch of strange things on a single unit......running now!! Thanks for all the help.

If you have ims make sure it's in metered logic. You don't use positive logic till you get into tac 32 stuff.....