La marzocco linea blowing steam boiler contactors

#1: Post by **leozava** » August 19th, 2013, 5:08 pm

I have a 4 group linea av and I keep blowing contactors for my steam boiler, the first time it happened I replaced it and it lasted 6 months now I'm lucky to get 2 weeks out of it. Any help would be great

#2: Post by **D'Laine** » August 19th, 2013, 7:23 pm

Something this large would potentially create a big spark, fire and smoke.

You've got a hot spot somewhere in your wiring or your boiler heater. The amp rating is stamped on the machine, as reference, an amp meter will tell you how much you are over by. Let's assume you're not using a sub-standard contactor. It should be rated for the nameplate. You give no details.
Maybe the boiler heater is fouled? A tech should trace the wires and power draw.

Good luck,

Dave

January 12th, 2015, 9:10 pm

So the contactor on my 4 group linea keep frying, I pulled the element and it looks good. It's a 3000w element and the continuity test at 16.3 which seems about right. Any suggestions???

#4: Post by **kize** » January 13th, 2015, 1:06 am

As stated you should put an amp meter on that element and check it. Better yet use the current meter at the contacts in question. That will rule out over current draw or just a subpar contactor. If you're torching contacts something is out of wack. Those things should go for years of heavy usage.

January 13th, 2015, 10:20 am

http://www.ebay.com/itm/280733343775

That's a link to the contactor I've been using

http://users.rcn.com/erics/ · #6: Post by **erics** » January 13th, 2015, 9:05 pm

I ASSUME this machine is being used in a café setting.

As a first course of action, I would simply buy the contactor (relay) either directly from La Marzocco or one of their parts distributors. As others have said, this relay should perform very satisfactorily for 18 mo or longer.

As a second course, I would have a LM tech advise on the use of an SSR(s) to accept the control signal from the existing pstat (or one having a smaller deadband) or, better yet, simply install a PID setup.

#7: Post by **gor** » January 13th, 2015, 10:58 pm

That contactor is certainly rated to do the task at hand.

If the Steam boiler is controlled via PID and not Pstat, it could be a case that the PID controller is cycling 'too many times' and thus burning out the contactor via a large number of short duration on-off signals. The contactor has got a duty cycle that you can look up with the manufacturer, and it could just be that the PID controller has turned it off and on 'that' many times in 6 months?

January 13th, 2015, 11:20 pm

I'm still running the p stat. Also, I wish I was getting 6 months out of it, 3-4 days tops. Is the element to small and taking too long to get to temp???

#9: Post by **ira** » January 15th, 2015, 1:30 pm

3 days means something is very wrong. For all practical purposes, a properly rated contactor should last almost forever. Is there any chance water is dripping on it? Still doesn't seem like that should be able to cause the problem. How many contacts? if more than one, are all of them dying or just 1 set?

Ira

February 18th, 2015, 4:45 pm

problem solved!! I installed a 40a ssr with a heatsink instead of the contactor, havent had an issue in over a month AND no more "clicking" from the contactor