Anyone Else Having Problems with Taco 0011 Circulator Failures?

I am still in somewhat of a "shakedown" mode on getting the bugs out of our new EKO 60 system. I just had my second primary circulator failure, after about a week of running a new replacement. The first one lasted only about 2 weeks. While I haven't pulled this one apart yet, the first one had a motor bearing failure, which was a factory defect. The second one has been in service only a week, and I just pulled it about an hour ago, when the EKO controller blew a fuse. A replacement fuse blew immediately, and I suspected the circ. Disconnecting it, with a new fuse was fine. Of course, I had just loaded it to the gills for the night. I pulled out the new wood that wasn't burning yet. I had an idle zone with an 007 circ in it, so I swapped that out with the 0011, just to be able to burn off the remaining wood. It seems to be working good enough, and is keeping the temp down to 165 or so, while the load slowly burns down.

I wouldn't normally believe two bad circulators in a row. However, only about a month ago, I had an instrument failure at our lab (my wife and I are both analytical chemists with a small business). A component (an online degasser) of the Agilent/HP system failed. No big deal. However, to the amazement of Agilent and myself, they sent me FOUR consecutive replacement instruments in a row - the fifth one finally worked. Each failed after a few days. Now this is Agilent, with a well earned reputation for top quality, and we have had similar modules work for 10 years without problems. So I guess I am willing to believe that it could be coincidence, rather than design, and that in this new age, one could get two circulators in a row to fail. After finishing up the last zone, where I can find probably one out of four copper fittings that just won't fit, and of course, with melamine in baby formula and milk in China, I could believe the possibility of such poor quality.

Anyway, not to get on a rant, but has anyone else had abnormal Taco circulator failures lately?

Thanks for the input. 2.Beans, you asked if I had an open neutral? I am running the pump directly from the EKO controller, using #14 wire, with a ground. I hooked the three wires up to the controller, and to the pump, including the bare ground, which I grounded using the green screw on the pump junction box. Should I be using a separate ground, or take some other precautions?

The pump is mounted horizontally, with the motor level, as recommended by Taco. It is on the supply side, immediately after a larger than normal (2") Spirotherm, so it shouldn't be seeing any air. The first motor failed with a bearing failure in the motor itself, so it wasn't an issue of proper water lubrication to the impeller. This second failure smells electical, and the motor was very hot, so I suspect the same. The primary piping is 1.5" black iron. The 500 gallon storage tank is less than 10' from the boiler. So the circulator shouldn't have much work to do, simply circulating through perhaps 30' total of 1.5" pipe through the tank and the boiler.

I have a temp/pressure gauge immediately prior to the pump, and most of the time, the water is only at about 170 -175, so I know the circ is not getting hotter than normal water (and the circ is rated for 230 deg of course). Despite all the advice in all the modern books, I may give in and move the circ down to the return side. I plumbed it with that in mind, so I can close the valves and break the unions, and re-locate the circ with only a few hours work. I still see no problem with where it is now, but will move it down to the boiler inlet anyway.

The only other thing in the system that makes me suspicious is the Danfoss valve, which is in the 1.5" iron return pipe, halfway between the tank and the boiler. It is connected to the supply pipe running about 2 feet above it. When cold, the water should just go through the short loop, and gradually increase flow through the storage tank. I have a 140 deg thermostat in the valve. I wonder if something could be wrong in there, causing the circulator to work too hard and overheat? The system has worked perfectly though, and charged the storage tank. I have temp gauges on the pipe leaving the tank, and after the Danfoss valve. Unless fully charged, I typically see the temp leaving the tank at perhaps 130 or so, and the temp after the Danfoss valve on its way to the boiler of 150-160, so it seems to be doing its job. I just wonder if there could be a restriction somewhere, making the circulator work harder than normal.

Or of course, it could just be two bad circulators in a row. I hope the plumbing supply place backs me up with a new circ!

Thanks for the feedback. I didn't think of it, but perhaps the circulator is not the best one. It is the size my dealer recommended. With the EKO 60, I needed to move about 250,000 BTUH, so with the normal delta T of 20, that would translate to about 25 gpm. The total head in the system, including the boiler, is low - I think I remember something like 4-6 ft of head, even with the 30+ feet of 1.5" piping, elbows, etc. I can't find the Taco pump charts, but I think the 0011 is a high head circulator.

Would it hurt though, to have a higher head circ, other than consuming more power than necessary? I would think it would just move more water than planned?

Don L wrote: "Using a Taco 011 at 1.76 amps X 120 volts = 211 watts. The EKO controller supports up to 250 watts total for both pump and fan. The fuse may be blowing because you are drawing too much power from the controller."

Don,

Thanks. Makes sense, and it is getting close to the capacity of the controller. What should I do - wire up a relay?