Taco 011 pump will not start cold after several days - 2nd time this season

[rwh442]

This is the second time this season that my Taco 011 pump would not start after being shut off for several days. We have had a warm spell and my boiler has been off for several days. Water temperature was around 65 degrees, went to start the pump - just hums at me. This is exactly what it did about two weeks ago during another startup after a warm spell. I have only shut the pump off these two times since this season's startup in November. I kept trying and eventually it turned over slowly than ramped up to operating speed.

Do these things get "tight" after a while? I thought they were wet lubricated? Does a high head system cause problems starting? I have measured the flow rate around 5.5 GPM, about 25 feet of head according to Taco's specs. Any experience with this issue?

 

[Fred61]

You must have some rust or some other contamination in there. I had one zone in my previous house that did this a couple times. Took it off and tried to free up the impeller with a probe. Actually this is the main reason I believe in boiler water additives. Not for water jacket rust prevention but for circulator lubrication. Just had a conversation with another wood boiler owner just last week. He picked some purple stuff up at a local plumbing supply that claimed to be a lubricant.

 

[Fred61]

Forgot to ask you how you have it mounted. Do you have the motor vertical ( Up or down) or horizontal (Motor left or right)? Motor should be horizontal. If not you will get drag on the bearing. I think the weight of the armature overcomes the bearing thrust.

 

[rwh442]

Fred,

I do have a water treatment additive. Also, since I knew the pump acted frozen up the first time, this last time I waited for a few hours and it started right up. Tried it about half a dozen times after that at hour intervals and it was fine. The pump motor housing was almost completely cooled off. Then I come back several days later and it acted froze up again the same as the first time. Do you still think it is rust?

 

[rwh442]

Fred,

The motor and shaft are horizontal.

 

[jebatty]

System head should have no effect on start-up. BTW, 25' of head = about 8 gpm on the Taco 011 flow chart. Each gpm = 10000 btuh at delta-T = 20.

 

[Fred61]

Fred,

I do have a water treatment additive. Also, since I knew the pump acted frozen up the first time, this last time I waited for a few hours and it started right up. Tried it about half a dozen times after that at hour intervals and it was fine. The pump motor housing was almost completely cooled off. Then I come back several days later and it acted froze up again the same as the first time. Do you still think it is rust?

Tough to tell from here. My limited experience with these things is either they are stalled because of some contaminate in the impeller or they are burned out. I guess if I were experiencing this, I would not cycle the switch, but remove the pump and carefully rotate the impeller and try to observe whether it appears stuck or moves freely. If it is stuck, you've only got one chance to notice this so probe carefully. These things don't have much starting torque.

 

[rwh442]

Thanks for the replies. I will take the pump apart after it sits idle for a few days here soon and check the impeller movement and/or rust.

 

[slowzuki]

Most newer pump controllers have a pump exercise feature built in to spin them up for a few seconds on regular intervals to avoid your problem. That tells me it is common.

 

[in hot water]

Grundfos has a small device that "tickles" the motor to help perevent froxen pumps. I've not had problems with Grundfos sticking since they upped the starting torque and added that electronic device to vibrate the rotor.

hr

 

[rwh442]

The boiler has been down for almost a week due to warmer weather but tonight I tried to start it up and the Taco 011 would not run again - just hum as before. This time, after tapping it lightly with my mallet as before (typical starting technique), it never did turn over. Since I'm basically done with wood heat for the winter I decided to take the cartridge/impeller out and check it. The impeller was very tight and would not turn. I shook it and it had some water in the cartridge and some black liquid came out of it also. The water that was in my lines when I took the cartridge out was very clear and clean.

I basically kept messing with it until it turned freely. At some points during the rotation it did not sound quite so good - a little rocky. So it looks like I will be looking for another pump or cartridge.

I put the pump back together and it started right up. Sounds/works like normal now.

Questions:

1. I would assume that water is not supposed to get into the cartridge. Is there a seal that failed? Is this common? I'm a newbie with these pumps - first year.
2. During the first flush in October of the system I used some cleaning solution (Prep solution 101?) from Cozy Heat. It was the dark color that I saw come out of the cartridge when I shook it. I'm wondering if it ate up any seals (if any)? Dunno.
3. I read a few times that it is almost as cost effective to buy the entire pump instead of just the cartridge. It looks to me that the cartridge would tend to be the only thing that would ever need replacing. The windings should last a while I would think.

Anyway, I'm a little disappointed in the Taco. Don't know if I killed it or it commited suicide. . . . .