Outdoor Wood Furnace Info
All-Purpose OWF Discussions => Electronics => Topic started by: Scott7m on January 08, 2012, 07:15:35 PM
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I have a customer with an ncb175 that has went through 4 pumps in 1 year. 3 of which were the factory natures comfort pumps which I'm not all that crazy about and the other and latest was a wasser pump.
Every pump has the same problem, wears the bearings out.
I know it's a water issue but this is the only guy I know using antifreeze mix.
Thinking about making him upgrade to a sealed design pump.
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Scott,
Pretty sure this is way above my head...as I thought all pumps were sealed, but my questions would be this....does he have his OWB running 24/7? I discussed this issue at great lengths with some friends up here because I thought about having the pump run only when it was called for....but , I soon learned that was a quick way to wear a pump out...all the constant off and of. No different than a starter on a car. I did have mine wired to run 24/7. Just a thought, but you prolly knew this already being a dealer. :D
Lugnut
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Yea it runs non-stop as it should but it's a well water issue I'm pretty sure
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Did you take the pumps apart? Are you bleeding the air out of the screw on the end of the motor? Was the bushing at the end of the rotor shot? Do you know you can get replacement cartridges for those pumps?
I would put a dry rotor pump on it. The only thing that touches the water is the impeller and a little of the shaft on them. Should be much better on dirty water.
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I also run a antifreeze mix, 110 gal Propolene Glycol in a CB5036. No problems so far,I hope I didn't jinks myself...
Clyde
I have a customer with an ncb175 that has went through 4 pumps in 1 year. 3 of which were the factory natures comfort pumps which I'm not all that crazy about and the other and latest was a wasser pump.
Every pump has the same problem, wears the bearings out.
I know it's a water issue but this is the only guy I know using antifreeze mix.
Thinking about making him upgrade to a sealed design pump.
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Yea it runs non-stop as it should but it's a well water issue I'm pretty sure
Something I have to look forward to? I'm running well water as also. Have a back up pump should I require one, hopefully it won't go out too soon.
Lugnut
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i have been running well water for ten years (this is winter 11) i did use the oxygen scavenger chemical for the first two years but have added nothing since then except for make up water and last year i replaced my underground lines so the boiler got a fresh fill. i am still on the original taco 0011 pump (knock on wood) i did install a cartridge filter in my line (the cartridge looks like a ball of twine)
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willieG - How often do you change your filter? Do you get a lot of trash in the filter?
Thanks
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Well water is not necessarily an evil. Many wells are as good as or better than municipal water. Wells can be low in hardness and iron, two areas of concern for OWB owners, and do not have some of the baggage such as the addition of chlorine or flouride. If the well water is not causing problems in the home, it likely will not cause prblems in an OWB. If it is causing problems, there is a chance the homeowner has identified and corrected the problem. Proper boiler treatment chemicals will also minimize problems with poor water quality.
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Here are some pics of a failed pump due to dirty water.
The bushing at the end of the rotor wore and allowed the rotor to start scrapping and eventually stopped.
(http://www.rsiboilers.com/owfi/pump1.jpg)
(http://www.rsiboilers.com/owfi/pump2.jpg)
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Well water around here is horrible.. Full of iron and it usually stinks
Now as far as taking the pumps apart I personally have not but simply got replacements. As far as bleeding yea I always have the screw loosened up before it's ever plugged in and I back fill the system using an isolator flange to push the water through the house and back into the boiler to try and avoid any air lock issues and haven't had any doing this.
He also has a filtration system on the back of his stove, it made no difference in pump life. I agree that a dry rotor pump is the best way to go if I can convince him to splurge a bit.
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Just take the 4 allen bolts out and the guts slide right out. The new ones for the NC pump are about 1/3 the cost of a pump.
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willieG - How often do you change your filter? Do you get a lot of trash in the filter?
Thanks
i change the filter yearly..usually about the end of november. I like to use the old filter at the beginning of each year to catch any thing that may have acumulated over the summer when it is shut down, also i figure a new filter for the cold months is a good idea too. i have never seen any "chunks" in there yet but the filter is the color of rust so there muct be some small pieces in there i cant see. my stove is home made and made of mild steel plate and pipe
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Just take the 4 allen bolts out and the guts slide right out. The new ones for the NC pump are about 1/3 the cost of a pump.
Yea. Gotta keep a bunch of those laying around I think lol
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I went thru both pumps on mine in less than 2 month. I am using well water that has been ran thru a softener and iron filter. They sounded like a motor that had a rod knocking.
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I forgot to mention the one new pump the motor part is running about 175 degrees and the other pump is running 199 degrees, why the diffence in temp
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Did you bleed the air out of the motor end? If you don't do that they will die pretty fast.
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yep even ran them awhile then rebleeded them
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Did you open them up to see what happened to them?
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no I didnt open them cause they replaced them under warranty, but the dealer plugged the one in that quit all together and the impellor went out to the pump side so it looks like it has a bunch of endplay in it. what would be the best replacement pump brand and model. I would rather spend the money and get a good one than buy the cheap pumps and replace them all the time
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which pump is on the nc250?
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I am going with B&G PL36 pumps instead. They use a lot less power and pump more water. I have one of the NC pumps left that has a new cartridge in it and after that I won't be getting any more. I am hoping they will give me a decent discount on boilers without the pump.
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which pump is on the nc250?
They use the same pump on all models.
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200 bucks on their site. how much is a better pump?
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200 bucks on their site. how much is a better pump?
What site?
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http://water-to-air-heat-exchanger.com/water-pumps-for-wood-boilers/ (http://water-to-air-heat-exchanger.com/water-pumps-for-wood-boilers/)
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it says 4148, but at checkout it is $198.
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You can get a pl36 pump for close to the same price.
Otherwise if you want to stay with a wet rotor pump a Taco 0011 is also around the same price.
I would try to go with a pump that is American made. Bell and Gossett, Grundfos, Taco, Armstrong and a few other brands are mostly made in USA.
I prefer dry rotor pumps like the Bell and Gossett PL36 because they can handle dirty water and air better.
Also, Taco 2400-20-WB and Armstrong e7, e8, e9, etc are the same type pump but more expensive.
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I agree with RSI. Md2020 r u having trouble with yours?
I wish I could convince all my customers to go with dry rotor pumps.
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Looks like the pl36 might be a tight fit expecally when you try cramming 2 of them in there
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no problems with pump, did have a drip from threaded pipe which shorted out the blower. all good now. It was good to take it apart on a warm day; if it was cold, I would have been whining.
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I had to rewire mine to bypass the thermo cut out on trhe coldest day of the year at 1030 at night I wasn't happy
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Looks like the pl36 might be a tight fit expecally when you try cramming 2 of them in there
They aren't that much bigger. Just a little longer motor.
(https://lh6.googleusercontent.com/-YRLw5O6WfFs/T1D9u_uaIzI/AAAAAAAAAUQ/BQYUstMqIOA/s1024/20120302105900.jpg)
(https://lh4.googleusercontent.com/-CHqUSjwwDXU/T1D9mLBni6I/AAAAAAAAAT4/-g3SDFH72qo/s1024/20120302105916.jpg)
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Is the increase in flow going to hurt anything? I am running the one for the house on low and the building on medium, don't know if that will cause backpressure that would be hard on the pumps or not.
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If you are only running it on low you might want to consider a Grundfos 15-58. They are only around $100. The pumps that come on the NC boilers appear to be Grundfos knockoffs but there isn't a Grundfos with the same specs as the NC pump.
Nature's Comfort claims you will burn less wood leaving the pump on high because of the way the return water is routed it can pull more heat off that is going up the chimney.
The PL36 pumps actually seem to like being restricted. The watt usage drops and they get quieter. (less watts should mean cooler running motor)
The one I have running at my house is using about 175 watts and if I close the valve down drops to about 130 with completely restricted. I have pex-al-pex so if you have normal 1" pex a PL36 will probably use 150-160 watts.
I have heard numbers from 245 to 285 watts that the NC pumps are drawing on high speed from people that have put meters on them. The lowest I have heard on low is 205 watts. That is what made me finally decide to not get any more.
If you have a pump using 100 less watts and you are paying $0.10 per KWH you will save over $7 per month. At $40 a year the pump will pay for itself in a few years.
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I have a 200,000 btu heat exchanger in the building and the one for the house is I think 104,000. So what do you think would be
the best setting? I ran them both on high before just seems noiser.The whole system even the exchangers are 1".
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Since you have 2 pumps you will have more water flowing back into the boiler on the lower settings than one pump would on high. I would turn on the blower and then feel how much the return pipe cools on the different settings. Just grabbing the pipe will get you a good idea on the temperature.
How many feet of pex are in each loop?
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garage is 30-35 feet house is 100feet it is about 30 degree drop from inlet to outlet. I am going to get one of them pl36 pumps I think just to have a spare found them for $208 shipped
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I could sell you one for $205 shipped if you want. Lol
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If its new which I believe it is its a deal. You been a big help with all my newbie question is beats buying it from ebay
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Yeah brand new in sealed box. I have to buy them in batches of 5 to get good pricing so I keep them on the shelf.
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My ears are perking up about this filter, are you saying you have a filter on the supply or return line from them boiler? If so it sounds like a nice project for me, I am using well water , when I check the level it seems pretty clean but last time there was something floating in it
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Way back (8 or 9 years ago.. lol) when I bought my first outdoor boiler they made me buy a filter or they would void the warranty. (Pacific Western brand, turned out the warranty was no good anyway)
They sold me a Rusco spin down filter. It was only a 3/4" so restricted the flow a little. I have had it bypassing for the last couple because it seemed to be restricting the flow a lot more and cleaning the mesh filter didn't seem to help much anymore.
I didn't know what was the correct replacement filter so never replaced it but I just set up an account at a new supplier that carries them so will order one next time I get stuff from them. They also have 1-1/4" models.
They are pretty expensive though. I think I paid close to $200 when I got mine but if I decide to start selling them the 1-1/4" will probably be around $150 and 3/4" $20 or $30 less.
Depending on what you are trying to catch, you might be better off with a $25 Y strainer.
I used to always recommend Y strainers to everyone with plate heat exchangers but then started running into problems with people not maintaining them and found it was less trouble to leave them off.
If you are going to keep it clean it probably is a good thing to have.
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After having so many failures with the same pump, I would definitely look for other options. Taco and Grundfos are all that is used around here until we get into commercial or industrial and even then its still Taco mostly, no one likes call backs. What is the pH of the water? Doesn't matter what speed or size pump you have the head will determine how much gpm you will flow. To large a pump and you could create cavitation and burn the pump up. 10 gpm will supply 100,000 btu/hr at 180*. Wet rotor or dry, improper application/size will always use more electricity, especially on cheaper pumps. A 007 on 1 1/4" P-A-P pipe will flow more gpm and use less electricty than say a 0012 or 0014 on a 1" pex header. It always takes more money in the begining to save money long term. Pumping glycol takes 10-30% more energy and flows 10%+ less gpm compared to water. Any of those pumps should not have any worn parts in that short of time ( 3 in 1 year) without defects or highly corrosive liquids present, which glycol is, in open systems to brass and copper. Todays pumps are much better than those of 20 years ago, so cycling them is fine, they don't have to run constantly if they are sized correctly, this is usually a sign of undersized pipe or pump. If you add a filter, especially those spin off types, make sure you calculate the head loss as many will require 2 sizes larger pump. There are some with very low head loss , but at a considerable price. Good luck on finding the root cause.....