Expected life of a Circulator?

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Old 12-27-08, 04:23 PM
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Expected life of a Circulator?

Hello and happy holidays to everyone.

My parents have a Weil McClain boiler with one steam zone and two hot water loops. The hot water loops use, 3/4 inch piping, 180 degree set point, and two zone valves with a single circulator pump, the pump is on the "cool" side of the boiler. The steam zone was original to the house, with the two hot water loops added on when the system was converted from oil to gas

In the fifteen or so years they have had the system; they have replaced the hot water Circulator at about five times. At the moment, they have a TACO 07-F5, but have also had a B&G "little red" in the past.

This weekend, like in the past, the 07-F5 pump has begun to make a "knocking" noise which from past experience indicates itís not long for this world. Five pumps in fifteen years seems absurd, but I may be wrong. There is even heat everywhere, and the zone valves have "end switches" which in turn activate the pump relay once opened, so itís not like the pump is fighting a stuck zone valve.

My only thought is the steam zone is introducing "junk" into the water supply which the pump then has to deal with. The system is drained and refilled once a year, and the water is quite rusty.

If replacing a pump every three years is to be expected, then fine. Other than that, any suggestions as to what is causing this problem?

Thank you everyone for your help.
 
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Old 12-27-08, 05:05 PM
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I can't quite visualize how you have a steam zone and hot water zones supplied by a single boiler. Can you explain how the system is piped up?

I don't think circulators have a specified life, but in hot-water service, they should be expected to last a lot longer than three years.
Doug
 
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Old 12-27-08, 05:35 PM
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I'll take a few pictures and post them tomorrow. I didn't install the boiler myself - (a licensed plumber did so - and then the unit was inspected)

However, after your reaction, I checked a few places and the impression I'm getting is the unit (weil mclain EG series) is installed using BOTH water and steam when its designed to do only one or the other (insert stomach sinking feeling)

With any luck pictures will help tomorrow.
 
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Old 12-27-08, 05:54 PM
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I Have a few theories on this one.

# 1 - When using the boiler for steam, a lot of oxygen is constantly being replenished into the system as this is not a closed system.

I think a bronze pump will help out here

# 2 - Typically, when using hot water only boilers, you not only have a closed system but the temperature is usually never above 200*, whereas a steam system can go to 212* with an open system so it boils easily. If your system is circulating theses higher temps, this could be contributing to the breakdown of the circ. pumps.

My advice is to go to Taco.com or B&G.com , etc. and explain your problem to a technical adviser there and see what they say.

I would be interested in knowing what the outcome is, if you would not mind posting it here.


I could do this for you, but you will be able to answer any questions to the service tech should he/she have any, better than I would without knowing the system.
 
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Old 12-27-08, 06:02 PM
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Steam and water can be combined in a single boiler. It takes some special piping though and I think the water part cannot be higher than the boiler itself.

I would like to see how it was done also.
 
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Old 12-27-08, 06:31 PM
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Maybe it's running as a steam boiler, with an indirect water heater for the hot-water zones? If that were the case, then the steam system would be separated from the hot-water system, right?

I guess we need to wait for more info here.
Doug
 
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Old 12-27-08, 06:42 PM
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No, it's not really separated any more that the indirect would be on a hot water system.

The hot water must run under 0psi and that is why the heat from water must be at boiler level or lower. It is piped in with some check valves. I have worked on a few but I do not remember ever installing any
 
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Old 12-27-08, 06:47 PM
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There are certainly ways of piping a hot water loop off a steam boiler... and Mark is correct about the bronze pump ... they are exceedingly more costly than the cast iron ones, but will live a long happy life in spite of all the oxygen in the water... that's the killer. In fact, any ferrous item in the loop will be subject to corrosion... and that is the exact reason those pumps are failing so often.

I believe there is a paper over at B&G that explains the do's and don'ts for piping hot water from a steam boiler.

[found it ... not a ton of info, but lotsa good info none the less]

http://www.bellgossett.com/Press/Cou...intJun04-B.pdf

I also believe that a steam boiler should be 'blown down' periodically, and that a once a year drain/refill may not be enough... but you steam-heads know more about that than I do!
 

Last edited by NJT; 12-27-08 at 07:11 PM.
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Old 12-27-08, 07:15 PM
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You need a 007-BF5, which is bronze (and is not cheap -- around $200). But it'll last a good long time. Probably longer than the boiler.

As long as the supply and return of the hot water loops are below the boiler water line, you can run the piping anywhere in the building you want. The boiler typically has tappings below the water line for just this purpose.

Actually, I'm amazed you get 3 years per cast iron pump.

You might also pick up a copy of "We Got Steam Heat" by Dan Holohan. A very readable guide to steam heating for the homeowner.

We Got Steam Heat
 
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Old 12-28-08, 04:25 AM
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As stated earlier you can pipe anywhere providing it is not more than 30ft above the boiler. that is the maximum vertical distance. A few common mistakes made when piping a hot water loop off of a steam boiler is the bypass around the boiler. This drops the temperature some. If the pipe are going up, each 28" looses 1 psi. Where does the PSI come from? The circulator will add it to the system so it must pump away from the boiler. The boiler becomes the expansion tank.
When the circulator is installed drop it lower than the supply tapping. We must at all cost keep the steam from entering the circulator.
A good Y-strainer is also a good idea.
Also as stated earlier a bronze circulator.
The supply tapping should always come off higher in the boiler under the water level. It is not a good practice to supply and return the bottom of the boiler.
See link
http://www.comfort-calc.net/steam_indirect_piping.html
 
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Old 12-28-08, 06:26 AM
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Rbeck, that is some awesome information. I even learned a few things by reading that post. I have never seen baseboard installed above the boiler height.

Thanks, Mark

Hopefully that answers why this member is changing his circulators so often.
 
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Old 12-28-08, 05:35 PM
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Thanks for everyone's responses. As suggested, I dropped the fine folks at taco a line to see which pump they suggest - probably the Bronze one as xiphias pointed out. I'll let you know what they say.

Here are a few pictures of the setup for everyone to review in case you are interested. I'm new to photobucket, so hopefully this worked:

IMGED/WEILMCCAIN - Photobucket - Video and Image Hosting

You'll have to view them full size to see my notes. In addition to the cast iron pump, there is are no check valves nor strainers.

In addition to the bronze pump, I'm up for any suggestions for improvements. The system is simply drained and refilled once a year, and has not been "blown down" from what I can recall. The water is almost always "rust" in color.

Thanks again, everyone.
 
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Old 12-30-08, 01:54 AM
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What is that ungodly rat's nest of wires on the right side? The wiring on the left side (aquastat and?) also leaves something to be desired.

You definitely need to use a bronze (or stainless steel) pump on that system.

You also need to blow down that boiler on a regular basis during the heating season. The frequency and amount depending upon the quality of your water and the amount of water lost during operation. I would suggest that you blow down (through the bottom drain) an amount of water equal to about two inches of the gauge glass once a week if your water is of poor quality or once a month if you have high quality water. Poor quality means hard water or high amount of dissolved or suspended solids. High quality would be softened (or naturally soft) water with low amounts of dissolved and suspended solids. You don't need the water to be crystal clear but it shouldn't look any darker than strong tea.

I wrote quite a piece on steam boiler water recently so check the threads in the past 30 days that have to do with steam systems.
 
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Old 12-30-08, 07:22 AM
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I found your earlier posts, furd, and I'll follow your suggestions. Thanks for the tips.

Yes, the low voltage wiring was sloppy. On the right hand side its the zone valve wires from the thermostats, passing through the zone valves then back over to the others side (left side) to the relay box for the circulator. The transformer is hanging there on a 1900 box on the emergency switch as well. Most of it could have been cleaned up with a simple taco zone control box.

And now a somewhat sensitive question, since generally people don't like to comment or dismiss others work. In my opinion, the professional who installed this should have been aware that a bronze pump was needed when the system was first put in place - if not, then after the second time it failed - not five pumps later. On the other hand, I'm getting the impression that steam systems are not well understood.

With this being said, is it time to get a new plumber to service the system?
 
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Old 12-30-08, 11:54 AM
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I am going to disagree (as usual) with some of the earlier info. This has a probe low water cut off therefor blow down is not required on residential boilers. The amount of iron vs water volume it will not require a blow down.
If the water is hard the last thing you want to do is add a lot of minerals to bake onto the bottom of the heat exchanger. If the water is soft you do not want to add much water by blowing down as the biggest problem with cast iron is chlorides which is salt. There was a pocket in NJ where many steam boilers were failing and it was an area with hard water. Many water softeners. The problem was determined to be the soft water causing chloride corrosion. A residential stem boiler should feed very little water a month.
I would add a water meter (inexpensive) and determine how much water is being added a month. If it is more than about 5 - 6 gallons find the problem. The more fresh water is added the shorter the life of the boiler and the higher the fuel bills. Water will get out of the system from steam or water leaks. Check all the vents, valves and pipe joints for steam leaks. Check all the return s for water leaks. Are there pipe going under the floor? Is there steam coming from the chimney.
This boiler wiring is not only bad so is the piping. Never use copper for steam, it leaches the copper from the pipe and it ends up in the boiler causing galvanic reaction. See link below for proper near boiler piping.
My sister has an old Victorian home with a steam system. I installed a Hydrolevel VXT-120 with a built in water meter. In the last 6 years of operation she only feed 42 gallons of water. Her husband writes it down every summer and compares the years so he knows when there is a problem starting with steam or water leaks.
Steam Piping Tutorial
http://www.comfort-calc.net/Steam_Piping_Donts.html
 
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Old 12-30-08, 01:51 PM
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ALL steam systems lose water under normal operation and therefore require that fresh water be added periodically. This
WILL result in the suspended and dissolved solids increasing. Blow down reduces these solids and IS required. The amount and frequency of blowdown is dependent upon the quality and quantity of water lost under normal operation.

I will agree with Rbeck that excessive blow down is wasteful and that having a water meter on the make up water is an excellent idea.
 
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Old 01-04-09, 08:56 AM
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Same Issues

IMGED I feel your pain. I have a steam system with two hot water loops (Burnham boiler) and I've been replacing the circulator (Taco 007) every couple years. I did not know about the brass option so thanks to the other posters for the tip.

I'm pretty handy but have always hired the plumber to install the new circulator.

Does anyone know how to install the circulator? The big unknown for me is how to put the water back in to the two hot water loops.
 
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Old 01-04-09, 01:10 PM
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drneal

If the circulator is above the level of the loops, you should loose very little water. Some pictures of the boiler & nearby piping, including the circulator, would help.
 
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Old 01-04-09, 07:20 PM
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Circulatory changeout

I took some pictures but I'm new to the site and can't figure out how to attache them. Looks to me that the circulator is below the loop.

Try this link:

drneal_115 - Photobucket - Video and Image Hosting

Thanks for your help
 
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Old 01-05-09, 03:46 PM
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Changing circulator

I think changing the circulator is going to be the easy part. Getting the air out of the hot water loops is a whole different story. I'm going to ask a couple of others who know far more about steam than I to look at your pictures & offer their opinions.
 
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Old 01-05-09, 07:28 PM
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It looks like the rubber hose is a manual feed. Is that right. It is not easy to see from these pictures exactly how to purge. The idea is have a manual feed and valves to keep the water from going into the boiler. The manual feed and the purge valves must be on opposite sides of the boiler. You feed water into one side and purge the opposite side.
 
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Old 01-06-09, 05:47 AM
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Rubber hose is connected to manual feed line to steam boiler and the hot water heater (i just had the water heater replaced so I think the plumber left the hose there to drain the supply line to replace the heater. I actuate the yellow handled valve when the water level in the steam boiler goes too low.

Sorry about the pictures. The boiler is in a tight spot. I took some more and added them to the album.
 
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Old 01-06-09, 06:18 AM
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rbeck/Grady,

I think I've got it figured out. If I close the valve just above (exiting) the circulator then close the valve just above the front return to the boiler then I've isolated the hot water system (and the water in it). Then I'll need to drain the steam boiler to get the water level below the circulator, then changeout the circulator, fill the steam boiler and I'll be done.

What do you think?
 
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Old 01-06-09, 10:50 AM
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Sounds right as long as you don't get air in the heating loop or you will still need to purge the air.
If you need to purge the system, Hook a hose to the drain abobe the valve above the circulator and open one zone valve at a time. purging the air out of the valve above the shut-off valve on the return side. When done make sure the boiler is filled to proper level before opening the shut-off valves.
 
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Old 01-06-09, 05:33 PM
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Circulator

drneal: Here is a source for the bronze circulator. http://www.pexsupply.com/product_dtl...d=Taco&cID=291

rbeck: Thanks for the help. I wasn't sure about how to purge without flooding the steam part of the system.
 
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