Replacing Circulating Pump


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Old 12-07-09, 09:42 AM
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Replacing Circulating Pump

First off just wanted to say hi to everyone, I have being trolling around for a bit and you guys got a great community hear.

I am doing a little maintaince on my moms Super Hot MG boiler system as she has being having a few problems with it. There are two Grundfos UP 15-42F pumps in her setup and I am pretty sure one of them no longer works. It has little to no vibration coming from it and seems quieter then the other pump. It also gets very hot much hotter then the pipign right next to it.

Is there a sure fire way to test if the pump needs to be replaced?

The 14-42 is no longer manufactured and the reccomended replacement is the UPS 15-58FC will using two different types of pumps be a problem? should they both be replaced together?
The pumps are not on seperate zones.
 
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Old 12-07-09, 10:34 AM
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If you have a voltmeter and know how to use it, see if you're gettilng 120VAC to the pump in question. If not, then there is an electrical or control problem.

Are the two pumps in parallel? I'm having a little trouble visualizing your setup. Please take photos, post on a freebie hosting site, and link here.
 
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Old 12-07-09, 02:49 PM
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You can have 2 different circs in series or parallel. The circs don't care.

Estimating the flow thru the combination will be more troublesome, but you should have more flow that with the 15-42.

Maybe post some pics so we can see what you got going on.

Your Superhot may have primary / scondary piping.
 
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Old 12-07-09, 04:34 PM
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The pumps are in series but if I understand correctly it does not make a difference anyways.

Unfortunately my voltmetre is back in Vancouver and although they are cheap I am cheaper. I will try to borrow one off a neighbour or friend.

I will get some photos up or maybe create a schematic; whoever installed the boiler did a messy job.

So how important is the rate of flow. The 15-58 has 3 speed settings on it will I need to make some calculations to find the best setting? or will the difference be negligible?
 
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Old 12-07-09, 04:48 PM
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Originally Posted by YakamoXIII View Post
The pumps are in series but if I understand correctly it does not make a difference anyways.
I think TOheating said the pumps "don't care" if they are in series - i.e., the pumps themselves will be fine either way. That's not quite the same as saying it doesn't make any difference to system performance.

What exactly was the problem that your mother's system was experiencing?

In series, pumps will increase the total head. But I wonder why there are two pumps in series? Maybe the original pump didn't produce enough head? Ideally, just have one pump that is suited for the application.

We really need your pictures posted here.
 
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Old 12-07-09, 08:12 PM
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Hey I got a few pictures of the set up. As I said it is a bit messy I tried to label the pipes
red = output
yellow = bypass
blue = return

Pictures by yagamota - Photobucket

Hopefully it helps a bit. I will be replacing the first pump in the series as it no longer seems to work. Is the new pump with the higher flowrate going to change things a lot?

IMPORTANT! (maybe)
Now it has come to my attention that the whole setup might have a problem, both of the bypass pipes are connected in-between the 2nd pump and the return on the boiler. From what I understand should the pump not be on the other side of the bypass lines. As in right now I have
===(pump)===(bypass)===(return on boiler)
but it should be
===(bypass) ===(pump)===(return on boiler)

I hope this is clear, we are going to have someone come and look at it ASAP. I was also thinking of making this a new post if this turns out to be actually a big problem.

Any light that could be shed on the situation is much appreciated.
 
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Old 12-08-09, 03:00 PM
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Keep the same thread for continuity sake...

Wow... I can't help but think that this was somebody's attempt at a primary/secondary setup...

On the supply line, there is a gray aquastat. What does that control?

Just a little past that, there is a round gray thing that looks as though a little further down the pipe it has a temp sensor... what is that? (closeups?)
 
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Old 12-08-09, 07:38 PM
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Pictures by yagamota - Photobucket

Posted some close-ups for everyones viewing pleasure.

The grey aquastat is kind of a joke, I was playing around with it trying to figure out what it did, finally I traced the wires and found it is connected to absolutly nothing! Props to the installer.

The round thing is apparently a flow control valve that as you guessed NJ has a temperature sensor. From what I understand it opens and closes depending on the temperature of the water compared to your chosen setting. I don't quite understand how it works or its significance, I usually set it to full throttle.

We had a technician come in an look at it and got all worked up about the drain valve right off the supply was leaking a small amount of fluid (a drop a day). He claimed it wasnt supposed to do this and that it was a sign of a serious problem. He also stated that the 2nd circ pump was in the wrong place and needed to be moved and that the other circ needed to bechanged right away and threw out a quote of 1500 to fix everything.

Talked to another tech and he was not concerned at all about one of the circs not working stating that a system such as this really only needs one pump anyways. The small about of discharge from the drainage valve did not seem to phase him either. He suggested to tear the whole setup apart and install a much cleaner wall panel. I agreed with that but not the price, 3000 bones. Oh and he did not even see a need for the two bypass lines (back flow) stating that smaller residential units usually don't need one.

Now I am more confused the ever...
Is the setup actually wrong does the circ need to be moved?
What does a small amount of discharge actually signify?
Should I just close off both of the bypass lines (backflow)?
Is one pump enough? can I calculate this based on the squarefootage (to estimate length of hose)?

Getting another tech to come in tomorrow can't wait to see what he has to say.

Thanks for all your help guys it is much appreciated.
 
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Old 12-08-09, 10:17 PM
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First, let me say this: BEWARE! Before you hire someone to work on that system, make sure that they can indicate to you that they at least have some rudimetary understanding of the thought process (although obviously a bit misguided) that went into it's design!

Looking over the system, and sketching up a crude diagram of what I think it is, tells me that indeed, someone put this together to do the following:

The pump on the SUPPLY side of the boiler is pumping around the loop through the FIRST bypass, the one AHEAD of the temperature device.

The pump on the RETURN side is intended to circulate water around the SYSTEM, using the SECOND bypass.

The temperature device is intended to control the temperature of the water circulating in the SYSTEM, which appears to be IN FLOOR RADIANT TUBING. Please CONFIRM the type of heat emitters in the home, because this is very important. Does the entire home have IN FLOOR RADIANT, or is there a combination of that and baseboards?

With radiant tubing, the water into the floor should be no higher than around 120 or so, and that temp device is intended to control that. That's why there are thermometers on the pipes.

So, here's the scenario... when there is a heat call, the system fires up. The BOILER LOOP is allowed to get HOTTER than the SYSTEM LOOP in order that the boiler does not get subjected to massive amounts of cool return water, causing the flue gases to condense, and ruin the boiler in short order.

The temperature device is intended to regulate the amount of HOT boiler loop water that gets INJECTED into the SYSTEM LOOP. A 'mixing valve' ... sort of ... at least an apparently misguided attempt at one.

got all worked up about the drain valve right off the supply was leaking a small amount of fluid (a drop a day). He claimed it wasnt supposed to do this and that it was a sign of a serious problem.
Show this guy the door. Don't let him back in. If you have a leaking drain valve, all you need to do is either replace the leaking valve, or go to Home Depot and get a brass hose cap and screw it on until you replace the valve. Everything else he said is crap. He doesn't understand, and doesn't care to, all he wants is to freak you into giving him money for something that probably won't work when he leaves.

The small about of discharge from the drainage valve did not seem to phase him either. He suggested to tear the whole setup apart and install a much cleaner wall panel. I agreed with that but not the price, 3000 bones. Oh and he did not even see a need for the two bypass lines (back flow) stating that smaller residential units usually don't need one.
This fellow was a little more reputable, but it is clear that he still did not understand what you have, and the need for proper temperature control for in floor radiant, AND boiler protection from condensation.

Let's hope the third guy knows what he's talking about.

more...
 
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Old 12-08-09, 10:26 PM
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So the gray aquastat isn't connected to anything? There is a piece of armored cable coming out of it on the top I believe? And that is just hanging there not connected to anything? Are you sure that it's not running one of the pumps?

If you follow the AC power from each of the pumps back to where it comes from... where does it come from? In other words, what is powering the pumps up? Are they both coming from the same source?

Here's what I would suggest at this point... it's freekin' cold... money doesn't grow on trees... this system has obviously performed to some degree of success for several years?... why alla sudden does it need to be ripped out and redone in the middle of the winter, to the tune of multi-K $$$ ?

Figure out why or even IF that pump isn't running, and FIX THAT... just get it back to where it will heat the home for the winter, and deal with thinking about having it properly piped up in the warmer weather...
 
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Old 12-08-09, 10:29 PM
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replacement is the UPS 15-58FC will using two different types of pumps be a problem? should they both be replaced together?
Which one of the two pumps do you believe is not working?

Answers to above: NO, and NO.
 
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Old 12-08-09, 10:52 PM
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As an aid to help all understand what this system is supposed to be doing, I've knocked together a very basic diagram:



This appears to be a misguided attempt at some kind of primary/secondary piping scheme with injection mixing to control water temp for the in floor radiant tubing.

Oddly enough, it probably DOES actually work to some degree.
 
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Old 12-09-09, 12:47 PM
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Wooo! alright thanks for the spiel NJ. Have a much better idea of what is going on now.

The whole system is in floor radient tubing, there are NO baseboards.

The pump on the supply line is the one that is not working.

The grey aquastat does appear to be connected but as I said i traced the wires and they do enter the boiler however they are terminated inside the boiler. So it appears to be installed until you actually take a real close look behind the boiler panel.

Unfortunatly right now the system is operating a little weird (maybe because of the shot pump) both of the loops (bypass lines) are feeding the water from the return to the supply. Which means that the return water is very cold compared to the supply. Should we keep it off until we fix this problem? my mom has a standard furnace as well but it cant be off for to long as its about -15C up here and that might mean the water freezing!

My mom does remember the first loop (the one ahead of the temperature control valve) used to get quite hot. This was probably when both the pumps were working and would be right in line with NJs theory.
 
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Old 12-09-09, 03:26 PM
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I would simply replace that pump ASAP and be done with it for this winter. With that pump not running, you have little to no flow through the boiler. This means that when the boiler fires, the water coming out will still be very hot but there is not much flow through the boiler, and the returning water to the boiler is way too cold for it. It's gonna take a hurtin'...

Are all the tubing in concrete? or are some under wood floors?

Has the heat been adequate with the setup the way it is for several years at least? In other words, if it has a track record of actually working, then why mess with it?

When you have that temperature valve cranked 'wide open' have you noticed what the water temperature being supplied to the radiant tubing is ? (the gauge on the pipe?)

I can tell you that you definitely do NOT want to close either of those bypasses. System won't work for nuthin if you do that.
 
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Old 12-09-09, 03:47 PM
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See if this helps... you may or may not have the plug on the end of the motor shaft.



And even if this does work, it may or may not work for long... but most times if the pump is 'stuck' freeing it up in this way can get a longer life out of it.

It actually appears from the picture that the 'plug' is already removed? Do I see the slotted end of the motor shaft there?

What happens when these pumps don't operate over the summer is that they 'stick' and need a boot in the a55 to get going again.
 
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Old 12-09-09, 11:28 PM
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All of the tubing is in concrete the first zone supplies the basement and the second zone is for the garage.

Yes the heat has being adequate for 5 years or so now, however there has being a lot of hiccups along the way. This is the second boiler my mom has had the original only lasted 5 years and then had to be replaced. When the boiler was replaced the tech made some changes to the setup because he felt it was not originally installed properly. (pretty sure he was right as the original technician was the one who created the messy install in the first place.)

The temperature supplied to the radiant tubing usually holds right around 110C-120C however I notice that when the boiler shuts off after firing the temperature will spike to about 140C or even 150C.

The plug is still on the circ pump I will give your suggestion a try tomorrow and see what happens.

Thanks again
 
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Old 12-10-09, 04:58 AM
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How did the first boiler fail?

What markings, brand are on the tubing?
 
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Old 12-10-09, 11:50 AM
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The last boiler from what my mom remembers died out because the water in the return was to cold which lead to condensing. There was a lot of banging and groaning back then.
When the second (current) boiler was installed the setup was changed which supposedly fixed the problem.

The tubing is kitec made by ipex. Any opinions on this brand? what kind of temperature can this tubing take?

I wont be around to play with the pump until late this weekend so we will see what happens then. In the mean time I am going to try and track down a new one, anyone have any suggestions for a good Canadian retailer?
 
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Old 12-10-09, 03:08 PM
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The temperature supplied to the radiant tubing usually holds right around 110C-120C however I notice that when the boiler shuts off after firing the temperature will spike to about 140C or even 150C.
CELSIUS? You sure ? that's WAY too hot!

120C = 250F

You MUST mean Fahrenheit?!
 
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Old 12-14-09, 02:03 PM
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Sorry about the late reply was away for the weekend.

Woah ya you are right NJ I meant Fahrenheit my bad.

So we found someone who is going to come in and replace the whole piping system. He is going to do it for 1500$ which is a lot cheaper then what a lot of other guys have quoted. We also have a reference on this guy and he is supposed to be pretty good.

The boiler has being banging and groaning a bit lately and my mom is fed up so she just wants to have it replaced and fixed once and for all.

Ill keep you guys updated.

My mom says a big thanks to all of you.
 
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Old 12-14-09, 04:23 PM
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System has been working until pump quit, right?

I'm not highly impressed with the whole setup, but that doesn't mean that a simple pump replacement won't get it back into operation at least...

Up to you of course...

Did the guy say exactly what he was going to do for the money?
 
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Old 03-13-10, 12:19 PM
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more on circulating pump / hot water heating

I have a pretty big system with multiple zones. From the boiler there is an air scoop and then a manifold with 5 supply lines going to various air handlers each then having a return line to separate circulating pumps in the boiler room. The house was built by a heating/AC contractor in 1990 and I've lived here 6 years. Aside from replacing two circulating pumps, all has been well until a few weeks ago.

Here is the problem. I have one zone that services TWO air handlers: there are Y-valves (on both supply and return) servicing the two lines. Both air handlers are on the second floor and so about 25 feel above the boiler. When I call for heat using the thermostat at one of the air handlers, all works fine. But at the other, the relay does not trigger the circulating pump (the trigger is itself a relay; presumably installed so that either 2nd floor thermostat would turn on the circulating pump). And, in fact, when I override the relay with a jumper to turn on the circulator, hot water circulates through the one air handler where everything works, but not the other. The only think I can think of is that there is an electric valve that might be closed. But I can't find any. even opened the air handler to look but I see only the hot water pipes with fins.

At one time I thought it might be some sort of air lock but folks tell me that's impossible since the circulating pump should be able to pull the water up with no problem.

The original contractor is out of business and I'm concerned about bringing in someone who won't be able to figure out this custom built system without ripping everything apart.
 
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Old 03-13-10, 12:32 PM
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The first thing guys on here are going to ask you is........ How many pounds of presure do you have and at what temperature ?
 
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Old 03-13-10, 12:45 PM
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buzz is reading the tele-prompter!

And the fact that there is a pump means nothing in terms of an air blockage... happens all the time.

So read the gauge, get back to us on that...

Also, the part that buzz didn't tellya we would tellya, is to take a bunch of pics... set up a free account at Image hosting, free photo sharing & video sharing at Photobucket and upload the pics there... come back here and drop a link to your album. Please make sure the pics are in focus, well lighted, and large enough for old dudes to see.
 
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Old 03-15-10, 12:15 PM
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air bound

I dont see how this unit doesn't become airbound...The supply line has an air trap in the connection and the air scoop doesn't have the minimum 18" nipple connected to it.
A good install will have a pressure tap before and after a pump. This will tell you if the pump is pumping. The only ither way I think would be to amp the pump to see if its doing work.....OH...another method is to feel temperature difference when its on but that might require valving something off during testing.....
 
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Old 03-15-10, 02:48 PM
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hvac, yer not lookin' at Yakamo's pics, are ya? We never did hear the resolution to his problem.

Scroll up a few posts to JamesR ... he revived this thread with his own questions... check the dates.
 
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Old 03-15-10, 06:11 PM
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Pictures and my major puzzle

I've posted an album at Image hosting, free photo sharing & video sharing at Photobucket
Shows the boilers, manifolds, relays, airhandlers, valves.

The boilers both read 18psi and 182 degrees.

The zone in question is the first zone on the left; the others are all working -- including one that goes to the third floor. And, until perhaps 3 months ago -- the first zone worked too. I checked it when I kicked things on in October and just noticed the problem about 3 weeks ago.

Here is the real puzzle. The first zone feeds two air handlers. Its supply line splits in a Y (using shut-off valves to both handlers) and the return lines come back through a Y -- again there are valves. When the working air handler is turned on, the pump turns on and hot water circulates to it -- all is well. But the non-working air handler does not turn on the circulating pump relay and even when I force the pump on by jumping the pump relay, water does not circulate. This leads me to believe there might be some electrically controlled valve but (a) I don't know why the builder would have done that and (b) I can't find any! The circulating pump relay is turned on by a isolating relay (seen at the top on the relay board) and the failed air handler is NOT activating this relay. Got some electrical work to do to find the exact wiring.
 
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Old 06-03-10, 07:23 PM
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Resolution to the problem hot water distribution system -- it was an air lock. Turns out that the valves in the line from the boiler intended to let off air were clogged and the first path that air could travel was to the first air handler of the first zone. Apparently my source for "it can't be air locked" was simply wrong. A circulating pump simply doesn't have the strength to pull water up two stories.
 
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Old 06-03-10, 07:52 PM
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Air handlers are notorious for air blockages... like I said, happens all the time.

It's not that the pump doesn't have the power to pull/push the water. The water in a closed system is a big 'ferris wheel'. You add energy to the water, and it ALL starts moving at the same time, and the gravity pulling down on the water helps... so the only energy the pump needs to impart is that which is required to move only the GPM needed. The height of the 'ferris wheel' is irrelevant in a closed system.

But an AIR bubble on the other hand... that air bubble will not be moved... and when you've got a bubble of air in the pipe, no water will flow. Might as well stuff an empty potato chip bag in the pipe.

One of the things that a good troubleshooter will NEVER do is make an assumption that something can't be. PROVE IT, then move on.

Glad ya got it working after all that!
 
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Old 06-05-10, 08:54 PM
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postings

Some of these threads have people who just jump into a thread with total disreguard of others problems and say, " Ya, Ya, Ya...What ever, Now here's my problem...." rather than starting their own thread.... Sorry about the rant but it happens repeatedly...
 
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Old 06-06-10, 07:55 AM
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Yeah, it happens, but there's not a whole lot we can do about it except keep our peepers open... I do try to keep things straight, but it's impossible to keep it 100%...
 
 

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