Circulator Malfunction Mystery

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Old 12-10-08, 01:36 PM
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Circulator Malfunction Mystery

I have a new boiler installation with five new Taco 007 Cartridge Circulators with integrated flow control. One is for the boiler secondary circulator and the other four are for the zones.

Three of the four zones work great. The forth is giving me problems. When its zone calls for heat, the pump turns on normally and sometimes will circulate the water and other times will not. When it works normally the zone comes up to temp like it should. When it doesn't work the zone return pipe is cold and the boiler reaches it's upper temp limit and turns off while the pump keeps spinning forever until I shut it off.

I removed the new circulator, inspect it for blockages, removed, and inspected the integrated flow control valve which is a very simple device and all appeared to be fine. I reassembled and reinstalled it, purged the zone pipes until all air was removed and the water was very clear. Turned it on and it worked fine - for about a day, Then it would not circulate water again. So I again removed the pump, again checked the IFC valve, this time replaced just the circulator pump with another new one, reinstalled, and purged the lines again. Worked great - for about another day, then the same problem.

The zone pipes are not blocked, water flows freely when purging, the input manifold is a new 1 1/2" pipe and works perfectly for the other three zone on the same input, the circulator pump is getting full voltage, nothing is wrong with the relay or wiring, I can hear and feel the circulator turning. The IFC valve is new and looks perfect with nothing blocking it. The water pressure is 15psi which is correct. So why on earth won't the water circulate?

The only explanation I can think of is that this zone serves the highest (2nd) floor and that the 007 pump can't handle it. But this installation was a retrofit and the old boiler had a 007 pump for that zone and it was working fine for years. I've never used the Taco IFC valves before (always used swetcheks) so maybe that has something to do with it.

I'm at a loss to figure this out. I need someone with experience or insight to help.
 
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Old 12-10-08, 03:03 PM
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The problem has to be in the controls and relay for the pump, not the pump itself.
Doug
 
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Old 12-10-08, 05:00 PM
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Circulator or control?

The next time it gives you a problem, break out the voltmeter & check for 120 volts to the circulator. If no 120 at the circ trace it backward until you find voltage.
 
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Old 12-10-08, 05:54 PM
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I am wondering...

Do the 007IFC circulators cause more restriction than a typical 007 with a flow check valve. I have only used them on one installation so far with no problems so far, but they seemed more like some kind of check valve instead of a flow control valve?

Any thoughts on this one?
 
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Old 12-10-08, 09:12 PM
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Sounds like air to me ... being the highest zone, and a new system, and fresh water, the air slowly collects in that highest zone and eventually stops the flow.

Is there an air separator and vent installed properly?

Are there bleeders on the zone, or only purge stations at the boiler?

Every time you purge the zone, you are adding all fresh water with lots of entrained air ... so you just repeat the cycle. Take air out, add air, take air out, add air ... et cetera ad infinitum et nauseum ...
 
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Old 12-10-08, 11:01 PM
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Is this an old house? With a well? What pressure are you purging at? Sometimes a large air pocket will be hard to move at a lower pressure like 20 psi as in some well systems, especially combined with poor piping as in an old house where the building sags and creates even larger than normal air pockets. Sometimes, if a well system is not working correctly, it could be introducing air, like trooper mentioned. This can happen any time you purge, with a well or city water.
 
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Old 12-11-08, 05:01 AM
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Are you pumping away from the expansion tank?

Mark, the 007 IFC has a very, very small performance hit compared to the straight 007.
 
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Old 12-11-08, 09:42 AM
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Originally Posted by gilmorrie View Post
The problem has to be in the controls and relay for the pump, not the pump itself.
Doug
I first suspected the controls, even replaced the relay. However when it happened again I checked for voltage at the pump and read the full line voltage. Also I can feel and hear the pump running.
 
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Old 12-11-08, 09:49 AM
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Originally Posted by NJ Trooper View Post
Sounds like air to me ... being the highest zone, and a new system, and fresh water, the air slowly collects in that highest zone and eventually stops the flow.

Is there an air separator and vent installed properly?

Are there bleeders on the zone, or only purge stations at the boiler?

Every time you purge the zone, you are adding all fresh water with lots of entrained air ... so you just repeat the cycle. Take air out, add air, take air out, add air ... et cetera ad infinitum et nauseum ...
There is an air separator and vent installed stricly to mfgr specs. It works well I heard it venting when I first filled the system.

There is a bleeder on the zone at the highest point and I bled the zone until I felt all the air was out (no air being released and no gurgling).
 
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Old 12-11-08, 10:02 AM
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Originally Posted by plumbingods View Post
Is this an old house? With a well? What pressure are you purging at? Sometimes a large air pocket will be hard to move at a lower pressure like 20 psi as in some well systems, especially combined with poor piping as in an old house where the building sags and creates even larger than normal air pockets. Sometimes, if a well system is not working correctly, it could be introducing air, like trooper mentioned. This can happen any time you purge, with a well or city water.
The house is 32 years old and is fed by a municipal water system. To purge I first completely isolate the zone, open the fast fill valve until the pressure almost reaches 30 psi (the point where the Boiler Pressure Relief Valve will open) then quickly open the boiler zone return drain until the water runs clear of air bubbles. I repeat this procedure until the air is released and the return line feels very cold (the temperature of the fill water). Then I run the boiler until hot, open the highest bleeder on the zone and bleed until all air is released and the water circulates without gurgling. Then I check to ensure the return line feels very hot and the baseboards are radiating sufficient heat. I let the system run for a few days and then bleed the zone's highest bleeder again. This has always worked for me.
 
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Old 12-11-08, 10:09 AM
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Originally Posted by xiphias View Post
Are you pumping away from the expansion tank?

Mark, the 007 IFC has a very, very small performance hit compared to the straight 007.
Yes the system was designed to pump away from the tank:
 
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Old 12-11-08, 11:03 PM
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less... is that EXACTLY how you built yours?

You say you 'completely isolate the zone' ... so I'm assuming that you have valves installed on the returns?

When you do your purging, are you sure the water is actually going through the zone?

Assuming that you either have isolation flanges on the circs or some other way of closing the other zones, I would do it differently than you described.

I would close the boiler isolation valves.

Close the valves for all but the zone I'm purging.

Close the valve to the right of the air scoop, and to the left of the purge valve on the return side.

Connect hose to purge valve.

Direct hose into 5 gall bucket so you can see air bubbles.

Open purge valve and lift fast fill handle and let water run fast fill through just that zone until no more bubbles are seen.

If you aren't closing that valve between the purge and the air scoop, the water won't go through the zone, but right from the feed, past the valve and out the purge ...

Did you post pics somewhere of the new system?
I'd like to see them.
 
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Old 12-12-08, 08:53 AM
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NJ Trooper,
It's essentially how the system is piped. There are valves on the returns and the zones can be completely isolated. Here's a schematic:


To purge a zone I close every valve except the circ's isolation flanges for the zone and the zone's return valve. Then I purge just like you described except I use a clear hose (so I can see the air bubbles) directed to an outside drain. Water runs right through the zone and exits forcibly. I purge until I see and hear no more air bubbles and the zone return line is as cold as the incoming water. If a large air bubble can survive that I would be very surprised. There may be some residual air of course but not enough to stop water flow I would think.

Could the problem be possibly caused by the height of the zone? The IFC valve is a simple one way valve. It's positioned vertically. Could the weight of the column of water be keeping the valve from opening? Just a thought. I'm out of ideas as to how to fix this problem.

Trooper, I've been preparing a report to post here on on this piping system works because there was a great deal of discussion here about using the ESBE valve along with the Tekmar 260 controller. I will post pictures of the system with the report but first I have to resolve this zone issue.
 
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Old 12-12-08, 05:36 PM
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A piece of the puzzle must still be missing...

Oh yeah, I remember the ESBE/260 discussion a bit too well.

Interested to see that report!

I don't think the height of the zone has anything to do with the check valve or the pump ... that's pretty much irrelevant in a closed loop pumping system.

You said:

I close every valve
and you meant that not only do you close the valves on the zones and pumps, but you also close the valve between the air scoop and the purge valve. And also the valves to the boiler ... but wait ... if you close every valve, how is the pressure gauge working still, and why are you concerned with the relief valve?

Refresh me... just how high IS the highest zone, and what are your system pressures again?
 
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Old 12-12-08, 11:14 PM
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Trooper,
You're right about the pressure and relief valve. I only worry about the pressure when I purge the boiler not the zones, my mistake. I was only trying to make the point that I purge at about 30 psi which should be enough. I do close all the valves except the zone return and the circ flange valves.

I really find it hard to believe that there's air in the zone but since that seems to be the only potential problem I'll do another purge and post here what happens. As soon as I fix this I will write the report on the operation of the ESBE valve with the 260 and hopefully put that issue to rest. Stay tuned.
 
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Old 12-13-08, 01:08 AM
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[ Vferrano, I moved your post to a new thread, you'll get more response that way ]

If that zone is the ONLY one calling, do you still get no heat?

This is strange...
 
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Old 12-13-08, 01:21 AM
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Thank you for moving me to the appropriate location and titling my issue properly.
 
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Old 12-14-08, 10:39 AM
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Originally Posted by NJ Trooper View Post
If that zone is the ONLY one calling, do you still get no heat?

This is strange...
Yes no heat. What happens with the 260 is the the zone calls for heat but the water won't circulate due to this as of yet unresolved problem. The 260 turns the boiler on, but if no other zones are on the water does not circulate in the primary circuit. Since the 260's sensor is in this circuit and since without circulation the water temp does not rise much, the 260 keeps the boiler on. The boiler then reaches the max setting of the hydrostat and shuts off until the water cools and the hydrostat resets - ad infinitum. Waste of fuel. Also anyone thinking they don't need to keep the hydrostat in the circuit with a 260 would be in for a surprise.

After purging and repurging the problem does appear to be air in the zone. After I purge it it'll work fine for a few hours then stop working. If I purge it again, same thing. I don't know how air is getting in or why I can't get it all out. None of the other three zones have this problem and there are no leaks. I'm going to install a Taco HyVent in the highest point in the zone to see if that helps.
 
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Old 12-14-08, 11:56 AM
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anyone thinking they don't need to keep the hydrostat in the circuit with a 260 would be in for a surprise.
Since the aqua[hydro]stat generally acts as the SAFETY HIGH LIMIT control, anyone who removed that from the circuit would be in for a surprise, sooner or later... with or without a 260 on-line.

Just curious, what do you have the BOIL MIN setting at on the 260? (nothing to do with the air problem, just curious)
 
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Old 12-14-08, 08:47 PM
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Originally Posted by NJ Trooper View Post
Since the aqua[hydro]stat generally acts as the SAFETY HIGH LIMIT control, anyone who removed that from the circuit would be in for a surprise, sooner or later... with or without a 260 on-line.

Just curious, what do you have the BOIL MIN setting at on the 260? (nothing to do with the air problem, just curious)
The BOIL MIN setting is 140 degrees which is the factory setting for Fin-tube convectors.
 
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