# LWCO doesn't shut circ's off



## Dangle72 (Dec 17, 2011)

Hi All,

I have a boiler system that I just started servicing. The problem that I have ran into is as follows:
When I test the LWCO, it is an electronic version, the boilers and all the circulators shut down. The system has a leak in the in-floor somewhere in the 12,000 square foot house. The owner doesn't want me to spend the time at this point finding the leak so we just keep adding water to the system.

The fill valve failed and the system lost pressure and water but the LWCO did not shut down the circulators or the boilers. As a result one circulator ended up dead.

I will try and post some pictures so that you can see how it is piped. There are two NTI trinity Ti 150 condensing boiler installed each with its own Grundfos UPS26-99 circulators piped into it. The system pump for the in-floor pulls the water through the in-floor tubing and then sends it back into the primary loop.

I have a theory but I am not sure if it has any validity. I am thinking that because the In-floor circulator is not pumping into the in-floor but drawing from the in-floor it is still sending enough water up to the LWCO to keep it from tripping? The in-floor circulator is a high head pump because all the in-floor tubing was run in a 3/8" black rubber tubing.

Any ideas?


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## OldSchool (Jan 30, 2010)

How high is this LWCO located...... and what size of fitting is it screwed into?????


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## Dangle72 (Dec 17, 2011)

The LWCO is tied into a 1" pipe on the horizontal instead of the vertical about 6" above the boilers. 
There is an auto air vent at the point where the LWCO connects as well.


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## Dsm (Nov 27, 2011)

Low water cutoff will only trip if the water is below the lwco. They are more designed to keep the boiler safe than they are to keep pumps safe.


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## OldSchool (Jan 30, 2010)

*The fill valve failed and the system lost pressure and water but the LWCO did not shut down the circulators or the boilers*

I don't know if this guy knows what he is doing...

LWCO does not work off pressure ... it works off of water level

So how much pressure did it lose and why didn't the boiler feed work

there must of been water still in the system or the boiler would have been dry fired and the boiler would have been cracked also....

this was the reason why I asked where was the LWCO located...

I asked what size of fitting it was installed in because if the fitting is not large enough some water will remain in tee and the LWCO will still be able to ground out.... or if the fitting like he says is on the horizontal then maybe the water is not leaving or draining from the fitting on low water allowing it to ground out....

Either way... this fellow needs some schooling .....


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## Dsm (Nov 27, 2011)

OldSchool said:


> The fill valve failed and the system lost pressure and water but the LWCO did not shut down the circulators or the boilers
> 
> I don't know if this guy knows what he is doing...
> 
> ...


LOW WATER not low pressure cutoff, agreed on the schooling. 
I've never had an instance where residual water in the tee left it possible for the LWCO to still function, interesting possibility though.


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## Miguel (Aug 10, 2009)

I've seen LWCO's get "fooled" by scaling and sludge in the piping but you say you recently tested the LWCO? Or did this test come as a result of the dry-fire incident?

If the LWCO is located 6" above the boilers then it should read fine whether installed on a horizontal or vertical section of piping but it should be setup in such a way as to avoid the scaling/sludge issue. ie: the probe should be right in the water stream*, preferably in the primary loop and setup in such a way with a blowdown cock that can simulate a low water condition when none exists, for testing. 
*(Getting the probe right in the water stream is difficult especially when installed in a 1" CxFIP off of a 1" CxC TEE.)

Exactly WHAT gets shut down in a low water situation depends on how it is wired. The whole works should be de-energized until the water level at least covers the probe.

Personally I'd like to see pics of the piping arrangement, pump nomenclature (I always like that word! lol :whistling2 for ALL pumps, etc. A control wiring schematic would be nice.

Pumping into or pumping from should have no bearing however, a high velocity pump can tend to flood a section of piping (ie: hold a column of water whether it's flowing much or not at all). How many manifolds and where are they situated? What manner of piping (size, elevation, distance) supplies these manifolds?

Tons of 3/8" rubber tubing makes me go, "hmmmm"


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## muleychaser (Feb 20, 2012)

I have looked at a system using the 3/8 rubber tubing once before. Did some digging and it was a system that came out of Europe years ago and apparently never panned out in Canada. I feel sorry for the people that have them because they are garbage.

Check the wiring first it may have been bypassed or done wrong to begin with.


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## CTs2p2 (Dec 6, 2011)

This is an old chat but....

Newer electronic lwco like safeguard 1150. You dont want to Teflon tape, pipe dope only..
This may not be his exact problem, but I don't and won't tape em...


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## Joeypipes 23 (Feb 2, 2011)

CTs2p2 said:


> This is an old chat but....
> 
> Newer electronic lwco like safeguard 1150. You dont want to Teflon tape, pipe dope only..
> This may not be his exact problem, but I don't and won't tape em...


I usually skip the first few threads then Teflon...could rope and dope


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## pilot light (Apr 21, 2012)

never tape them masters metallic pipe dope the nasty stuff!


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## Tommy plumber (Feb 19, 2010)

Dangle72 said:


> Hi All,
> 
> I have a boiler system that I just started servicing. The problem that I have ran into is as follows:
> When I test the LWCO, it is an electronic version, the boilers and all the circulators shut down. The system has a leak in the in-floor somewhere in the 12,000 square foot house. The owner doesn't want me to spend the time at this point finding the leak so we just keep adding water to the system.
> ...


 






What ever happened to those pictures?


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## billy_awesome (Dec 19, 2011)

Could you describe more on how everything is wired? maybe a picture of the wiring and how it goes to and from the boiler


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## rjbphd (Feb 5, 2010)

I always install the lwco above the pumps on supply side of boiler, so that way the WHOLE system is protected. 
In this case, before I answer, would need to see this pixs of installation as its sounds fishy to me.


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## pilot light (Apr 21, 2012)

Dangle72 said:


> Hi All,
> 
> I have a boiler system that I just started servicing. The problem that I have ran into is as follows:
> When I test the LWCO, it is an electronic version, the boilers and all the circulators shut down. The system has a leak in the in-floor somewhere in the 12,000 square foot house. The owner doesn't want me to spend the time at this point finding the leak so we just keep adding water to the system.
> ...


 If it didnt shut off the boiler it is wired wrong! the circulator well ?


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## Dangle72 (Dec 17, 2011)

*Pictures of system(Finally)*

Here are the pictures that I said I would send a long time ago.


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## Dangle72 (Dec 17, 2011)

The lwco is wired correctly. When I test it on the test button it shuts everything down.


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## Dangle72 (Dec 17, 2011)

Hi Billy, I will get some pictures of the wiring but it is all controlled by a main controller. One that I have never worked on before. I havn't spent much time looking into as the system is operating, so the homeowner doesn't want to pay to have me sit there and figure everything out.
The homeowner said he had a wiring diagram of the system but I still have not seen it or the manual for the controller. 
I have no idea where the guy got the controller, not Tekmar, Honeywell, Johnson or any of the other common controllers out there for multi boiler systems.


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## Dangle72 (Dec 17, 2011)

Pictures are up now Tommy Plumber.


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## OldSchool (Jan 30, 2010)

I see the LWCO. The pipe is to long and is to small it can't drain

Sent from my miniature laptop


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## pilot light (Apr 21, 2012)

Dangle72 said:


> The lwco is wired correctly. When I test it on the test button it shuts everything down.


 Drain all the water out of the boilers and then do a trial for ignition.I have seen where it wont trip on test but wont start when drained! Mc donnell miller bulldog lwco.


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## pilot light (Apr 21, 2012)

pilot light said:


> Drain all the water out of the boilers and then do a trial for ignition.I have seen where it wont trip on test but wont start when drained! Mc donnell miller bulldog lwco.


 Its a watts replace


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## OldSchool (Jan 30, 2010)

pilot light said:


> Its a watts replace


It's the blue box one pic #1 in the upper right hand corner

Sent from my miniature laptop


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## pilot light (Apr 21, 2012)

OldSchool said:


> It's the blue box one pic #1 in the upper right hand corner
> 
> Sent from my miniature laptop


 It like a green watts sometimes blue saw it!


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## pilot light (Apr 21, 2012)

pilot light said:


> Its like a green watts sometimes blue saw it!


Cant see the connection piping ! Or wiring!


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## OldSchool (Jan 30, 2010)

pilot light said:


> Cant see the connection piping ! Or wiring!


Pic #3 you can see it sticking out from the wall

Also it looks like the LWCO is a dead end.... Piss poor place to put the LWCO

Should be on main loop.... And the tee and pipe should be large enough so it can drain back

Sent from my miniature laptop


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## pilot light (Apr 21, 2012)

OldSchool said:


> Pic #3 you can see it sticking out from the wall
> 
> Also it looks like the LWCO is a dead end.... Piss poor place to put the LWCO
> 
> ...


 A wiring shot too please!:no::whistling2:


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