Taco low water cutoff ratings

Unknown

for the clarification Bob .

Unknown

I was told today

to break the oil burner alone using the Taco 120 volt LWCO , model number LNA1203S-1 . On a typical 2 or 3 zone install , I power everything after the LWCO .

Seems that we've been having a more than normal failure rate , and they believe the amp draw is the problem . I know a Riello draws 2.2 amps , the circs maybe 3/4 amps each . The spec sheet says the rating is 7.5 amps full load , 43.2 amps locked rotor ( what does locked rotor mean ? ) .

Does anyone else power the burner and circulators after the LWCO like I do , and do you have any problems with the control a few weeks or months after the install ? I'm never the one to go back and see what happened , so I'm not sure how the problem was diagnosed . Thanks in advance .

bob_50

Locked rotor amps

is the amount of current draw on starting when the rotor is stationary. It's usually approximatley 5 times full load amps.

Unknown

Locked rotor is the motor

at rest. The power to get the rotor moving is the starting amperage which is typically a 6 to 1 ratio. Six times more amps to start than to run.

Firedragon_4

Question: How does someone

expect you to do this and comply with code, NFPA31 and NFPA70?

If they want an isolation relay in there I think this is going to get expensive and I'd consider another way, JMO!

I've heard of several of these problems lately and I'm just wondering what's really going on. BTW, there is more than one lwco company involved.

Another note of interest, due to the recent changes in components all of the oilburners out there with PSC motors, interrupted ignition and solid-state ignition controls don't draw more than 2.5 amps anymore!

clammy

hey ron

I always wire my lwco as you have stated and never had a promblem but i always use a mcdonald miller rb122 model and i've used them with up to 7 circs with a beckett burner and no promblem you could always add a isolation relay ,but that being said i'm a taco fan but not there lwco had one fail 2 years ago and the bolier dry fired and continued to fire till the HO shut it off noticing a foul odar .Don't like safegaurg eithe r always stick to the good stuff mc donald miller peace clammy

Unknown

LWCOs on hot water boilers

although have been a code since the mid 90s I believe , has only recently been an item we include on every boiler on Long Island . With the failure rate we've been seeing , if every one of the hundreds of thousands of boilers in the area had one on I can guarantee the number one call back over the winter would be LWCO related . Makes you wonder if the added benefit will outweigh the downside of not having one ?

Unknown

Tomorrow

I'm going to see if we have any of the " failed " controls in the shop , and take one to my job . I'll temporarily throw it on the boiler and see what happens . I'll also ask how many have failed so far . From the way my supervisor worded his request ( demand ) , I think it's alot . I just can't see it being an overamp draw if it's the boiler and maybe 3 circs and a multizone relay on the contacts . Next 3 zoner , I''l take an amp reading with everything running . Thanks Clammy .

Firedragon_4

Follow-up!

ron jr, a lot of this is in the wiring and you should be able to carry any of today's oilburners and a couple of small pumps. But, the pumps shouldn't be on the burner circuit in hindsight. lchmb picked me up on my site about this.

I'm seeing some similar problems with some gas equipment, but it was piped primary-secondary with two large pumps and that made sense. Again, in all cases the lwco should just be breaking the burner circuit.

It may also be due to RF problems. The new electronic stuff is very critical to polarity and grounding.

Unknown

The instructions

show only the burner circuit being broken through the LWCO . I began to power everything after the control when we started seeing oil burners with a constant hot leg . I guess I can just interrupt the burner and the constant hot with a bit more wiring , maybe . Thanks George .

Maine Ken

I use OEM 170's and run ALL power through it. Never had a problem. I don't want my pumps running w/ no water.

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Unknown

Ron

Stealing the 120 volts for your other zoning devices off of the 120 volt leg to the burner control is not advisable. Those wires are part of the tested and certified wiring harness that is provided to keep the control energized for logic in the running and off cycle and should not be tampered with for liability and safety reasons. That's not to ay that it will not work...it just is not advisable. Power for those external zoning devices should come from a junction box external to the internal boiler wiring harness.

As George stated, you should only be breaking the voltage to the burner with the LWCO anyway. This would only involve breaking the L1 to the Aquastat relay in the service switch box. Same goes for the Firomatic Thermal Safety Switches that some localities require. I'm not sure what the symptom is that you are encountering, but it is of utmost importance that you keep the end of the probe away from the back wall of the tee you are mounting it in. Also teflon tape on the threads is not advisable. As George also stated, proper polarity and proper grounding is important with today's elctronic controls. I would advise contacting someone at Taco about this. I believe the number is (401)942-8000 and ask for Joe Mattiello or George Tabor. Hope this helps.



Glenn Stanton

Manager of Training

Burnham Hydronics

U.S. Boiler Co., Inc.

Unknown

For what it's worth

We're getting a lot of calls that turn out to be problems with water boiler 110 volt LWCO's, and the thing they seem to have in common are the brand name Taco.

I'm a HUGE fan of Taco products, so I hope this is taken as advice; that we're seeing much the same thing.

I'm not usually privy to the solution, as success rarely gets reported back to us, in tech service....especially when it doesn't involve a product that we offer. I don't know what the correction has been.

Noel

Unknown

Glenn

We do not steal power from the oil burner . We power the LWCO directly after the service switch . Power the H , neutral to N , we throw out the chincy jumper that comes with the control and use our own wire between H and COM . The NC contact then powers everything . The hot leg to the burner is always powered as long as the LWCO is working properly and the power is on . We don't touch the tested and certified wiring harness . We use a 1 1/2 inch by 3/4 by 1 1/4 black tee right off the top of the boiler for the control . Just a light smear of Rectorseal on the threads of the cutoff - never on the first few threads .

If the control contacts are rated for 7.5 amps and all my equipment is drawing less than 4 amps , why wouldn't it be feasible and more safe to run everything through the LWCO ? What am I missing ?

Unknown

I'm in the same situation

I hear about the problems , not the causes . It could just be the water purity dial being set wrong , too much thread sealant , too much Teflon on the nipples , etc... I'd like to know the real cause before I change the way I wire my boilers . Noel , are you going to be at the Melville Mariott Expo Sep. 27 ?

Unknown

Ken

would you happen to know the contact rating for that brand cutoff ? Thanks .

Unknown

I'll be there.

I'll look for you.

Noel

sootmonkey

Maine Ken

Maine Ken, yep, we use the same, and wire them like ron jr does. thousands out there, only a few problems with the probes leaking. and i mean few. i think if you look, oem is only rated for 5.5 amps. oh well, i have never seen one burnt up from high amps....but....it says 5.5 amps.

Maine Ken

5.8fla, 34.8lra

consumption = 7va

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Unknown

Ron

Maybe I'm misunderstanding your post but I took it to say that you are powering the other zoning devices off of the always hot burner wire. I checked the Amp rating of the OEM-170 that Ken is using on Hydrolevel's website and it has 5.8 amp ratings. As I stated before though, the common things we see in the field involve probes that are too close to the back wall of the tee (need to be 1/4" or more) and teflon tape and excessive pipe compound. Sounds like you are up to par with all of that. I would give Joe or George a call though.

Glenn

Glenn Stanton

Manager of Training

Burnham Hydronics

U.S. Boiler Co., Inc.

Dave Palmer_3

Ron

thats the way we wire it,all thru lwco first. About 1 out of 12 jobs have control call backs. Water purity adjust doesnt change the problem. May go back to guard dogs,Dave

Unknown

I'm doing that too

The always hot wire to the burner is pigtailed in with the hot to the aquastat and any relays - powered by the NC contact of the cutoff . I connect all the wiring in the juction box I install . I don't rewire anything from the factory . Are you saying the always hot to the burner should go right to the burner from the service switch ?

Unknown

Ron

For some reason I had pictured you branching into the black wire after the junction box and not in it. A "Senior Moment" once again.

Glenn Stanton

Manager of Training

Burnham Hydronics

U.S. Boiler Co., Inc.

Unknown

No problem Glenn

Thanks for the advice .