helpwith ct boiler and gaurd dog

JimH.

I am installing a CT 45 Crown oil boiler and a "Guard Dog" LWCO. I cant seem to figure out the appropriate wiring to the aquastat. Do I need a seperate transformer to power this gadget, can anyone help, Thanks, Jim

Alan(CaliforniaRadiant)Forbes

I believe

that it's only a switch, just like a spill switch or a flame roll-out switch and all you have to do is wire it in parallel with the end switch to your boiler. So, before your boiler can get a signal to turn on, the low water cut-off (GuardDog) has to be in the closed position.

You don't need a separate transformer.

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Brian (Tankless) Wood

I believe that ought to be

series, Alan. If it's in parallel, it won't interrupt the circuit.

Brian in seriously humid Swampland, where the talk is about AC. The only heat problems we have here, are of the solar-gain type.

Take care, y'all.

J.C.A.

Alans right.(except the \"parralell\" part)

It should be series wired. The wiring diagram is marginal, but the text makes more sense. Wire it in the "gas safety 24V line" and it just becomes another switch.

We're starting to get a pile of calls from insured businesses requesting these, and a "manual re-set high limit". Luckily, they can be wired in the same limit string, and I'm finding it's easy to put them before all the factory supplied "failsafes" . Good luck, and don't be intimidated. It's easy! Chris

Alan(CaliforniaRadiant)Forbes

Swampy

Thanks for the correction........series is right.

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Unknown

Sounds like you have the 24 volt LWCO ?

Which model Guard Dog is it ? If its the RB-24 , your are going to need a transformer to power the cutoff . Red and white are the power wires and go directly to the transformer , and the 2 yellow wires are the end switch . You can simply run the 2 yellow wires to T and T on a cad cell relay , but the best way to do it is to run the 2 yellows to T and T of a single relay , which would cut out all the power in a low water situation - to the burner and all the circs if used .

If its the RB 120 , you would want to power the LWCO first and run power to where it needs it after the LWCO . If memory serves me , hot from the switch goes to terminal 1 , neutral to 2 , jumper in between 1 and 3 , and power your aquastat from 4 . Good luck .

J.C.A.

OOPS !

Missed the oil part., but I'm still standing on the series wiring !Burner doesn't care if it's 120 or 12 . Just make it interrupt the FIRE !

hot_rod

I've found

the 120 volt models to be the easiest, most versatile one to install. I connect them first in line after the disconnect. This will protect everything downstream, boiler, pumps, etc.

With either the 24 volt or 120 volt, they both need power to operate. Then use the switched lead to the "load"

hot rod

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JimH.

thanks, Ron. I was trying to figure out a way to power it off of the existing Honeywell aquastat, but got frustrated. It must be the LB 24, as it is definately lo voltage. Would the high voltage one be a better choice next time for oil?

JimH.

WOW thanks guys for the input. I forget the numbers of the aquastat, its the cheepie 8184? This job has the boiler on the first floor, so I thought it a good idea, but the wiring diagrams are all for gas controls and I am having a time, as the proper diagram for the aquastat was not included for me to figure out where I could tap in for cutoff and power. The Crown manual was of little help, as it just shows power in and out of the control.

Unknown

Yep , the high voltage

is a better choice when using it on an oil boiler . If it was gas , the boiler most likely is wired for low voltage , and has a transformer installed - makes it easier witha 24 volt LWCO .

We wire the LWCO so it cuts power to everything . Someone here , I forget who , said that a runaway boiler , without a LWCO , exploded when the circ kicked on and dumped water into the dry fired bomb . Better to be safe .

JimH.

I am leaning toward hooking it in series with the thermostat, so the circ or burner wont come on. I never thought about the circ feeding the dry fired bomb. I always thought it would be feed water. I loathe the idea of hooking another transformer up though, that will make three total. Sure would like to figure out how to steal a little power from the aquastat/circ control.

sootmonkey

5.5 amps

you my want to check the amp rating of your lwco. the ones we use are rated @ 5.5 amps. you can only put 5.5 amps through them.

Unknown

You should only need one transformer

for the LWCO itself . Since the end switch is low voltage , you can run those 2 yellow wires to a single relay - we use the Taco or the Argo . Then you can power the aquastat from the relay and the LWCO can cut power to everything . But if you don't want to go this route , the next best thing is to run the 2 yellow wires from the LWCO to T and T of the burner .

If its just one zone , running it in series through the thermostat leg does cut out everything - but that is only if its a cold start boiler .

JimH.

Yes it is a cold start boiler, Ron. L814a1124 with a LB24. Beckett burner. I wonder if the output from the LWCO is an actual switch or a solid state type thing that may be sensitive to phasing with the oil primary control.

JimH.

Yes it is a cold start boiler, Ron. L814a1124 with a LB24. Beckett burner. I wonder if the output from the LWCO is an actual switch or a solid state type thing that may be sensitive to phasing with the oil primary control. Just went up and fired it for the first time. Had a hard time getting a good combustion test as it heats up pretty fast.I just left the LWCO unhooked for now, its 90 degrees around here so I left the unit off.