LWCO

kevin coppinger_4 · September 2004

a lwco on a hot water boiler, most have no LED or light to signal that a low water event happened....do you have something to add aftermarket that would indicate this? Its kind of a pain not knowng what the problem is w/o pulling out a voltmeter.....kpc

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Rookie_3 · September 2004

LWCO

Do you mean something that tells you when the pressure reducing valve has had to make up for lost water in a hot water boiler? Hot water boiler would be better fit with a probe type LWCO. Maybe you want an alarm for low water on a steam boiler? You can use the bottom two screws for a buzzer or a light. When the plunger drops on low water the switch will close for the buzzer or light to signal.
That is if you don't already have a automatic water feed wired there. Maybe more details would help, are you looking for an event that happened with your multimeter? Do Not
change the wires on the LWCO if you are not sure what you are doing, you could by-pass the entire switch which could be tragic.

Rookie_3 · September 2004

Rookie_3 · September 2004

Wayco Wayne_2 · September 2004

Most LWCO's

have an alarm contact. The one I mostly use has an LED to help you visually see the problem. Its a Guard Dog RB-24, by McDonald Miller. WW

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J.C.A._3 · September 2004

I agree with W.W.

But the M&M unit I use is 851-120/851-12 (?)

Both units have 2 leds on top. On commercial units we use the same unit with a different #(which I can't remember) that has a manual reset button. The big drawback is that it doesn't fit in anything under a 1 1/2 inch fitting, due to the depth of the probe. Chris

kevin coppinger_9 · September 2004

Wayne the only model...

I have acess to is the Hydrolevel 170...it has no lights...does have the alarm contacts...what type of small light (LED) could be put on to it? I don't just want to string it to a 25 watt bulb...I had a case where the boiler(HOT Water.., not Steam) went on off on low water...took another tech a while to figure out what went wrong...it would be nice to see right away.... kpc

Ed_13 · September 2004

Your LWCO question

Kevin,

I am a bit confused about your question. On a FHW system, the entire system is filled and pressurized with water. The feed valve is ether turned on or turned off. This creates two conditions to deal with.

The Automatic Water Feed Valve, is basically a Pressure Reducing Valve (PRV) will as keep the entire system pressurized to the preset pressure. If there is no leak, the entire system stays fill and the LWCO is not an issue.

If a system develops a water leak and it has a PRV that is turned on and operational, the PRV should add water to the system to replenish any and all of the water lost in the leak, and keep the entire system full of water. When you go to that call, there will be water leaking. No alarm on LWCO needed here.

If you have the shut off valve prior to the PRV turned off, (such as is required if you use a B&G PRV, or if the PRV is not functional, (corroded shut) , then the system will loose water from the leak, and the LWCO should shut the system off. As the water goes below the level of the LWCO, normally building heat will be affected or stopped altogether. When you get to that system on a service call, it will be in a low water condition and have little or no pressure with probably no heat in some or all zones. You should not need an alarm to find that.

I am not trying to be a smart A**. My question is why you would need an LED or alarm to find a problem with a FHW system that has had a low water the condition.

By the very nature of the FHW system, you will find it ether leaking water and the LWCO did not need to intercede, or low on water, and shut off by the LWCO.

Third option is out of water and the LWCO did not shut it off, in which case bring your ham burgs and hotdogs to roast. That condition is EASY to spot without an alarm in the LWCO.

BTW, that last condition (a dry fire) IS the very condition that the LWCO is installed on a FHW system to prevent.

Regards,

Ed Carey

Ed_13 · September 2004

Your LWCO question

Kevin,

I am a bit confused about your question. On a FHW system, the entire system is filled and pressurized with water. The feed valve is ether turned on or turned off. This creates two conditions to deal with.

The Automatic Water Feed Valve, is basically a Pressure Reducing Valve (PRV) will as keep the entire system pressurized to the preset pressure. If there is no leak, the entire system stays fill and the LWCO is not an issue.

If a system develops a water leak and it has a PRV that is turned on and operational, the PRV should add water to the system to replenish any and all of the water lost in the leak, and keep the entire system full of water. When you go to that call, there will be water leaking. No alarm on LWCO needed here.

If you have the shut off valve prior to the PRV turned off, (such as is required if you use a B&G PRV), or if the PRV is not functional, (corroded shut) , then the system will loose water from the leak, and the LWCO should shut the system off. As the water goes below the level of the LWCO, normally building heat will be affected or stopped altogether. When you get to that system on a service call, it will be in a low water condition and have little or no pressure with probably no heat in some or all zones. You should not need an alarm to find that.

I am not trying to be a smart A**. My question is why you would need an LED or alarm to find a problem with a FHW system that has had a low water the condition.

By the very nature of the FHW system, you will find it ether leaking water and the LWCO did not need to intercede, or low on water, and shut off by the LWCO.

Third option is out of water and the LWCO did not shut it off, in which case bring your ham burgs and hotdogs to roast. That condition is EASY to spot without an alarm in the LWCO.

BTW, that last condition (a dry fire) IS the very condition that the LWCO is installed on a FHW system to prevent.

Regards,

Ed Carey

Ed_13 · September 2004

Your LWCO question

Kevin,

I am a bit confused about your question. On a FHW system, the entire system is filled and pressurized with water. The feed valve is ether turned on or turned off. This creates two conditions to deal with.

The Automatic Water Feed Valve, is basically a Pressure Reducing Valve (PRV) will as keep the entire system pressurized to the preset pressure. If there is no leak, the entire system stays fill and the LWCO is not an issue.

If a system develops a water leak and it has a PRV that is turned on and operational, the PRV should add water to the system to replenish any and all of the water lost in the leak, and keep the entire system full of water. When you go to that call, there will be water leaking. No alarm on LWCO needed here.

If you have the shut off valve prior to the PRV turned off, (such as is required if you use a B&G PRV), or if the PRV is not functional, (corroded shut) , then the system will loose water from the leak, and the LWCO should shut the system off. As the water goes below the level of the LWCO, normally building heat will be affected or stopped altogether. When you get to that system on a service call, it will be in a low water condition and have little or no pressure with probably no heat in some or all zones. You should not need an alarm to find that.

I am not trying to be a smart A**. My question is why you would need an LED or alarm to find a problem with a FHW system that has a low water condition.

By the very nature of the FHW system, you will find it ether leaking water and the LWCO did not need to intercede, or low on water, and shut off by the LWCO.

Third option is out of water and the LWCO did not shut it off, in which case bring your ham burgs and hotdogs to roast. That condition is EASY to spot without an alarm in the LWCO.

Of course, that last condition (a dry fire) is the very condition that the LWCO is installed on a FHW system to prevent.

Steam system are a whole different issue.

Regards,

Ed Carey

DaveGateway · September 2004

What is the voltage reading

What is the voltage reading
at these contacts when the device is in LWCO? Is this a low voltage DC port, or is it showing an AC voltage?

LED's are generally low voltage DC devices, however there are other devices like Neon bulbs which could work off AC.

Radio Shack stocks a number of miniature Neon lamps that will operate off standard line voltages. A small current limiting resistor is usually required in series with the lamp. See the following application note for more detail.

http://www.gilway.com/pdf/appl-neonlamps.pdf

tim smith · September 2004

lwco control

I have used the 550 120 volt model for years, has indicator lights and all, great control. IMO better control than the MM control.

Unknown · September 2004

Seems like a simple question to me

Kevin knows the dynamics of how a hot water system works . We also used to use a LWCO without any indicator lights , so I can relate . The fact is those indicator light can save a tech some valuable time , at the minimum it can tell you that there is power up to that point . And anything that makes my job a little simpler , I am all for .

Kevin , we switched to the Taco model which is around 10 bucks more , but has the indicator lights on the outside , and overall is alot smaller than most . By the time you rig up external lights or an alarm to the LWCO , a model with the indicator built in might be the way to go . Do they stock them at your local supply ?

Jack, CVMS · September 2004

LWCO

Kevin,
Any time we install a control that can lock out (manual reset hi-limit, LWCO, etc.) that does not have an indicator light, we install one. Just takes a little LED or neon pilot light (depending on the voltage at the control) available from Radio Shack or most other electronics supply houses. Most that we use just require a 5/16" hole for mounting. Connect them to the NC terminals. So long as the contacts are closed there is no voltage differential between the terminals. As soon as the contacts open, there is a difference in the voltage and the light comes on. Sure simplifies and speeds up diagnoses.
In regards to PRV's and make-up water: In our part of Alaska we don't use it. Virtually all of our systems are filled with a propylene glycol solution to prevent freezing of any part of the system. The last thing we want is to have that solution diluted without the homeowner or us knowing it. If the system loses pressure there's a leak and we fix it, that way no make-up water is needed.

kevin coppinger_4 · September 2004

I'm glad someone....

understands me...The whole reason I ask...I had a situation where I had installed a system and later on (2 months later) the homeowner added a outside wood boiler...they called me in the spring wondering why when they turned off the outdoor boiler they had no hot water...I was an hour away and was trying to diagnose over the phone...hard to do if there is no indicator of the LWCO is cutting of all the power... I guess I will switch to a new control...kpc

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LWCO

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