CycleGard LWCO

Steve_211 · February 2

Aside from protecting the boiler from firing when the water level is low, what other function(s) does the CycleGard do?

nde · February 2

Call me a cynic but 1)wear burner components out at 3x the needed rate 2)mitigate hack install problem of water leaving boiler too fast when firing 3)reduce number of calls to boiler support for said installers/upset homeowners 4)reduce efficiency of the steam cycle by constant short cycling.

If your install is proper replace it with a safgard. Your boiler will thank you.

SteamingatMohawk · February 2

Please explain the 3x.

Assuming you are referring to the Intermittent Level Test function, please provide the technical basis for your assertion on efficiency.

In my boiler it shuts off the flame for 90 seconds every 10 minutes. One thing it does do is let the pressure in the system decrease for that time...low pressure is better than high pressure according to the experts on HH and elsewhere.

Naysayers have at it.

Jamie Hall · February 2

Usually the Cyclegard will also be set to activate the automatic water feeder, if you have one, in addition to shutting off the burner if the water is too low.

Some installers don't really like Cyclegards, preferring Safeguard, which do those same two primary functions, but don't turn the boiler off every ten minutes -- as you see with @nde 's comment above. However, there are reasons to prefer the Cyclegard in some applications. First, if your system is one pipe steam and has thermostatically regulated vents, as many systems do, the shut down allows the TRV to gain control of the temperature in the space. Otherwise the TRV can't function properly. Second, the water quality in some boilers produces a good deal of foam, either naturally or because of added chemicals or cleaners, which will fool probe type low water cutoffs such as the Cyclegard and Safegard. In order to read the actual water level, the burner must be shut off long enough to stop boiling, otherwise a dangerous low water condition can develop without the LWCO tripping.

Sylvain · February 2

about return lag time, some tips (from a commercial blog):

https://www.deppmann.com/blog/service-tip-of-the-month/steam-boiler-flooding/
https://www.deppmann.com/blog/service-tip-of-the-month/updating-old-steam-systems-with-modern-boiler-feed-unit/
https://www.deppmann.com/blog/monday-morning-minutes/steam-boiler-feed-unit-receiver-sized/

ChrisJ · February 2

Jamie Hall said:
Usually the Cyclegard will also be set to activate the automatic water feeder, if you have one, in addition to shutting off the burner if the water is too low.

Some installers don't really like Cyclegards, preferring Safeguard, which do those same two primary functions, but don't turn the boiler off every ten minutes -- as you see with @nde 's comment above. However, there are reasons to prefer the Cyclegard in some applications. First, if your system is one pipe steam and has thermostatically regulated vents, as many systems do, the shut down allows the TRV to gain control of the temperature in the space. Otherwise the TRV can't function properly. Second, the water quality in some boilers produces a good deal of foam, either naturally or because of added chemicals or cleaners, which will fool probe type low water cutoffs such as the Cyclegard and Safegard. In order to read the actual water level, the burner must be shut off long enough to stop boiling, otherwise a dangerous low water condition can develop without the LWCO tripping.

Any reason they can't add a thermostatic switch directly to the outside of the block to interrupt the 24VAC?
Wouldn't that actually stop dryfiring etc?

Jamie Hall · February 2

Interesting idea, @ChrisJ . I think it would take some work to determine the best place to put it, and to determine what temperature to set it at. But it would be an additional safety, which is never a bad thing. For myself, I really like systems which have two LWCOs of different operating principles -- such as one probe and one float. The float, of course, does take maintenance to work properly...

Sigh.

ChrisJ · February 2

Jamie Hall said:
Interesting idea, @ChrisJ . I think it would take some work to determine the best place to put it, and to determine what temperature to set it at. But it would be an additional safety, which is never a bad thing. For myself, I really like systems which have two LWCOs of different operating principles -- such as one probe and one float. The float, of course, does take maintenance to work properly...

Sigh.

They're dirt cheap and used everywhere including forced air furnaces.
Just a simple bi-metal snap switch, I think they cost a few dollars.

I'm sure the best temperature could be figured out, but honestly I'd think anywhere on the block would be better then dryfiring until the thing melts everything on it and catches things on fire.

I'm honestly confused as to why none of them have one. Perhaps there's a detail I'm missing.

nde · February 2

I've had steam heat for 16 seasons, 3 of them regretably with a cyclegard which shipped default on new boiler (no coicidence see above or below) so I have plenty of observations on how it operates. I swapped it out this fall--up there with best things I've ever done along with gorton 2 mains and insulating pipes.

My typical burn time is 25-30+- minutes depending on weather (no setbacks). The cyclegard 450 checked every 15 minutes for 60 seconds, burner then purges for 30 seconds before refire. So 13.5 minutes per 15 system can fire. Typical run was tstat calls, burner fires, cyclegard cuts in, burner off 90 seconds, refires then cyclegard cuts again before tstat satisifed, burner fires. One of the cycles would always be short, often a minute or so if early or late in the call often 2 short one "normal" at 13.5. Meanwhile the poor gas valve has had to open/close 3x time vs 1x time. That's my 3x. Rarely it would coincide to just 2x.

There is extra wiring for "smart sense" feature which would have limited to 2x but if your that smart you dump the cyclegard....Relative to ineffcient I dont find a product that short cycles the boiler 90 seconds on average 2x per run to be efficient. Steam drops out of rads and risers, air comes back in very quickly so yeah that happening twice every run vs never happending is inefficient in my book.

System runs much better on safgard or a manual lwco as I had for 13 years. Cyclegard is junk unless you have a hack install, then it is "great" for your lazy installer and "not our problem" boiler support rep.

Sylvain · February 2

ChrisJ said:
Any reason they can't add a thermostatic switch directly to the outside of the block to interrupt the 24VAC?
Wouldn't that actually stop dryfiring etc?

About 1$ but, some additional circuitry (relay) might be needed in such a way that the boiler doesn't start again.
Then a reset switch and an overtemp indicator so you know why the system stopped. One might need to push the reset to first start the boiler when heating season starts.

EBEBRATT-Ed · February 2

I think a temp sensor on the block would probably be to slow to respond.

ChrisJ · February 2

EBEBRATT-Ed said:
I think a temp sensor on the block would probably be to slow to respond.

It'll respond a lot faster than the fire department.

ethicalpaul · February 2

By no means are they all 10 minutes Mine I think is 20 minutes. It’s really not a big deal.

bburd · February 2

Cyclegard...aka "psychogard"! 🤣

ChrisJ · February 2

ethicalpaul said:
By no means are they all 10 minutes Mine I think is 20 minutes. It’s really not a big deal.

Jamie Hall · February 2

Folks, I agree that on most systems the Cyclegard cycle feature is a nuisance. However, as I noted earlier, there are two situations where it is not: if your boiler water for some reason foams (chemicals or water quality) or where you have TRVents on a one pipe system, and the system must cycle off for the TRVents to exert control. There is a place for everything...

SteamingatMohawk · February 2

@nde Steam drops out of rads and risers, air comes back in very quickly so yeah that happening twice every run vs never happending is inefficient in my book.

I find this comment interesting. What happens that steam drops out in 90 seconds of no flame? The metal in the boiler is still hotter than the water transferring heat to the water.

I like the Cyclegard, but am willing to listen to others. The perspective of others needs on fact/measurement/observation/etc.

My boiler does not have the capability of starting the 10 minute count at the outset, so there al most always a less than 10 minute first Burn.

@Jamie Hall What is the nuisance?

MikeGordon · February 2

Hello Steve_211;

The advantage of the Hydrolevel Cyclegard versus a conventional probe type steam boiler low water cutoff (LWCO) is protection against boiler damage caused by foaming of the boiler water. In practical use, all steam boiler water foams, to some degree, when steaming. As total dissolved solids and oil/organic contaminate concentrations increase, the amount of foaming increases, as well as the duration the foam persists after steaming stops.

Probe low water cutoffs work by monitoring the electrical conductivity from the LWCO probe to ground. In the range of conductivity/resistance monitored by the LWCO control, water will conduct electricity and air will not. If the control senses no water, the burner operation is interrupted to protect the boiler from a dry fire condition. However, in certain rare instances, boiler water foam will also have just the right conductivity to mimic water.

This then would allow the boiler to continue to fire when there is foam in the boiler up to the level of the probe, but a water level below the minimum water line. This can result in a dry fire condition, and boiler heat exchanger overheating with cast iron section leaks and cracks.

When the Hydrolevel Cyclegard was first introduced by Burnham in the late 1990's, it did a magnificent job and greatly reduced a very real problem. It's an excellent safety feature in my opinion.

Hope this helps.

Mike Gordon

Jamie Hall · February 3

The nuisance, @SteamingatMohawk , is mostly psychological. People seem to freak out when their boiler takes a break for a minute or two -- whether it is a Cyclegard or a vapourstat doing the dirty deed. I don't have a problem with it.

And I agree with @MikeGordon on the safety benefit.

Steve_211 · February 3

Well that explains why, when I hit the times set on my programmable thermostat, my cold boiler first fires for 15-20 minutes and shuts off without producing any steam.

ethicalpaul · February 3

Yes, for 60 or 90 seconds. Did you survive?

Your house had apparently gone for many hours without heat if it fired for 20 minutes without steaming. One more minute won’t hurt 🙂

Jamie Hall · February 3

Steve_211 said:
Well that explains why, when I hit the times set on my programmable thermostat, my cold boiler first fires for 15-20 minutes and shuts off without producing any steam.

seconds, not minutes, I hope? If your boiler fires for 15 to 20 minutes without steaming... problem

SteamingatMohawk · February 3

Perhaps, what he is referring to is sensing heat at the radiators, versus heat in the mains.

My system (~100 year old house) takes a while from cold iron to steam at the radiator vents around that long. A full cycle is 45 minutes to an hour. These mild winter days suppress the need for heat and the system frequently cools down pretty far before the next demand.

@Steve_211 might want to check how long it takes for the boiler to actually start sending steam to the mains and to the radiators to make sure the system is delivering the heat properly.

It could also be affected by insulation on the supply mains and risers.

neilc · February 3

has main venting been discussed ?

ethicalpaul · February 3

OK folks, for a public service, during a 3 degree recovery today I went and had a look at my evil CycleGard so I could explain what it does on my system.

Mine is a 1560 model so every 15 minutes it shuts down for 60 seconds.

I started my observation toward the end of this 15 minutes so I could watch my system pressure during the shutdown.

Leading up to the shutdown, I was bouncing around 1" of water column (.0357 psi). My main was obviously full of steam, and my radiators were pretty full of steam, probably some were full and some might not have been.

At the shutdown, pressure dropped into vacuum within about 15 seconds. I didn't have a +/- gauge on at the time so I don't know how far it went.

My main vents are nearby so I monitored those during this time. They never opened and no air intake occurred there.

Air was definitely being pulled into one or more radiator vents (see below), but the overall system pressure was still negative when the CycleGard released its evil grip on my burners and let them fire again.

At 15 seconds, the needle crossed back into positive pressure as steam was being produced again (there is no measurable delay in making steam after only 60 seconds of burners off).

At 30 seconds I was back at 1" of pressure. The needle steadily rose over the next minute or so until it got to 4" of pressure (.143 psi). This is because the steam was having to push the inhaled air back out whichever radiator vents let it back in.

But keep in mind all the radiators are still plenty hot and radiating. No resident of this house could ever tell that the boiler was off during at time unless they were sitting next to an inhaling vent during the vacuum phase (and paying attention), or sitting in the basement.

Over the next couple minutes, the pressure dropped back to 1" because the air was making way for the steam, allowing the steam to condense on more area of radiator interior.

The earth kept spinning, my boiler wasn't harmed, and I felt secure that I had enough water in my boiler since its height was measured minus boiling and splashing.

I still say this is the safest most reliable LWCO ever created and it's no wonder several manufacturers ship it with their boilers.

Jamie Hall · February 3

Nice set of observations, @ethicalpaul . Kind of makes me point that the angst around the Cyclegard is mostly psychological...

Which, at some risk of making me a target (as usual) also extends to the similarly brief shutdowns from a vapourstat when the boiler is slightly oversized for the particular day...

STEAM DOCTOR · February 4

MikeGordon said:

Hello Steve_211; The advantage of the Hydrolevel Cyclegard versus a conventional probe type steam boiler low water cutoff (LWCO) is protection against boiler damage caused by foaming of the boiler water. In practical use, all steam boiler water foams, to some degree, when steaming. As total dissolved solids and oil/organic contaminate concentrations increase, the amount of foaming increases, as well as the duration the foam persists after steaming stops. Probe low water cutoffs work by monitoring the electrical conductivity from the LWCO probe to ground. In the range of conductivity/resistance monitored by the LWCO control, water will conduct electricity and air will not. If the control senses no water, the burner operation is interrupted to protect the boiler from a dry fire condition. However, in certain rare instances, boiler water foam will also have just the right conductivity to mimic water. This then would allow the boiler to continue to fire when there is foam in the boiler up to the level of the probe, but a water level below the minimum water line. This can result in a dry fire condition, and boiler heat exchanger overheating with cast iron section leaks and cracks. When the Hydrolevel Cyclegard was first introduced by Burnham in the late 1990's, it did a magnificent job and greatly reduced a very real problem. It's an excellent safety feature in my opinion. Hope this helps. Mike Gordon

If boiler water foams, to the extent that the cyclegard, is beneficial, than you have serious water quality issues that are not addressed by the cyclegard. Sort of like putting a device in your car, that shuts the car every 20 minutes, to compensate for those who only change their oil every 10 years. Ok ok. Not perfect comparison. But you get the idea. And heaven forbid, you have a smart thermostat, after the cyclegard in the circuit. Lots of smart thermostats take significant amount of time to reboot. So every 20 minutes, CG shuts boiler for 60-90 seconds. Then smart thermostat takes 1-10 minutes to reboot (but CG has already started it's next countdown). Run cycles are even shorter.

ethicalpaul · February 4

But Steam Doctor, can't it be difficult to know how much your water is bubbling/frothing/foaming unless it's very severe?

On my previous boiler which wasn't surging after I worked on the water (I had installed my first sight glass on it and could see it wasn't surging anymore), and the gauge glass wasn't moving very much, and yet I lowered the water level while it was steaming to a little below the bottom of the sight glass, but the probe LWCO still thought the water level was OK until I stopped the boiler.

After I stopped it, then it registered low water level. The CycleGard seems useful in these cases. Anyway, I've said enough in this thread, but I look forward to the next thread!

STEAM DOCTOR · February 4

Me too. I will probably always respect you. And I will probably never agree with you about this point (unless of course,you come around to my side of the ring).

ChrisJ · February 4

We all need a meet in person and a good game of cards or dominoes to discuss all of this over.

Or several.

And if that doesn't work after some time we can just switch to Monopoly and end the friendships for good.

.

SteamingatMohawk · February 4

@ethicalpaul Nice experiment, except, as you stated, you could not determine how much vacuum was created. If you really want to know, swap your gauge for one that does both vacuum and pressure or install a manometer so you can see the change in pressure directly.

Caution and I am not trying to insult you by making such a statement, do not leave the manometer installed. Some folks reading this may not be as technically competent.

Additionally, I wonder how much of the pressure change has to do with recovering from a 3 degree setback. How long had the system been off before you started your experiment? It makes a difference in how cold the iron was compared to a regular periodic call for heat during the day.

SteamingatMohawk · February 4

I use this for my gas pressure adjustments. It's interesting because of how the device is built with a tube within a tube. It takes a little getting used to.

https://www.testequipmentdepot.com/yellow-jacket-78075-water-type-scale-manometer-2-0-15.html?ref=gbase&gad_source=1&gclid=CjwKCAiAiP2tBhBXEiwACslfnnUVF_qV0NBJLHDwmdLqylXnIIXVblf1Q47CWewdBtfpTp_9HaL7ABoC0cQQAvD_BwE

ethicalpaul · February 4

SteamingatMohawk said:
@ethicalpaul Nice experiment, except, as you stated, you could not determine how much vacuum was created. If you really want to know, swap your gauge for one that does both vacuum and pressure or install a manometer so you can see the change in pressure directly.

Caution and I am not trying to insult you by making such a statement, do not leave the manometer installed. Some folks reading this may not be as technically competent.

Additionally, I wonder how much of the pressure change has to do with recovering from a 3 degree setback. How long had the system been off before you started your experiment? It makes a difference in how cold the iron was compared to a regular periodic call for heat during the day.

I know how to measure vacuum, thanks

, but I wasn't interested in how much vacuum really for this observation.

When I started observing, the whole system was warm/hot. I had just raised my thermostat 3 degrees to make sure it would keep calling for heat while I observed it.

CycleGard LWCO

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