Replace cycleguard with with manual or automatic reset safgard?

rgargoum

Hi all,

I am returning for more information regarding my one-pipe system.

A cycleguard is part of my system, and I have been made aware of its shortcomings. My system also has a mechanical LWCO and a VTX automatic feeder (which tends to overfill my boiler, so I have the valve to it shut off).

I'd like to decide on a new LWCO, but I'm not sure I understand the difference between an auto or manual reset, when describing the models available by safgard. I lose a little bit of water to leaks every week, but have been putting in a little more water to compensate whenever I drain and exercise my manual LWCO.

Thanks again for all your help!!

Jamie Hall

The difference between manual reset and automatic is simple -- the automatic reset will allow the boiler to restart when the water level rises. The manual reset, as the name implies, requires the operator to push a button to reset it and allow the boiler to restart.

In my humble opinion, one should have both. The automatic reset LWCO (of whatever type) set higher and, preferably, controlling an automatic water feeder (which should have a meter on it, by the way). This one allows the boiler to keep operating even if the operator doesn't check it. The manual one should be set lower, but still at a safe level. It will turn the boiler off and keep it off until someone becomes curious and, hopefully, finds out why the boiler lost water, fixes the problem, and then -- and only then -- resets it.

Your VTX feeder should not overfill the boiler. Either it is not adjusted or set correctly or possibly leaking, or the mechanical LWCO is sticking or not set properly. Fix it.

SteamingatMohawk

what are the shortcomings of the cyclegard? I have one with the intermittent level test which has worked fine for 20+ years.

Hap_Hazzard

It only lets the boiler run for ten minutes at a time, so it never gets to cycle on pressure.

SteamingatMohawk

That's not a bad thing if you believe in the thumb rule of keeping the pressure as low as possible and following the 1898ish 2 psig Carbon Club standard that Dan talks about in his books.

Actually the Pressuretrol or whatever you have is probably the only pressure control safety function other than the relief valve.

I've read that code for commercial boilers is for two limit controls, where the second is set slightly higher and is a backup for the lower set one.

I have the 10 minute for 90 second setting on mine and prefer that test to keep the pressure lower over the Pressuretrol. The only times my Pressuretrol gets involved is on the days where the boiler doesn't run often and the system gets to cool down further between demands, thus running longer to get the building satisfied.

I have read comments on both side of the discussion about this.

rgargoum

Gosh!

From what I've read about the cycleguard, it seems that it limits the efficiency of my system by letting things cool down just as steam starts to build.

I didn't suspect that removing it would cause excessive pressure to build, but I guess I can see this happening. This leaves me even more puzzled about what to do with my system.

I have long been suspicious about certain components of my system, specifically of my pressurtrol and my cheap pressure gauge. I'm not sure which one is at fault, but sometimes the pressure gauge reads up to 8 PSI and the system is still running. I know that the pressurtrol shouldn't let this happen. I also have read that pressurtrols are unreliable when set at low settings. For this reason I've considered installing a used mercury vaporstat, but not sure if I'm doing the right thing or not.

The problem of excess pressure has not been a problem lately though, as per the suggestion of someone on this forum (see my other thread), I shut off the supply from my VTX auto-feed earlier in the year due to over-filling and flooding of the boiler about once per week. The VTX was set to fill per the cycleguard electric LWCO. After I shut of the auto supply, I have been able to watch the water level on a daily basis and add a little water as necessary (about a gallon every 2 weeks) to account for system losses and to exercise my float-type LWCO.

Still, I don't know what the best approach will be.

I would like to get the efficiency of my system up, but of course not compromise safety.

I really need an expert's help. There are many components to this system, and I don't know how all of them work together.

SteamingatMohawk

Do yourself a favor and itemize the issues you have in one place in this discussion, so all of us are on the same page. Many of the guys using Heating Help are orders of magnitude more knowledgeable than I am. They are tremendously useful. It will be to your benefit.

SteamingatMohawk

You said your cyclegard is a float-type, I don't think that is true. Look up your model on the hydrolevel.com web site.

Hap_Hazzard

rgargoum said:

Gosh!

From what I've read about the cycleguard, it seems that it limits the efficiency of my system by letting things cool down just as steam starts to build.

I didn't suspect that removing it would cause excessive pressure to build, but I guess I can see this happening. This leaves me even more puzzled about what to do with my system.

The pressure will only build to the extent that the boiler is oversized, and only when it has to run for an extended period to satisfy the thermostat. Even then, the pressure shouldn't be excessive if the pressure-limiting device cuts out at a reasonable pressure. A Pressuretrol can be set to cut out at 1.5 lb., which isn't really excessive, and there are Vaporstat models that can cut out at a few ounces of pressure. But setting a low pressure limit will cause short-cycling if the boiler is oversized, so getting the boiler size right is probably the most important consideration when it comes to efficiency.

rgargoum

Thanks for your responses!

Here is a pic of my system.

It includes:

1. Peerless boiler
2. Riello 40 natural gas burner
3. cycleguard cg450-1560 lwco
4. VTX-120 water feeder
5. Mcdonnell & Miller mechanical lwco
6. Honeywell pressurtrol

The VTX-120 is set to "2 min" and "LWCO". I was having trouble during the winter with the boiler flooding intermittently. Not sure exactly why. Per the recommendations of someone on this board, I cut off the supply to the automatic feeder and everything worked fine, and I had to add only a little water every 2 weeks or so. However, I would like to find the correct long-term solution for this.

My plan, for now, is to replace cycleguard with Safgard 170 or another recommended LWCO. I am still unsure how the LWCO interfaces with the auto-feeder, or how the two LWCO's interact with one another. Also, I am unsure about the lockout feature of the auto-feeder (I think it locks out the burner if it fills for 2 cycles and there is still a low-water condition).

Any help is hugely appreciated.

SteamingatMohawk

If you don't have any information on the LWCOs and auto feeder go to the manufacturer web sites and get the literature. It really is useful.

The pigtail for the Pressuretrol just begs to get clogged. Make sure you clean it periodically, like before the beginning of the heating season. As an option, if you are so inclined is to change the pigtail to a vertical one, using an elbow to go from horizontal, to vertical, then use a straight pigtail (pictures of a straight pigtail are available on Google).

Additionally, your system seems fairly new, so the Pressuretrol probably does not have a mercury switch. If it does have a mercury switch, the orientation of the Pressuretrol to the coil of the pigtail can affect the operation of the Pressuretrol. Again, there are numerous examples on the internet.

Jamie Hall

First thing you need to find out is what is controlling the autofeeder. It will -- or should -- activate at a higher level than either of the low water cutouts. It may be from the mechanical McDopnnell Miller. They have two separate switches which activate at different levels; a common arrangement is to have it signal the autofeeder from the high level switch, while the low level switch is a low water cutout.

Your VXT has, as you have found, separate controls for the time delay on feeding and for the amount to feed. I do not like the LWCO setting for amount. Particularly if you have slower returns, it can overfeed quite dramatically. Rather, I would prefer to see how much water it takes to go from the trigger level after the time delay to the normal water line, and set the feed amount to that. This may take some experimenting.

Your VXT also has, as you have found, a lockout if it tries two successive feed cycles and the burner doesn't come on after two successive feed cycles. This is not a low water cutout protection! There are a variety of evils which this is designed to protect against -- but low boiler water isn't one of them.

Rather, the two low water cutouts should be wired in series with the pressure control, and tripping any one of them should stop the burner immediately. Some boilers are wired with them in a 24 volt control circuit. Some are wired with them in a 120 volt circuit, so watch out for voltage. In my view, again, one of the low water cutouts should be manual reset only -- that is, once it trips you or somebody has to go down there, find out why it tripped, and reset it -- having fixed the problem. The other one should be automatic reset -- and the easiest one to do that with is the McDonnell Miller, since it doesn't have a manual reset option. Therefore, the Safguard should be manual.

Hope this helps...

rgargoum

Thank you both for your responses. Both are helpful. I have downloaded the literature for my equipment.

It appears that the VTX is wired to the cycleguard, and the sensor is at slightly higher a level than the MM.

Yes my boiler was overfilling during the winter due to the LWCO setting and likely slow returns (100 year old house).

Question:

Does the time-delay setting on the VTX cancel the addition of water if the level returns to normal within the time delay period?

Jamie Hall

"Does the time-delay setting on the VTX cancel the addition of water if the level returns to normal within the time delay period?" Yes -- that's the whole idea.

Using the McDonnell Miller's switches (the way Cedric's is set up) is almost ideal in many ways, as the MM is naturally somewhat damped, and there is an inch or two between the signal to the autofeeder and the low water cutoff. End result -- odd bounces and so on don't trip the feeder, but sustained level below the feed point does -- before the low water cutoff gets annoyed.

I think if I were using probes -- which don't, I think, have a differential between feeder signal and lwco -- I'd want to have three: autofeeder signal, an inch lower autoreset lwco, and an inch above absolute minimum a manual reset lwco. But that's me...

EBEBRATT-Ed

@SteamingatMohawk

Regarding pressure controls what I believe the code say is every boiler is supposed to have 1 an operating control and 2 a high limit control.

Normally in residential the thermostat is considered the operating control and the pressure control is the high limit. This in my opinion is fine as long as the boiler does not "normally" build pressure such as ok maybe coming out of night set back it builds pressure and trips the pressure control once a day but usually runs on the thermostat. If the boiler builds pressure most of the time it should have 2 pressure controls 1 auto reset and one manual reset in my opinion

On commercial it is common to maintain constant steam pressure especially on large boiler so two pressure controls are always required. In MA. anything over 200,000 btu requires 2 pressure controls

Jamie Hall

Completely agree on pressure controls. One of the perennial sources of confusion here on the Wall is confusing a pressuretrol used as a safety with a pressuretrol (or better, a vapourstat) used as a control.

IMHO -- but I'm a conservative bloke -- I'll go one further than @EBEBRATT-Ed on this -- as I have on Cedric. The pressure control is a vapourstat, which is intended to keep the pressure between 4 ounces and 7 ounces (doesn't have much work to do -- Cedric and his radiation are almost perfectly matched). Then there is a pressuretrol (automatic) with a cutoff at 1.5 psi. Then there is a manual reset pressuretrol and 5 psi. Both of those are safety devices, not operating controls.