Is my steam boiler short cycling?

jdp1219

Can anyone tell me if my steam boiler is short cycling from this example:

Room temp is: 70 degrees
Lets say I up the thermostat to 73 degrees

Once the thermostat calls for heat, it takes about 5 minutes for the thermostat to hit 3.5 psi in which the pressure troll cuts the boiler.  Then it takes about 2 min for the pressure to drop and the boiler to kick back on.  The cycle is about 7 minutes.  Keep in mind that this is not from a cold start. 

This will take place about 8 to 10 times until the thermostat is satisfied.

Did I give enough information here?

delcrossv

Is your system one pipe or two pipe?
Under normal operation , the boiler shouldn't be cutting out on pressure. (and 3.5 psi is rather high)

ethicalpaul

"Short cycling" is really not a very useful term in steam boilers in my opinion. So I will set it aside.

It sounds like your boiler is oversized and cycling on pressure more than is desirable.

1. What is your main venting situation? Good operating main venting can go a long way toward helping this issue.
2. How does it perform during a normal call for heat (not from a setback as you described)?
3. You said "thermostat to hit 3.5psi" but we all agree you must have meant "pressuretrol"...as @delcrossv said that cutout is too high. Of course if you drop it to where it should be, you'll see even more cycling, but it is still better than running at 3.5psi.

jdp1219

My pigtail got clogged and I live in NJ so i had PSEG worry free come to replace the pigtail and pressure troll.  They set it to 3psi cutout and 1psi differential.

@delcrossv It is a two pipe system.  There are two pipes going out that go to two side of the house and they both have a main vent on them. 

I also have a hot water loop (with a circulator pump) that heats the basement.  I don't know if you need to know this information 

1.  @ethicalpaul How do I check what my main vent situation is like?  I can take pictures if that helps.

2.  On a normal call for heat the pressure troll never kicks in.  Let's say ai have the temp set to 73 degrees and the thermostat drops down to 72.  The boiler fires up and satisfies the thermostat without much pressure at all.

3.  Should  I change it to cut out at 2psi and differential at .5?

If I send pics of the system and radiators, would you be able to tell me if the boiler is oversized?

pecmsg

Pics of the boiler piping from different angles. Try and get all the piping in 1 shot.
Rads also help.

EBEBRATT-Ed

If the boiler does not build pressure on a "normal" call for heat leave it alone. Reducing it to 2 psi will give you more short cycling.

Keep the setback to a minimum.

Post some pictures of the boiler and piping and radiators

ethicalpaul

Ahh welcome to the forum, fellow NJ resident! Unfortunately you must not have gotten someone from PSE&G who knows steam. The Pressuretrol should cut out at about 1.5 and cut in at about .5 (a 1 psi differential). There are different ways they are set so I can't be more specific than that without seeing it.

Plan for the future to find a real NJ steam contractor such as @clammy or @EzzyT. I do know one good guy who abandoned his NJ contracting firm to work for PSE&G but you apparently didn't get him.

Are you sure it's a two pipe system? Your description is not the definition of a two pipe system. How many pipes go to each radiator? That is how you tell.

It sounds like you know what main vents are, that's a good first step. Yes, please post pictures of your two main vents. That will give us a good idea. You can search for "main vents" on this forum to find 1000 threads about how to determine if your main venting is good and how to improve it or people will tell you in this thread.

Since you don't hit the pressure limit on a regular call for heat, you are possibly in good shape. See if it is still that way after you reduce your pressure limit to 1.5 PSI. Although I'm a bit dubious of this since you said that it cuts out at 3.5psi after 5 minutes. How could it satisfy a normal call for heat in less than 5 minutes?

We won't be able to tell if your boiler is oversized from pictures but yes send pics of your boiler and the piping near it because we like to see it. Take the pics from about 7-10 feet away from different directions and zoom out so that all the nearby pipes are visible floor to ceiling. (spoiler alert: we already know your boiler is oversized because otherwise it wouldn't cut out at 3.5psi after a few minutes)

ethicalpaul

PS: I watched your video about skimming. You already know more about steam than a lot of plumbers. Why didn't you clear your pigtail yourself? You definitely can do it. I saw your near boiler piping, it looks pretty good, you are fortunate there, it looks like your plumber actually looked at the instructions.

PPS: the skim port is to the left of the pressure relief port that you were using. You can skim a lot faster out of that larger port. You can get the black pipe fittings at Home Depot or SupplyHouse.com. Set it up just like you did on the pressure relief valve, but with the larger pipe size.

jdp1219

@pecmsg @ethicalpaul This might be easier!  Took a quick video of everything.  It also looks like I have a one pipe system and not two.  This is a picture of the radiator that is being blocked by the sofa in the video.  Please keep in mind that I am a first time home buyer who only learned about steam boilers last year.  The house came with a 25 year old Peerless steam boiler that I discovered was cracked after a few months after I bought the house.  here is video:https://youtu.be/Qbwn55DRhho

ethicalpaul

OK nice video. You're not in too bad of shape I think. It can be hard to tell with the finished basement though.

Here are the things I noted:
- Your pressuretrol is fine. You said it was set for 3.5PSI cutout but it looks more like 1.5 which is good.
- Your boiler supplies 354 sq ft of steam so you could size all of your radiators to see what their sq feet of EDR is, add them up and see how it compares to 354. Get Dan's book from this site called The Lost Art of Steam Heating. It will help you size the radiators and learn so much about how your system works. You are a homeowner now with steam, you need to know this stuff
- You have two parallel-flow mains (assuming the second one has a return on the ground like the one in your garage), each with a single Gorton #1 vent. Most will say you could use more main venting, and they wouldn't be wrong but it will be hard to add more I think. At least make sure they are each working and they will serve you pretty well.
- Your mains are copper which is weird, but if they are pitched appropriately they should do OK for you.

How to tell if the main vents are working?

Bump up your thermostat a couple degrees.
See the boiler start to fire.
Start a stopwatch on your phone.
Feel on one of the mains where the steam is going.
Keep following it as best you can given your finished basement.
Move on to the main vent.
See if you can feel or hear air escaping from it.
Keep feeling the pipe below it to see when it gets "steam hot"
See if the vent closes once it gets "steam hot"
Stop the stopwatch.
Tell us how long that took
That will give us an idea.

You can repeat the whole process with the main vent removed if you feel confident removing it. You would then compare the two times to see how much less time it takes for the steam to get to the vent with the vent removed to get an idea of if you have enough venting. The goal is to fill the main quickly with steam and then let the steam slowly fill the radiators.

jdp1219

@ethicalpaul I definitely could have cleared the pigtail myself (will do it next time).  I am def going to get that book also!

I am also going to do the vent test like you told me to do so once I get back home.

Quick question.  My other buddy who works for PSEG has helped me out alot.  He told me to remove water from the boiler about every 3 weeks to make sure the low water cutoff is working.  I do this religiously.

I also vaccum the burner area once in a while.

Is there anything else I can do to maintain the boiler?

Anyway to keep the pigtail from clogging?

As far as the skimming.  The manual for some reason said to do it from the relief valve.  Will I ever have to skim again?  Also, should I run the hot water loop while skimming?

Dan_NJ

jdp1219 said:

My other buddy who works for PSEG has helped me out alot.  He told me to remove water from the boiler about every 3 weeks to make sure the low water cutoff is working.

Your low water cutoff is a probe type, unlike the older float type that should be flushed weekly. I think testing it every three weeks is a bit much, unless it's not been serviced in a long time or for some other reason is suspected to be unreliable. I would have to drain something like 1/3 to 1/2 of the water in my boiler to get the low water cutoff to trigger and I'd rather not be adding that much fresh to my system mainly due to extremely hard water.

ethicalpaul

Yeah I test my probe type LWCO once a year.

You want to minimize the fresh water you introduce into your boiler. It comes with a lot of oxygen that can increase corrosion inside your boiler. Many of us also add a little treatment such as Rectorseal 8-way to get the PH of the boiler water up to 10 or so. This PH greatly reduces iron corrosion.

You can vacuum out your burner area every 3 years and be way ahead of 90% of everyone else

You probably won't have to skim any more once the oil is gone. Rather than running your water loop while skimming, I'd just probably skim a couple times about a month apart...that will give all the oil a chance to rise to the high points.

Once a year, drain 1/2 to 1 gallon of water off the bottom of the boiler (using the boiler drain) to flush out some of the mud that builds up.

You may or may not be able to flush some water out of your wet return (the pipe that runs along the floor) depending on how they set it up for you, but basically mud will collect in all the low points and it's nice to be able to flush some of that out every year or two.

Here are a couple screenshots from the manual. The one shows the skim port is the 1" port to the left of the PRV. The other one shows where you can install valves on the return pipes to allow easy flushing

jdp1219

@Dan_NJ @ethicalpaul

Thanks!  I will not test the LWCO so much any more.  My system loses a gallon about every 2 weeks.  Is this normal?

When you say to remove a gallon from the boiler drain, I assume that's the same drain I use when normally removing water from the boiler?  Here is a picture of the drain I am talking about.



I definitely want to add the the treatment to the boiler.  Should I add it through the relief valve port?

neilc

unless you're treating a specific known water condition,
DO NOT add treatment,
run on straight clear water,

your returns, are they under the slab ?
or above where you can see them for leaks?
under slab returns can be prone to leaking, and may be your water loss issue,
and adding fresh water to the boiler regularly is bad for the boiler,

JUGHNE

There is a 1" skim port to the left of the relief valve. Has a cap on it.
I would add length to that with a 90 pointing down to skim with. Add a ball valve is you wish, but unnecessary.

ethicalpaul

Yes that looks like your drain but it is piped kind of strangely, hard to tell.

you have dueling advice I see with the treatment, but I consider 7ph (neutral) to be a condition that requires treatment.

I would add a nipple, a valve and a tee to your 1” skim port then you can use that to add stuff. Just add enough to get the ph up, not the whole bottle 

a gallon every two weeks tells me you have some leaks, probably steam leaking from a vent or valve. 

jdp1219

@ethicalpaul Sorry, have been away for the holidays so still haven't gotten a chance to time the main vents yet. 

I do have another question.  Some of the radiator vents (I have Varivalves)  have drop of water coming out of them.  Any idea why?  The radiators are pitched properly.

ethicalpaul

I would have to see the drop of water to know (and how often it's dripping). I'm not very familiar with that vent in use so I don't know if it's prone to dripping.

Wherever steam condenses, water will form, that includes in a vent. Vents obviously also vent air out, so sometimes they will push a little water out with the air, but with good steam production and nice slow radiator venting this isn't normally an issue.

Hap_Hazzard

ethicalpaul said:

Wherever steam condenses, water will form, that includes in a vent. Vents obviously also vent air out, so sometimes they will push a little water out with the air, but with good steam production and nice slow radiator venting this isn't normally an issue.

My system produces pretty dry steam, but from time to time I still find a vent here and there with the sniffles. When that happens I just take it off, shake the water out and put it back. One of these days one of the vent manufacturers will get smart and start putting little drain petcocks in the bottoms of their vents.

Hap_Hazzard

ethicalpaul said:

you have dueling advice I see with the treatment, but I consider 7ph (neutral) to be a condition that requires treatment.

I'd be inclined to follow Paul's advice on water treatment. He's not a pro, but he's put a lot of time and thought into dealing with water quality, and he lives in Jersey and is probably using water with chemistry that similar to yours.

jdp1219

@Hap_Hazzard Thanks!  @ethicalpaul It happens a few times a day from the same radiator vent.  It's usually a few drops and makes a low gargling sounds for a few seconds.  I'll try to get it in video.

ethicalpaul

Sounds good. If your boiler is producing wet steam (carrying boiler water into the steam lines), that could also be putting a lot of excess water into your system which can possibly manifest as water at the vents.

Or there could be an issue with the supply piping to that radiator.

If everything throughout the system is pitched correctly and the steam production is good, I daresay one should never hear gurgling.

jdp1219

@ethicalpaul Is there a way to figure out if I am producing wet steam?  I may have misidentified the sound coming from the radiator vent.  Its more of a slight bubbling sound that last for 3 - 5 seconds rather than a gargling.  However the radiators did gargle last year before I skimmed the boiler.  They used to sound like they had watwr running through them 

Also, is it normal for the thermostat to stop calling for heat 1 degree higher than I set it on?  For example if I set it to 73, it doesn't stop calling for heat until it reaches 74.  What ends up happening is that the room temp will go up to 75ish I guess because it cuts out at 74 but the radiators are still hot enough to warm the house a bit.

Jamie Hall

The radiator sound is more or less normal -- steam may be a little wet, but not enough to worry about I'd say.

As to the thermostat --what make and model is it? Various ones behave rather differently, but there may be a way to subdue it at least a little.

jdp1219

@Jamie Hall  Here is a pic of the thermostat.  I also tried to get a video of the vent on the radiator.  This vent is old and is on a larger radiator that is on the second floor of the house.

link to vent video:  https://youtu.be/56or2WMViGI

You can see a small drop of water.  I started recording after it trickled out of the slit.  Same thing happens on the newer vents downstairs.  I'll get 2 to 3 drops at the most.

ethicalpaul

jdp1219 said:

@ethicalpaul Is there a way to figure out if I am producing wet steam?  I may have misidentified the sound coming from the radiator vent.  Its more of a slight bubbling sound that last for 3 - 5 seconds rather than a gargling.  However the radiators did gargle last year before I skimmed the boiler.  They used to sound like they had watwr running through them

Sounds like you definitely had wet steam before. It can be hard to tell for marginal cases. I put sight glasses on my near boiler piping so I can see it, but I'm the only one I know who has that unfortunately.

Here are the other ways you can tell, some of which you have already experienced:

1. Water level drops dramatically during call for heat (because gallons of water is getting carried into the main)
2. "whooshing" or "rushing" sound can be heard in near boiler piping (I only learned this from watching my forced-wet-steam experiments)
3. Main vent(s) shooting water
4. Radiator vents shooting water
5. Radiators make sloshing or gurgling sound (can also be caused by incorrect pipe pitch to those radiators)
6. Water hammer at certain times of call for heat (can also be caused by incorrect pipe pitch in main or radiator supply piping)

Here are some of my videos where you can see wet steam:

- This one was my old boiler when I hardly knew anything: https://www.youtube.com/watch?v=WSRvvNQ5WLc

- Still my old boiler but I knew quite a bit more: https://www.youtube.com/watch?v=Si-FoRQVIpA

- My new boiler when I knew everything haha (for this one I purposely put oil into the boiler to see the wet steam that resulted): https://www.youtube.com/watch?v=jvt8qxBaRJU

ethicalpaul

Regarding your vent video, it looks like it's just taking a few seconds for the vent to close against the steam. As long as it does in fact close and the steam stops escaping shortly after arriving at the vent, you're OK

Jamie Hall

Hmm... I can find no information on that thermostat. Do you have the manual? Or did PSEG just come out, whack it on the wall and say there! Good to go!?

jdp1219

@ethicalpaul Those videos are amazing.  I definitely had wet steam last year but not anymore.

@Jamie Hall Yes, PSEG put slapped it on and left.

Jamie Hall

Wonderful. It's a bit of a pain -- but if they didn't leave the manual, you have no good way of figuring out how to fix the problem. Which may not be fixable with that thermostat anyway. You could try going to a big box and getting one of the less expensive battery operated Honeywell or Emerson thermostats -- some of which are programmable -- and trying that instead, if you feel up to swapping thermostats.

Chris_L

Hmm. When I Google the make and model of that thermostat, as shown in the photo, I get this hit: https://www.supplyhouse.com/ICM-Controls-SC1600L-Non-Programmable-SimpleComfort-Heat-Only-Thermostat-w-o-Fan-Switch-Single-Stage

Looks like the same one to me. You can download the User Guide there. It describes how to adjust the temperature differential, which might correct the problem of the thermostat turning off too late.

ethicalpaul

Nice find. Here is how you set it. Pretty funny actually. Pull the battery and when you put it back, you have some time to set the differential

The default temperature differential is 1°. When your room temperature varies by 1°F, the thermostat turns on your system. If you notice your system turning on and off too frequently, increase the temperature differential.
1. Reset the thermostat by removing batteries for 10 seconds and then reinstall them. 2. For the first 10 seconds of operation, the temperature differential is displayed.
3. Press the down or up button to select desired setting.

jdp1219

@ethicalpaul Thanks for the instructions!  Any recommendation on what I should set the differential to? 

Also, my upstairs radiator makes this sounds once in a while.  Its not water hammer but its the sound that usually leads up to water hammer.  However I dont get water hammer.  I remember the sound from last year when I did get water hammer.  Any ideas?

:  https://youtu.be/IpXsPhDvDPk

ethicalpaul

I'd probably try 1, 2 and 3 to see how they each performed for a week each.

It'd be nice to know what the tech set it at, but I don't think you'll be able to see that. He might have set it higher if he knew you had steam.

I think the differential is the more logical way to think of what other thermostats call "cycles per hour". I think they invented "cycles per hour" in a misguided effort to make the homeowner ask fewer questions or something.

"cycles per hour" always bothered me because it implies that a system is actually timing the cycles and spreading them out or something when in fact (to my understanding and belief) the thermostats are really just using differential to determine when to call for heat.

Steam and hot water are usually set at 1-2 "cycles per hour" which I think corresponds to higher differentials than you'd see in a forced air system (maybe 2-3 degrees).

Personally I set mine on the low side for differential but you don't want the whole system to have to get hot to just heat up the radiators a little bit (in my opinion), so I don't go too low.

This is a long way to say "try 2 degrees and see how that works and how comfortable it is"

Regarding the sounds: Yes, that sounds like there is something going on, possibly water getting carried through parts of your system.