New Gas Steam boiler short cycles

Gaz

There's a bushing at the start of rent boiler that looks like it reducing the outcoming pipe which would be 2 1/2 inch.

reggi

Then you have to be pumping more steam into your system then it needs after it gets boiling and on it's way to fill the radiators , Are all the radiators opened ? All the traps working? Do all the radiator risers get hot ? Maybe your packing air somehere... Even if you don't use some rads turn them on at least to see if they're causing a airlock in your system..If it could take 30 minutes of steaming there has to be something "clogging" up that is open when it's cold

neilc

has main venting been discussed ?

Gaz

One side has 2 gorton #2 vents.
The other side has 1 gorton #2 vent. This install has improved the initial run time from 30 to 40 minutes. 

Gaz

I will check the system tomorrow.  
Reggi did you see the pictures of my pipping?  

reggi

Gaz said:

I will check the system tomorrow.  
Reggi did you see the pictures of my pipping?  

I would agree on the many comments already but especially with @nde way back on the first page about the 

Now it looks like the steam/water carryover is slamming straight up into that first main vs carryover to the equalizer. It there banging and/or one main heats up way faster? If so that main is getting too much steam and locks out on pressure while the other is probably not getting enough but keeps calling.

Just imagine you are a droplet in that boiler and as you fight through the oils to break free you're getting knocked around with all the turbulence around you until you finally get dislodged and out... which pipe are you going to take? The one straight up or are you going to make a 90 and another 90 to be on your way? And don't forget you probably were tossed straight up to begin with... so which pipe gets hot while the other stays cool ?

Something along those lines.. your radiators operating comes first.. then you back track and follow the heat.. from there you'll see that the problem has already been addressed by someone over these pages.. there's only so many solutions to a problem..

AdmiralYoda

Gaz said:

One side has 2 gorton #2 vents.
The other side has 1 gorton #2 vent. This install has improved the initial run time from 30 to 40 minutes. 

You would probably still benefit from more main venting. 610 sqft of steam is alot to vent. An antler of 4 #2's on each main or two Barnes and Jones Big Mouth vents.

If you have a few long risers it might not be a bad idea to vent those too.

That near boiler piping is not going to help you at all. Have it re-piped to meet (or exceed) the manufacturer's minimum requirements.

STEAM DOCTOR

Get a manometer and check the gas pressure. Over fired and under fired is not just a factor of tube numbers.

STEAM DOCTOR

Maybe manifold pressure on Old boiler was two inches of water column and new one is four and a half inches of water column

STEAM DOCTOR

You mentioned that skimming didn't help but adding Scout did help. That would lead me to believe that you did not skim properly. 

STEAM DOCTOR

And just confirm that the pressuretroll is actually what's shutting the boiler. Have a wire, stripped at both ends handy. Sounds like pressure related but always good to confirm. And 2.5" piping is too small. And that's with a a proper header. 

STEAM DOCTOR

And lets back up to step One. Even if everything seems to be working 100% properly, the original installer should still repipe that boiler. If you bought a brand new car that was for the most part driving properly, but just so happened to be getting 8 miles a gallon, you would be entitled to rectification or replacement

Gaz

Will repipe it one day myself but will have a plumber come by with a manometer.
With that wire you mentioned Steam doctor do I jump the pressutrol?

109A_5

Gaz said:

With that wire you mentioned Steam doctor do I jump the pressutrol?

Yes and the boiler will fire back up as long as the jumper is closing the circuit across the open pressuretrol switch. The pressuretrol opens (shuts off) the control circuit when the pressure exceeds the settings.

STEAM DOCTOR

Gaz said:

Will repipe it one day myself but will have a plumber come by with a manometer.
With that wire you mentioned Steam doctor do I jump the pressutrol?

Why not the original installer?? This is an installation defect. 

Gaz

Fly by night

Gaz

Question,
Normally how long does it take for the returns to start warming up.  Mine stay cold for an hour before any change.

Gaz

Could a partial or full blockage on the wet return cause short cycling?

nde

Yes wet return partial block could be the issue. Would explain why the water drops near end of cycle and pressure build. When you opened the clean out was it before or after the hartford loop? Mud collects at the low spot before the HL so a cleanout there is a must. The cleanout after the hartford loop (if there often at base of equalizer) will not flush wet return blockage. If you have no cleanout then only real way to check is to cut the return open and replacing the bottom section.

In a proper setup your mains should start warming in 5 minutes and rads should start warming 5-10 minutes and at fixed temp on therm the cycle should run 25-35 minutes. I had a 50% oversized boiler for years and with proper piping and venting it would still take 45 minutes to build pressure to even 1 lb at which point your rads vents are all screaming and temp swing is probably 5+-.

KC_Jones

nde said:

Yes wet return partial block could be the issue. Would explain why the water drops near end of cycle and pressure build. When you opened the clean out was it before or after the hartford loop? Mud collects at the low spot before the HL so a cleanout here is a must. The cleanout after the hartford loop (if there often at base of equalizer) will not flush wet return blockage. If you have no cleanout then only real way to check is to cut the return open and replacing the bottom section.

In a proper setup your mains should start warming in 5 minutes and rads should start warming 5-10 minutes and at fixed temp on therm the cycle should run 25-35 minutes. I had a 50% oversized boiler for years and with proper piping and venting it would still take 45 minutes to build pressure to even 1 lb at which point your rads vents are all screaming and temp swing is probably 5+-.

100% no. The wet return has nothing to do with building pressure. Pressure is a function of boiler size, to system size and venting capacity, until all the vents are closed. After all vents are closed it's a function of boiler size to system size. As far as the times you listed, that varies by system. Some guys on here heat their main in 90 seconds, on mine it's never more than 3 minutes, some maybe 5 is about right. Run times can vary wildly depending on outdoor temps, system size, etc. As far as building pressure, first, you don't want to, if you do it's an indication that something is wrong, in your example a boiler 50% oversized. My system never sees more than about 4 ounces and by the numbers that's about 10x more than is needed to heat the building. I know my boiler is slightly oversized, but is sized "correctly" by the classic method that I, at this point, don't agree with. I would have put in the next size down if I was doing it over again.

In the case of the OP, you will not get it to run right until it's piped properly. If you're looking for some magic bullet to get this running better temporarily have at it, but to my eye I see no way of getting around that incorrect piping. It's a restriction right at the boiler, no way around it. So either live with it until the re-pipe or continue to beat your head against the wall trying other things that won't make a significant impact, or zero impact.

If you think the wet return is clogged, that's a situation that should be addressed, but it has nothing to do with the pressure and short cycling on pressure.

nde

I agree is needs a repipe but that cleaner could have carried up into that straight pipe main and flushed the crud down. A almost closed return would build pressure as water backs up. The fact venting helped but now water is disappearing at end of cycle suggests clog. It all points back to bad piping but is a possibility that once repiped you still have a partial clog if the cleanout is not at the lowest point before HL

ChrisJ

nde said:

I agree is needs a repipe but that cleaner could have carried up into that straight pipe main and flushed the crud down. A almost closed return would build pressure as water backs up. The fact venting helped but now water is disappearing at end of cycle suggests clog. It all points back to bad piping but is a possibility that once repiped you still have a partial clog if the cleanout is not at the lowest point before HL

How would it build pressure unless the water is backing up to the point it's restricting flow of steam into the radiators? The radiators are the condensers keeping pressure down, not the boiler return.

I'd expect some serious hammering from that.

ethicalpaul

How is the water disappearing in the gauge glass? Is it slowly and steadily dropping? Or does it get to a point where all of a sudden it drops?

Gaz

Its drops 1.5 inches after 40 min of running and then the pressure rises and boiler starts short cycling.  Water does come back up again.

Gaz

The drop is slowly dropping maybe after the 35 min run. 

Gaz

Could it be the straight shot into the one particular main the water is shooting up there.  I hear a little water gargle coming from the radiator vents.
The radiator are pitched well.  

ChrisJ

Why is your boiler constantly running for 35-40 minutes at a time in November - early December?

Jamie Hall

It could also be a pipe which was supposed to be a wet return but which isn't any more because the boiler water level got lowered when it was replaced or someone raised a bit of pipe to get it out of the way. Look around the place with a good level.

Gaz

Gaz

According to my boiler manuel it shows I only need 1 riser.  Do you think 1 is really sufficient?

pedmec

This thread is the biggest waste of everybody's time. Nowhere is there an exception to piping the boiler incorrectly and expect to get a properly running boiler. if you don't change the "near boiler piping" then everything is just a guess. Incorrect "near boiler piping" causes a lot of problems with a steam boiler operation that can mask itself as being caused by something else. Correct the "near boiler piping" and then get back to us. And flush the chemical out of the boiler. Chemical imbalance causes issues too

109A_5

Hello @Gaz,
Is it 3" pipe ? I thought you determined it was not.

Gaz said:

The pipes coming out of the boiler are 2.5 inches diameter vs 3 inch requirement. 

Two would be better (if possible) since it slows down the steam velocity leaving the boiler.

Dan_NJ

Nothing I see in the manual about more than 1 riser needed, but 3" is required for your GSA-238. It may seem like it's only an extra half inch but 3.0" works out to around 45% larger opening vs the 2.5" riser.

EBEBRATT-Ed

@gaz

When something is installed wrong like your boiler NO ONE has a crystal ball or a majic wand to say it will work if you fix this or that. The MFGs spend a lot of time testing (we hope) and coming up with specifications for how to pipe their boilers.

With some systems and boilers, they can be piped horribly wrong and work quietly and make steam, but there is no way to know how this "experiment" will come out until it is put into service.

Many on here like oversized risers an headers and more risers than the mfg calls for as well as drop headers etc etc which is fine if the customer will pay for those additions.

Bottom line is if the installer follows the MFG piping drawing (which is the minimum standard) that is in the manual for every steam boiler the job will work. If someone wants to exceed the MFG minimum that is fine.