DID i CAUSE THIS?

Rick_41

A few years ago I moved into a pretty big house. About, 4,800 sq ft,
Only my wife and I live here and over this winter my wife had to be gone to take care of a relative, so I shut off one radiator on the first floor, and 5 of the seven radiators on the second floor and the 2 of the only 2 on the 3rd floor which is only used if we have guests over,

I shut the doors to rooms with the shut-off radiators to save heating costs.

(this is a gas two pipe system)

So what I'm getting now seems like a short cycle. The thermostat seems to get satisfied, but it seems to take a long time if I turn up the heat.

When I look at the the boiler's sight glass, it runs for a while but after a few minutes the water level dives to the bottom and the LWCO kicks in and it shuts down for several minutes until the level comes up and the boiler turns one again.

So are shutting down these radiators the cause of this?

neilc

shutting down rads and rooms would lead to short cycling, but not as you've described at the LWCO,
rads and rooms would trigger the Ptrol, not the LWCO,

it's more likely issues that are at the boiler,
what pressure are you running?
and when did you service the pigtail last ?
pictures,
one or 2 distant showing the whole boiler, floor to ceiling, so we can see the piping above,
and a close up or 2 of the Ptrol, gage, sightglass, and LWCO

nicholas bonham-carter

What sort of main vents are on your system?
If the main vents are insufficient, or nonexistent, then the radiator vents must step up to a job for which they are ill suited, both to let the air out, and to let it back in, when the burner shuts off. Since many of your radiators are shut off, then the vacuum is slow to dissipate, and steam slow to rise.
This will be more pronounced, especially in recovering from a setback, wasting fuel.--NBC

mattmia2

nicholas bonham-carter said:

What sort of main vents are on your system?
If the main vents are insufficient, or nonexistent, then the radiator vents must step up to a job for which they are ill suited, both to let the air out, and to let it back in, when the burner shuts off.--NBC

They said it is 2 pipe steam so all of the venting has to be through the main vents.

I am certain they are related, just not sure how. Possibly a symptom of an existing problem that was exacerbated by shutting most of the system off.

Maybe something like it is making wet steam and the returns from all of the radiators could return it fast enough to keep the boiler above the lwco but just a few radiators and the crossover traps can't.

Jamie Hall

If we make the assumption that the boiler was the right size to begin with -- a generous assumption -- it is now at least twice as big as it needs to be; maybe more. Even with generous main venting, that will make it short cycle on pressure. It may also lead to some really weird condensate return problems.

There is another problem of which you may not be aware, however, as it usually takes some time to show up: humidity in the closed off rooms. No matter how tight the doors are, there will be some air exchange, and that will bring nice moist air from your living area into those colder rooms. They are likely at or below the dewpoint of that nice moist air, and the moisture will condense on everything in the rooms. This will, eventually, lead to some unhappy mold problems in all fabrics and paper goods which may be in there. It will also eventually lead to damage to the walls and ceilings themselves (drywall goes first; plaster can take a decade or two to be damaged to the point of replacement).

Rick_41

The PTOL is now set all the way down,) a pressuretrol only has cut in,.,0.5
The vent valves are #1 gortons on the return line,..when I got the property, I thought someone here said you can't have too much venting? There was one on each return near the boiler,.So I put 2 more on each return line (total of 6)
The Boiler is a fairly new (I think 4 years old) Smith

I wish I could send a photo,..but I'm a photo idiot and don't have a cell phone that takes pics,..

Nothing has been done to alter the piping since we have been here and it WAS working OK last year.

Do you think I should open all the radiator valves?

neilc

Rick_41 said:

Do you think I should open all the radiator valves?

that's the change that's been made , , ,
it would tell if the short cycling goes away,
or if some near boiler maintenance were required,

there's also something to what Jamie mentioned about leaving the heat too far down in those cold rooms

Rick_41

Yep,..just opened all the valves,
The rooms actually don't get too cold, good insulation in the walls, the 2nd floor where all the shut off radiators/rooms were It doesn't get too cold as there is a good amt of insulation in the walls and the top floor also doesn't get too cold so not much heat loss from the 2nd floor ceiling.
I have humidity gages in all the rooms,..and It's actually very dry (under 19% as low as they register,..)

I guess I will find out,..supposed to be very cold and windy tonite,..

Rick_41

Well , so far it doesn't seem to have an effect so far,.still very shor cycles,.
What if I temporarily put some industrial tape over two of the three vent holes on each return, (The thought of having too much venting,) So I still would have a #1 Gordon on each return line.

Does that make ANY sense to try?

bburd

If anything you need more venting, not less.

EBEBRATT-Ed

It may have built pressure with the radiation shut off and pushed water up into the vents from increased pressure.

You need to find out if the low water cutoff is shutting the boiler down or the pressure control, Theose are the most two likely controls.

Then find out why it is shutting the boiler down

Rick_41

Re more venting, again it had a #1 gordon on each return line,I put 2 more of them on each line,

I notice that when it refills I see on the sight glass the fluid comes down from the top,..is that normal?

I think the LWCO is working correctly as the boiler kicks off when according to the sight glass is very near the bottom (after the boiler is firing for only about 1 minute,..then after about another minute the sight glass shows the levels comes up and it turns on..
Only has a pressertol that has a cut in setting,..I have set it at .05 and moved it to 2,..doesn't seem to make a difference.

neilc

no pictures, eh?
if you're cycling on the LWCO,
ie: the water is leaving, and returning,

the water is either boiling dirty, and getting thrown up into the mains and system, and or the boiler isn't piped properly,
or,
you're not controlling pressure, and water is getting pushed out the bottom, into the returns,
or both,
and both are bad,

without seeing the near boiler piping, or the conditions at the controls, , , ,
there's a pigtail under the Ptrol, has it been cleaned so the Ptrol can feel the pressure the boiler is making?
is the pressure gage on the same side of the pigtail as the Ptrol?
(and you're kinda blind that way if the pigtail is plugged)
or is the gage mounted separately, or teed off before the pigtail?

what pressure are you seeing when the boiler has been firing, or just before it cycles off?

EdTheHeaterMan

The condition of short cycling may have nothing to do with the radiator closings. There may be other issues that have developed this season that have nothing to do with your energy saving idea. It appears that it is time to call a steam heat professional. Look in the "Find A Contractor" link at the top of the page.

One question... Did you save on fuel with more than 1/2 the radiators closed?

Rick_41

I'll try to get someone who knows how to post pics,
The water looks pretty clear on blow downs,..as well as in the sight glass. The gauge looks like its stays at 5 when running for a while,..again the sight glass seems to be filling while running largely from the top.

Rick_41

I can't really tell if we saved much fuel closing down the radiators. My wife took care of the billing in prior years,.and I can't find where she put the old bills.

I had a good old steam guy for another house 7 miles from here, but he has had health issues and no longer works,
I've tried to find someone that knows steam(looked at the reference here) but I'm not confident there is anyone very near enough that would be willing to travel.

neilc

that pressure up at 5 steady = bad,
you're pushing water out of the boiler,

and I missed where you said you turned the Ptrol up,
don't do that, turn it back down, all the way down, back to the 0.5,

does the gage return to 0 when the boiler is off ?

I'm thinking you need to service the pigtail under the Ptrol

Rick_41

Thank you so much! Actually I did turn the pressertrol down to .05 rt before this,..and no,..it doesn't go down to zero,.about to 1-2 when has been off for a while,..does that mean the gauge is bad?

Rick_41

OK I'll get the pigtail cleaned,..

BobC

If you can see water trickling down the gauge glass it means something is in the water that should not be there. The boiler should be drained completely and refilled a couple of times to remove the contaminants from the water, this should be done when the boiler is cool or warm to the touch - not when it's boiling hot.

The pipes and valves feeding the gauge glass should be checked to make sure they are free and clear.

Bob

Rick_41

Thank you Bob,..will do that too this weekend,..question: do you think Rectoseal 8 way boiler additive is good or bad?

BobC

The Rectoseal is fine but the instructions on the boiler often have you putting to much product into a residential boiler and that can cause problems.

If draining and refilling seem to work initially but then it starts to act badly again in a day or two that means thje boiler has to be skimmed to get oils off the top of the water. It should be a nice long skim with a stream of water coming out of the skim tapping the size of a pencil or less.

Bob

Rick_41

Hey,.Thank you again!, I got some things to do, re this,..The pig tail, draining and maybe even skimming,.unfortunately not a good place to drain,..but I'll figure it out,..

tim smith

is water in sight glass dirty? Any chemicals added since new. I would dump boiler at least and refill with fresh water. Ideally you would skim boiler too but not so easy for a novice. We have had our tds too high and chemical companies dosing pump was adding too much chemical. Caused water line problems up the kazoo. Just one of a few things that could cause water line problem.