Basement Radiator Air Vents Spitting Water

johnnydebt2

Recently purchased a new home that has a Weil Mclain gas steam boiler. There are two radiators mounted on the walls in the basement above the water line and are currently spitting water out of the air vents. When the boiler is on, the water in the sight glass is brown. The water in the sight glass drops to where the sight glass will be empty once the boiler starts to reach pressure.

The pressure gauge reads around 5psi when the boiler shuts off. I've been playing around with the pressuretrol by putting the differential at 1 and the cut in at 0.5. However the pressure gauge still reads 5psi before the boiler shuts off.

What could possibly cause the radiators air vents in the basement to spit water? Is this due to the boiler water not being cleaned/skimmed properly? Or is it because of the high pressure?

Any help would be greatly appreciated.

Neild5

Can you post pictures please? If you could take pics of the sight glass and LWCO, the pipes coming out of the boiler and the radiators.

BobC

Does the pressure gauge read zero when the boiler is cool or just warm? Is that gauge on the pigtail with the pressuretrol or is it mounted on a seperate boiler tapping?

The pigtail underneath the pressuretrol might be clogged and that means the pressuretrol doesn't see whats goiung on in the boiler.

In and case 5PSI is much to high, please post pictures.

Bob

nicholas bonham-carter

You probably need a vaporstat, and low pressure gauge, (0-3 psi), as the factory supplied pressuretrol is far from accurate, and when adjusted for its lowest pressure, can disconnect the internal linkage, causing it to become inoperative.
For every ounce of boiler pressure, the level of water in the wet returns will rise 1.75 inches. Depending on the height of those basement radiators, then not many ounces of pressure will be needed to fill the system with steam, and yet keep the water level under control.
Checking the pigtail for obstruction is also indicated.--NBC

johnnydebt2

@Neil5 - Unfortunately I'm not at the house on the weekdays. I do have a picture of the sight glass, skim port, LWCO. I'm also attached a picture of the boiler piping and the problematic basement radiators. Please see the pictures attached.

@BobC - The pressure gauge is a plain 0-30 PSI gauge as required by code and reads zero when the boiler is cool and warm. I don't recall if the gauge was mounted on the same pigtail as the pressuretrol. I will need to check this on the weekend. I believe the pressure gauge and pressuretrol were on separate tappings.

I can take the pigtails off and see if they are clogged when I'm back on the weekend.

@nicholas bonham-carter - Will check the pigtails for obstruction. I would rather not have to spend the money on a vaporstat and a low pressure gauge, but will if its necessary. Is there a way I can check the functionality of the pressuretrol and accuracy of the pressure gauge?

In the event I do that I do need to purchase a vaporstat and low pressure gauge, do you have any recommendations? I've heard good things about Wika low pressure gauges that range in 0-3 psi.

Fred

It sounds like the pigtail may be clogged or the Pressuretrol is way out of Calibration. You don't need a Vaporstat, you need to clean that pigtail and maybe recalibrate the Pressuretrol. Below is the procedure for that re-calibration. Having said that, you do need a 0 - 3 PSI gauge and the Wika gauge is fine. It also sounds like the boiler needs a good skimming if the water acts as you say. Oils on the surface of the water will make it almost impossible for the steam bubbles to break through the surface of the water and that causes the water to push back into the wet returns. Drain and flush the boiler, then skim it properly. There is no rushing a good skim. The few dollars you spend on a new gauge is money well spent, unless you are satisfied with the way the boiler is running now and the on-going added fuel costs due to that inefficiency. I doubt that is the case or you wouldn't be here looking for solutions.
Re-Calibration Procedure:

Inside the Pressuretrol, right below the micro switch, there is a pivot arm. At the end of that arm you will see a screw pin that is activated by the diaphragm at the bottom of the Pressuretrol. If you look very carefully at that screw pin, you will see it actually has a tiny (I mean tiny) hex head on it. It takes a .050 hex wrench and you can turn it clockwise (Towards the bottom of the Pressuretrol to decrease the Cut-out pressure or counter clockwise to increase the cut-out pressure (which none of us want to do but who knows, your Pressuretrol may be really screwed up!). Turn the power to the unit off first. You may find the first attempt to turn that screw a little bit stubborn (relatively speaking) because it has some Locktite on it but it does turn. Don't turn too much, a tiny fraction of a turn goes a long way towards getting it adjusted where you want it (maybe 1/32 inch turn to start with) . You may need to play with it to get it exactly where you want cut out to be.

johnnydebt2

@Fred - Thanks for your input, that was very helpful. This weekend I'll go and take off the pigtail and check if its clogged. Will the pigtail come off using a pair of channel locks? I can't imagine the pigtail to be on terribly tight.

I'll also do drain and refill the boiler a few times to see if water quality improves. I'll test fire the boiler and see if the same conditions occur in the sight glass after checking pigtail and draining. I'll also take note of the cutoff pressure so that I can adjust the sensitivity of the pressuretrol through the hex nut. If the water doesn't improve, I'll proceed with removing the plug in the skim port, and skim cold then hot. I have a pair of pipe wrenches, 18in and 24in to remove the plug on the skim port.

I'll also run to the local plumbing store to see if I can pick up 0-3 psi gauge. Would you recommend a gauge that deals in Ounces per square inch instead? Should we not aim for 10 ounces of pressure for cutoff and 4 ounces of pressure cut in as mentioned in Dan's book? Or is that only possible with a vaporstat?

nicholas bonham-carter

Is this system one-pipe or two?
At least get the gauge from Valworx, only available online,
http://www.valworx.com/product/low-pressure-gauge-25-0-3-psi
so you know what the pressure is. The presuretrol is only vaguely accurate below 1 psi, even with calibration, and depending on the height of the basement radiators, the waterline may be as high as they are.
The gauge, vaporstat, and large main vents if needed are investments, and not mere expenses. They will repay their cost with lower fuel use, and greater comfort and efficiency for years to come. Will you live in this house, or are you flipping it?
The waterline draining down to the bottom of the glass when firing is not normal, and will shorten the life of the boiler.
If the water in the boiler is dirty, with oil on the top, then the boiling is more explosive, carrying water up into the pipes, and rads. The oil floating on the surface can only be removed by skimming, and not by draining, or chemical additives. This process involves several hours of draining off the surface of the water. Draining the water first will only remove any rusty sludge at the bottom of the boiler.--NBC

johnnydebt2

@nicholas bonham-carter - This is a one-pipe system and I intend to live in this home. I have placed an order for that 0-3 gauge that you referenced above. Thank you for that.

I will try to work the pressuretrol for now because the vaporstat is an expensive piece of equipment. But will upgrade it if the vaporstat will solve the issues. I'm leaning towards water quality being the issue with the boiler, along with mis-calibrated pressuretrol. I will also check the leveling of the pressuretrol to see if that is causing the issue.

This weekend I intend to get the water quality up to par by draining and skimming if necessary.

Thank you again. Will update once I get to work on this.

Fred

@johnnydebt2 , I'm pretty sure you will need to do the skim but I would drain and refill first to get all the rust/crud out of the boiler and start the skim with clean(er) water. Set the Pressuretrol to .5 Differential and the Main (white wheel inside the Pressuretrol) to "1". That is about as low as you can get with a Pressuretrol. To get to ounces, a Vaporstat is required but that is probably not necessary, except on certain two pipe vapor systems. Keep in mind the Pressuretrol is a Safety device to keep pressure in control. Ideally the system will satisfy the thermostat before the Pressuretrol is ever engaged. A small pipe wrench or channel locks should turn the pigtail off. Use the gauge in the link that Nick provided above.

johnnydebt2

@Fred & @nicholas bonham-carter - I cleaned up the pigtail, it was indeed clogged with a bunch of gunk. The pigtail came off easily with the channel locks. I ran it under water until all the gunk came out, reinstalled it and put water in it. I drained the boiler multiple times. The water that came out with red, really really red. The water is now clean with the exception of a bit of oil sitting at the top of the water.

I confirm that the pressuretrol is set to 1 PSI differential and 0.5 PSI cut-in. I was not able to get the 0-3 gauge in time to install on the boiler this weekend. The 0-30 PSI gauge now reads 2.5 PSI before the pressuretrol cuts the power to the boiler. The boiler will restart around 1.25 PSI.

The problematic radiator vents no longer spit water. The water in the sight glass remains relatively stable and clear now The water in the sight glass no longer drops like it did before. There were two defective air vents on the radiators throughout the house that were stuck on 'open' position, continuously venting steam. I replaced those as well and they now work.

Providing that the thermostat is continuously calling for heat, the boiler gets the system to a pressure of 2.5 PSI, at which point the pressuretrol cuts the power. It takes approximately 1 minute 20 seconds for the pressure to drop to 1.25 PSI before the pressuretrol restores power to the boiler. The boiler will fire for about 2 minutes before the system reaches 2.5 PSI. All radiators in the house are hot at this moment, and all the radiator vents are closed. I'm assuming that having cycles consisting of 2 minutes of firing and 1 minute 20 seconds for steam to condensate is normal, since all the radiators are all getting steam and providing heat. Can someone confirm that this is not short-cycling? I can't see why it would be, since the boiler is operating effectively to provide heat to the house.

I was not able to remove the skim port cap. I used an 18 inch wrench to grip the nipple and a 24 inch wrench on the skim port cap. As I was trying to get the cap off the boiler was starting to move a bit from my pulling. I stopped at that point as I did not want to break threads on the nipple. Would using some sort of penetrating lubricating oil help to remove this cap? I've attached pictures of the skim port cap along with the boiler.

Thank you all, the issues appear to be resolved, but I would like to skim the boiler to remove the excess oil floating on top of the boiler.

Any help would be greatly appreciated.

neilc

sounds like you're making some progress,

you might be able to dial the Ptrol down a bit more and stay under 2#,

I would still say short cycling in that it's bouncing off the Ptrol settings,
How are you for main venting?

you say you had 2 wrenches on the skim port?
the larger short nipple and cap between the pigtail and sight glass?
that looks tight, as in no room , , ,
or were you after the longer nipple and cap on top of the boiler?

Fred

@johnnydebt2 , sounds like you are making progress. You will need two wrenches to get that cap off of the skim port. One on the cap and if at all possible, one on the pipe behind it. You can use some penetrating oil to try to help loosen the cap.
It does sound like you are short cycling. The boiler may be too large for the connected Radiation. Have you ever done a survey of your radiators and totaled up the EDR? That number should closely match the Sq. Ft. of steam on the boiler rating plate. If the boiler is over-sized, short cycling will occur, especially if you are using set-backs on your thermostat and the boiler has to run for extended periods to bring the house back up to temp. Make sure your main venting is good and that you have plenty of venting on the main(s). That will also help to reduce the short cycling by making it easy for the steam to push the air out of the mains and reduce the amount of time the boiler runs doing that.
It also sounds like your Pressuretrol needs to be re-calibrated so that it shuts the boiler down at the 1.5 PSI you have it set for (White wheel set at "1" plus the Cut-out set at .5). It is a simple process to re-calibrate it if you are comfortable with it. If not, get a service tech in to do it for you. Following is the procedure:

Inside the Pressuretrol, right below the micro switch, there is a pivot arm. At the end of that arm you will see a screw pin that is activated by the diaphragm at the bottom of the Pressuretrol. If you look very carefully at that screw pin, you will see it actually has a tiny (I mean tiny) hex head on it. It takes a .050 hex wrench and you can turn it clockwise (Towards the bottom of the Pressuretrol to decrease the Cut-out pressure or counter clockwise to increase the cut-out pressure (which none of us want to do but who knows, your Pressuretrol may be really screwed up!). Turn the power to the unit off first. You may find the first attempt to turn that screw a little bit stubborn (relatively speaking) because it has some Locktite on it but it does turn. Don't turn too much, a tiny fraction of a turn goes a long way towards getting it adjusted where you want it (maybe 1/32 inch turn to start with) . You may need to play with it to get it exactly where you want cut out to be.

Jamie Hall

Just to reassure you -- with all the radiators hot, the cycling you are seeing on pressure is quite normal and indicates that the boiler is only slightly oversize. No change indicated.

You're doing fine!

johnnydebt2

@neilc - I can try to dial down the ptrol to below 2, I have a hex wrench and located the black hex screw to do so. I didn't have the time to do yesterday but can attempt to do that. If I dial the ptrol down, the boiler will still be bouncing off the ptrol settings as it's now lower.

I had 2 wrenches on the skim port. I did this with the pig tail off so it wasn't in the way. I had an 18inch wrench on the nipple and a 24inch on the cap. The 18inch wrench barely fit between the the cap and the boiler casing. See attached picture for clarification.


See attached picture for clarity.

@Fred - Thanks, I'll try to get some penetrating oil on to loosen it a bit. If that doesn't work, would heat from a torch help to loosen it?

I will also attempt to calibrate the ptrol with a hex wrench.

I have not calculated the total EDR, the boiler may very well be over sized. I will try to do measure the radiators on my next visit. I can't quite access the main pipes to assess the venting as the basement is finished and the mains are above drywall ceiling at this point. I can see one main vent that is attached to the return line that is feeding the basement radiators. The venting hole on that vent is small, perhaps I can upgrade this to a larger vent (providing there is space to put it on).

What is the exact definition of short-cycling if I may ask? In my situation if the boiler is oversized, it will bounce off ptrol settings but the radiators will all receive heat. In this case is there an efficiency issue?

Thank you for any help.

Fred

A little heat on that skim port may help but be careful (as I'm sure you know). Short cycling is when the boiler shuts down on pressure, rather than the Thermostat and does so multiple times during a heating cycle with short periods of time between on /off cycling to allow the pressure to drop to the Pressuretrol Cut-in pressure.

johnnydebt2

@Jamie Hall - Thank you, I think that puts my mind at ease. I wouldn't know how to correct an over-sized boiler besides contracting with someone to down fire it or replacing the whole unit.

@Fred - Thanks, will try first with some penetrating oil then if that doesn't work, I'll try with some heat. The boiler was behaving in a short cycle because I had set the thermostat to call for heat while testing the system. The thermostat has a minor setback so not sure if there is going to be a lot of short cycling behavior.

Do you have any recommendations on resolving the short cycling or should I just leave it?

Fred

The best way to minimize the short cycling is to eliminate any set backs and to have very good Main venting. Do calculate the radiator EDR so you will know exactly how over-sized the boiler may be but if you only see short cycling on very cold days (design day or below) I wouldn't worry to much about it. If it happens on every heating cycle, once you know the difference between the connected Radiation and the boiler rating, down firing or a two stage gas valve may be appropriate solutions. Both require a good tech with combustion analyzers to set them up properly.