Boiler overfiring - new pressuretrol did not solve the problem


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Old 01-23-14, 07:28 AM
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Boiler overfiring - new pressuretrol did not solve the problem

I moved into a house recently with a steam boiler (Utica brand, circa 2003). Water in the sight glass was full (above recommended water level), and when the t-stat called for heat the boiler would fire continuously. Called a steam tech, showed me how to drain some water, then fired the system back up. It still never shut off when the t-stat called for heat. Replaced pressuretrol and clogged tube going to pressuretrol and no difference - boiler will fire for hours at a time and never shuts off. I monitored the natural gas consumption and this consumes 1 therm of gas per hour (roughly $1.10) that the boiler is on! The tech came back and says that he thinks there is a piping issue because the steam is not creating pressure, but I disagree because all the radiators in the house (2 story, 2000sf) get very hot, and after opening the system to replace the pressuretrol & pipe the air vent thing (the little pointed thing on the other side of the basement on the piping) pushed out lots of air for a while (but not steam) under what I would consider to be more that .5 psi. The pressuretrol is set to the lowest setting (.5 psi) and the wheel inside is set to 1. What should I do next?
 
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Old 01-23-14, 08:55 AM
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Hi and welcome...

Well if the pigtail for the pressurtrol is clear its either a wireing issue or the gas valve may be faulty..

While its running and you have the issue turn off the emergency switch for a moment then switch it back on.. Does the boiler fire back up when you doe that?

Let us know...

And be careful... Although the relief valve will blow off at 15 psi and runaway steam boiler can be dangerous and explode if the relief valve is not working... Also if it dry fires and cold water is introduced it can be a recipe for disaster...!!!!
 
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Old 01-23-14, 09:24 AM
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I took off the cover to the pressuretrol and moved the piston so that it would activate the cutoff switch. The switch engaged and the boiler stopped firing so I assume that means the pressuretrol is working as intended. I do not have a visual pressure gauge on the unit, but I noticed that when the repair tech replaced the pressuretrol that the pigtail pipe leading to it was replaced with a straight pipe - could that be affecting the pressure registering at the pressuretrol?
 
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Old 01-23-14, 10:18 AM
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pigtail pipe leading to it was replaced with a straight pipe
Yes thats OK I believe.. The pig tail is there to catch the crap so it does not contaminate the pressretrol from what I know... IMO I would want a pigtail otherwise the pressuretrol wont last too long....

Did you try cutting power and then reapply to see if boiler cuts off when in runaway?

And your saying when the t stat is satisfied the boiler will continue to fire???
 
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Old 01-23-14, 10:23 AM
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Yes thats OK I believe
Ummm... no, it's not.

The pigtail is there to prevent steam from getting to the control.

You want/need a proper pigtail on that control!

Don't run it long like that or you'll be buying another.
 
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Old 01-23-14, 10:44 AM
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I thought I should have a pigtail there -- I will contact the technician and have that corrected, definitely. The boiler always shuts off when the thermostat is satisfied, but it will run for hours when trying to heat up the house in the morning and the t-stat calls for heat. Any idea on why there isn't enough pressure building up for the pressuretrol to cut off? I find it hard to believe there's less than .5 lb pressure in the system.... I will try the emergency switch but I'm not quite sure what that is? But since the pressuretrol correctly shut down the boiler firing when I manually engaged it I don't think that there's a problem with wiring anywhere

When the repairman last left (after installing the pressuretrol) he said he though there might be a piping problem preventing the boiler from building up enough pressure to activate it -- does this even sound reasonable? Like I said, all the radiators get heat within 15 minutes of a cold boiler firing up, and after the system was open during the pressuretrol/pipe replacement the valve across the basement pushed out air in the system with enough force that I could hear it hissing)
 
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Old 01-23-14, 10:54 AM
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When you get new pig tail put a tee on it and come off one end with a gauge.
 
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Old 01-23-14, 11:54 AM
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Depending on that control if its an added cutoff or subtracted. Your probably running between .5 and 1.5 psi of steam pressure. But anytime i install a steam system i either use a vaporstat or a replacement pressurtrol and take off those crappy gray ones. Your boiler may be constantly running because it may not be making pressure....if the water in the system is that high, I wouldn't doubt it. You need to find out why the water level is so high.
 
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Old 01-23-14, 12:43 PM
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On a properly sized system the pressuretrol seldom shuts the system down. The t-stat will be satisfied before it reaches that amount of pressure. Your boiler is making pressure just due to the fact your rads are hot. What the system is doing is using the steam as it is being made.

Your boiler may be a little undersized or it just takes a long time to heat your house.
Are you turning the t-stat down to low at night. Is the house insulated.
Once the t-stat is satisfied does the boiler run normal.

Since the t-stat does shut it down and the pressuretrol does work I think what I would do is shut off all the radiator valves to the rads. That way the steam will fill the mains and have no where to go. It should build enough pressure to activate the PT and shut the burner down.

When that happens open up your rad valves, the steam will start moving, the boiler will come on and that should tell you if it's operating as it should.

Why it runs so long is another matter to be discussed.
 
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Old 01-23-14, 12:48 PM
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The water level had most likely been high for a long time before I bought the house. The original pressuretrol was set to the max of 9psi for cutoff. The repair technician speculated the water level was high because the boiler had been overfiring continuously, never reaching 9 psi, but making lots of steam, consequently dropping the water level and causing the auto feed to add more water to the system. When the heat was shut down the steam would condense and return to the boiler, but only after the extra water had already been added, resulting in higher than necessary water level. -- several years of this he said would have caused the water level to be that high. It has not risen since the water level was dropped to 1/2 way in the sight glass about 1 month ago.

Should I try lowering the water level (currently just below 1/2way in the sight glass) even more?
 
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Old 01-23-14, 01:15 PM
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As long as the water level is above the LWCO control you're fine. The lower you can run the water the quicker it will heat but that's not your problem.
The PT should have never been set that high. That's the sign of somebody that doesn't have a clue about steam or they're having a problem keeping the boiler running and don't know why.

You need no more than 2 psi in the boiler. What you have now is fine.
Your boiler comes on @ .5 and if need be will shut off @ 1.5 psi. That's perfect.

As I suggested if you turn off your valves it should shut off on pressure.
Once we're satisfied everything is working we can move on to why it takes so long to heat the house.
 
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Old 01-23-14, 05:37 PM
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I thought you said the boiler never shuts off even when the stat is satisfied. Is this correct? How cold is it down by you now? i highly doubt you're not making pressure because of the weather conditions.

You probably had some bad vents and thats why the old ptrol was set that high. That must have been some tech that set the pressure that high.
 
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Old 01-23-14, 06:31 PM
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RD,
Post number #6 about t-stat.
 
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Old 01-23-14, 06:39 PM
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EV,
After looking @ previous posts something I missed is it seems you're under the impression that the boiler is suppose to shut down @ .5psi. That's the low setting where it comes on. Your boiler will continue to run until it reaches the high limit, which is 1.5psi if the t-stat is still calling.
Just to clarify.
 
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Old 01-23-14, 08:34 PM
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Thanks for that clarification. Today when I got home, I fired up the boiler (house had been empty, heat off all day long). I shut off the 5 upstairs radiators and left the 5 downstairs ones on. After about 20 minutes all the downstairs radiators were hissing at the control valve on the radiator, and there was steam hissing out of the triangle "point" thing that comes out of a pipe on the other side of the basement. 15 minutes later the PT clicked and shut of the boiler! But it only stayed off for about 30 seconds before I heard it "click" and the boiler fired back up. It ran for about 5 more minutes, then the PT shut it off, but this time it stayed off almost a minute. This process continued for a while, but the max time off after 1.5 hours of the t-stat calling for heat was about 2 minutes max. After I opened all the radiators upstairs back up, the boiler kept firing and did not shut off again until the t-stat was satisfied.

I'm thinking that steam pressure is escaping through (1) that triangle pointed vent thing and (2) at all the radiators themselves. This would explain why the boiler doesn't always build up enough pressure to shut off unless some radiators are closed off, correct?
 
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Old 01-23-14, 08:43 PM
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RDSTEAM, The boiler always shuts off after the tstat is satisfied. It's low 30s for highs right now, 11 for the low tonight. We turn the tstat down to about 55 at night! I'm new to steam heat - could you explain what the vents are?
 
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Old 01-23-14, 08:56 PM
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The vents are so you can get steam to the radiators... The steam needs to push the air out of the line. If there were no vents the rad would never get hot...

I think the downstairs one at the end of the line it the main vent so the main line fills quickly to get steam to the rads more evenly..

That vent at the end of the line should close when steam reaches it... The vents on the rads then take over.. They never close...
 
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Old 01-23-14, 09:15 PM
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They never close...
They don't?

I think you've got bad vents if they continue to hiss after steam hits them.

That could be why you don't build any pressure.

We turn the tstat down to about 55 at night!
Wow... that's pretty extreme!

Do you do that because you like it cold?
 
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Old 01-24-14, 07:01 AM
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We definitely like sleeping in the cold!

So hissing at the radiators either (1) after 1/2 of them are shut off causing increased pressure in the system or (2) slight hissing after the system has been firing for 2 or so hours straight is ok?

But the pointy vent downstairs in the basement should not be constantly hissing, should it? I couldn't see if steam was blowing out of it, so I put an old rag on top, and sure enough it made the rag wet and after that I could see steam rising from the wet area. Should I replace it?
 
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Old 01-24-14, 07:16 AM
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I'm not as 'steam savvy' as some... in fact for the most part I only know about steam what I've learned here from the others over the past few years... so I hope one of the steam heads will answer the question about the vents with certainty...

BUT,

I do suspect that the vents should NOT be hissing after steam hits them and a this point I'm inclined to thing that they need replaced...

RDSTEAM is a steam head, perhaps he will confirm this.
 
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Old 01-24-14, 12:06 PM
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Because steam is an open system air always precedes the steam being delivered to the rads.
The mainline vents release the lions share and the radiator vents takes care of the rest.

If the air can't get out the steam will not flow.
On a call for heat as the boiler makes steam you will hear the vents start to hiss. That's the air being released. Once the air is removed and the steam hits the vents they close to keep the steam in until it cools and returns to the boiler as condensate.

If the vents continually hiss and are releasing steam they should be replaced. That's one reason why your not reaching limit and also losing water, not to mention costing you money. It's like heating the outdoors.

You probably have high humidity in the house also from all that steam being released.

The bottom line is the vents will hiss for a few seconds to release the air and then shut down to keep the steam in.
If they DO NOT CLOSE REPLACE THEM. That includes the main vent also.

You should see a big difference in your run time.
 
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Old 01-24-14, 12:46 PM
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Thanks for all of these tips -- I think I should mention that there aren't any of the pointy vents on the radiators themselves -- the steam is leaking from the control valve that controls steam flow through each radiator. Is there an easy way to repair those, or do they need to be replaced completely?
 
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Old 01-24-14, 01:13 PM
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The pointy steam vents are only on the mains.
The valves at the rads have check nuts on them.
You will see a big nut on the valve stem that sometimes comes loose when you turn the valve on or off. Take a wrench or something that fits on the nut and snug it up.
Do not over tighten. Just enough to stop the leak.
 
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Old 01-24-14, 01:27 PM
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As far as the main vents are concerned, these should be vented very fast and if you actually hear them when they first start venting, then they're not big enough or there isn't enough of them. With noisy main vents, comes high velocity steam which can also carry liquid water along for the ride causing banging, hammering, insufficient heat and spitting vents. First things first, replaced those steam vents, not with Home Depot or big box vents...those are GARBAGE. To properly size your main vents i would need to know the length of the runs and the pipe size as well. You are probably going to need a couple of Gorton #1s maybe even a Gorton #2 which is a real big boy and about $60. Do not use maid o mist or some other crap please. You get what you pay for.

As far as the rad valves are concerned, those can either be replaced OR repaired. Usually a quick and CAREFUL tightening of the packing nut does the trick. If not, they can be re-packed which is also a pretty simple task. DO NOT ATTEMPT THIS WHILE THE BOILER IS RUNNING OR HAS PRESSURE!!!!!

If you are in need of some new rad vents i personally like the heat timer vari vents. They're about $25 a piece and adjustable so that you can attempt to balance out the system, which is probably all out of whack.
 
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Old 01-25-14, 11:05 AM
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Ok, so next step is to get working on those vents!

But first, we had a cold snap here and we used the heat a lot yesterday. When I checked the boiler yesterday afternoon, the water level in the sight glass had risen to the top (it was about 3/8 full the night before when I shut it down for the night). So for some reason the water level rose dramatically over the course of 8 hours or so, even though it hadn't risen in the month since I had the water level drained (but in that month the boiler had not been used more than a couple of hours each day as we just used the radiators to heat up the house in the morning and then used the heat pump to maintain temp throughout the day). What would have caused such a sudden jump in water level? I checked this morning before firing the boiler back up and the water level was still high.
 
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Old 01-25-14, 12:06 PM
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Zone 2 is reading 0v in both cases.
A few things...

Leaky automatic water feeder

SLOW RETURNS. When the steam goes into the system it begins to condense. If the condensate takes it's sweet-azz time coming BACK to the boiler, the water feeder will sense that it needs to feed some water, and when it does, and the boiler stops firing, and the condensate slowly makes it's way back to the boiler, it now has too much water in it.
 
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Old 01-25-14, 07:57 PM
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I think trooper hit it right on the head with the slow returns. Some water feeders have adjustable delays that can be set for this reason. If yours doesn't you might want to disconnect it and do manual until you get your vent situation fixed.
You are using a lot of water through wasted steam. Between the steam vents and possible surging and slow returns you might want to feed manually until fixed or see if you can adjust the delay time.
 
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Old 01-26-14, 12:05 PM
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I came up with an idea to temporarily solve the problem - I am leaving the LWCO connected but I am closing the water valve at the water feeder - the LWCO will still engage and will shut down the boiler in the event of low water, but the water feeder won't be able to add any extra water. When enough condensate returns to the boiler the LWCO should disengage and allow the boiler to fire back up. I'll see how this goes for a couple of days, although we are hardly using the boiler right now (temps in the 40s and 50s tomorrow) so the heat pump is doing the work!
 
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Old 01-26-14, 12:21 PM
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ev,
Never disconnect the LWCO. That's just looking for trouble

Good Luck,
 
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Old 01-26-14, 07:05 PM
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I think he means that he's just killing the water feed section of it and leaving it as a safety to shut the boiler down. He wants to allow the condensate time to travel back and start the boiler back up instead feeding and overfilling. These low mass stream trimmed hot water boilers are what's really killing the lost art.

You would probably need a condensate tank of sorts to help with you slow returns. They can be built with piping but need to be properly sized and installed. I wouldn't worry too much considering it probably doesn't get that cold often down by you.
 
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Old 12-08-14, 05:20 AM
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Having same issue

Work on heating systems at work but have never worked on steam heat.

I've replaced the pressuretroll every vent on every radiator and have repacked all control valve with graphite. Boiler heats house fairly quickly but after running for about 45 minutes,steam will start pushing through the radiator vents loudly.replaced gauge on boiler but it does not move at all.this week I will be adding a second gauge to the pressuretroll.

Any ideas thanks
 
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Old 12-08-14, 01:48 PM
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Kjfri189.....Is your ptrol set to cut out at about 1.5 or no more than 2 psi's?
 
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Old 12-08-14, 02:02 PM
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Did you check that the siphon tube (aka 'pigtail') was not clogged? This is a very common cause of high pressure in steam boilers.
 
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Old 12-08-14, 06:13 PM
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Yea blew out the pigtail not much for a blockage.

Cut in .5 diff 2 so cut out currently is set to 2.5.

Have never seen it shut off from the pressturetroll only shuts off when Tstat reaches set temp.

Can't even sleep its likes an alarm clock every morning : /
 
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Old 12-09-14, 08:47 AM
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OK, well, you need a functioning pressure gauge and you say you are going to take care of that.

If the PT is not cutting the boiler off at the right pressure, it's either a blocked pigtail which you say you are sure is clear OR a WIRING ERROR...
 
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Old 12-09-14, 10:54 AM
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If I manually trip the pressure control it shuts the boiler off though so I think the wiring is correct. Going to put another gauge tonight to see.

Thanks for the help I appreciate it
 
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Old 12-09-14, 04:44 PM
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Yeah, if you can shut it off by manually moving the control it would seem to be wired properly.

So that leads back to clogged pigtail then... you say you blew it out though. Did you remove the pigtail when you did so? You are ABSOLUTELY certain that it's not blocked?
 
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Old 01-10-15, 04:06 AM
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Still not working properly ugh. Every air vent in the house started hissing this morning,

Bought a new pig tail last night going just to change that out.
 
 

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