Help - Boiler Pressure Release Question

Marc_3

Hi,



My boiler ran this morning for quite a while - maybe 1 hr from cold start (not used in 24+ hours). I was trying to heat the house up so I could shut down our generator for the day.



I hadn't noticed that the temp had not been satisfied, and suddenly heard a "chuffing" sound, and realized that it might be the boiler release valve, so I shut the "kill oil" switch and waited a minute. As I suspected, my basement was a bit steamy and my boiler pressure release valve had functioned and sent steam / water to the floor.



My question - we are post-Sandy and I can't get a hold of our steam guy (or anyone else). What do I need to look at to understand whether the boiler is safe, etc. I'm guessing my pressuretrol cut-off isn't operating correctly.



My water level was a bit on the high side before we started, so maybe that's why it steamed over. But it still should have shut down on high pressure. When I went down, the standard gauge read 5 psi, but that was after release. I'm assuming I need a new or cleaned pressuretrol.



Questions:

1) What should I look for? Nothing looks damaged.

2) After cooling, I'll check my water level.

3) Can I safely run for heat until I can get my heating guy in? I'll pay a bit more attention and shut down the heat before the pressure gets high, but we need heat with the temp dropping. We are on generator, so the heat only runs when I tell it to and the generator is on.



Boiler is a Weil McClain Gold circa 2005.



Thanks so much in advance.

Rod

Safety Issue

Hi- Sorry to hear you are suffering from Sandy.  You're on the right track in thinking your Pressuretrol should have stopped the boiler from building so much pressure. You DON'T want to operate the boiler until you determine why it didn't cut off!!

    Since you're running off a generator, is it possible that you wired it up incorrectly so that somehow the safety circuit (pressuretrol ,LWCO) was bypassed? 

- Rod

bob_46

Pressure

Check the pigtail on the pressuretrol and make sure it isn't plugged.

Marc_3

Thanks

No, all the circuitry for the LWCO, Auto-Feed, and Pressuretrol were connected and energized at the time of failure.



I have a hydronics specialist coming tomorrow to look at it. He concurred with the opinion here - don't run the heat.



Thanks for the advice and quick help.

Marc_3

Clogged Pigtail

It was a clogged pigtail. Thanks everyone!

crash2009

There is a fairly inexpensive modification

 that you can do yourself, and will help to troubleshoot this same problem in the future. 

This is what most of us have done.  Add a T between the pigtail and the pressuretrol, and a 0-3 psi gauge.  Before you turn on the boiler for the first run of the season, remove the gauge and blow in the hole.  If you can't blow, the pigtail is plugged.  The gauge also comes in handy for other diagnostics, such as setting the pressure on the pressuretrol.



Here is a rough sketch of how to put one together.  I can't seem to find a good photo right now.

Marc_3

0-3 Gauge

Since the pigtail is now clear, my system is properly shutting off on pressure. My pressuretrol is an additive Honeywell type and is set down most / all of the way on the cut-in. The differential is set at 1.5-2 right now since it seems to be short-cycling a bit at 1. (Not sure if it is truly short cycling as this is an exceptional siutation - coming back from a long setback and trying to raise the temperature a lot since the power is out. I ran for 25 minutes, and then it cycles off for 2-3 minutes and then on for 1-2 minutes...)



I don't want to mess with it too much right now (with the lack of power) but I intend to:

1) Check to make sure cut-in is all the way down at 0,5

2) Check try and get the differential as close to 1 as possible but avoiding short-cycling.

3) Check my main vents (1 x Hoffman 75 on each of 2 equal length mains) for function and size appropriateness.

4) Get a 0-3 gauge to replace my 0-30.



I'll post a picture, but what is the best source for the 0-3 gauge? I can't find the thread about it. Can I put in on the same pigtail as my pressuretrol and 0-30, or do I replace the 0-30?



Thanks.

crash2009

I have been using

 the Wika 0-3 psi for several years now.  There have been some complaints from others re their inability to handle vacuum.  Not sure if they are still recomended, but mine is still working.  You have to keep the 0-30 for code/insurance reasons.  2 gauges and 1 pressuretrol can be run off 1 pigtail. 



 http://www.gaugestore.com/prodinfo.asp?number=33020





This might not be the best setup, but it is how I have run mine for a couple seasons.

Boiler Talk

0-5 PSI Gauge Dwyer

I installed a 5 PSI gauge and a shutoff valve just below a pressuretrol.  I doubled the venting on the mains by using 2 Gorton #1 vents.   I don't have a vapor-stat just a pressuretrol.  I only once saw the gauge move to 8 ounces and saw it cutout at 1.5 PSI or the setting of the pressuretrol.  Usually it the gauge shows nothing in the beginning and when running.  I also have some short cycling. 



The gauge has an Accuracy: 1% full scale. ANSI B40.1 Grade 1A.





I don't know if this gauge isn't handy, but the short cycling is bothersome.  Someone wrote we need to control pressure at lower settings and it is only possible with a vapor-stat.  True? 

BobC

Why the cycling?

So now the question is why is your boiler cycling on and off?



Is your thermostat setup to control steam? It should be set to one cycle per hour or perhaps 2 in some instances. A lot of the newer thermostats come set to hot air which is 5 cycles per hour and you have to set them for whatever type of heating system you have.



You said you only saw your pressure gauge go up to the high limit once, if that 5 PSI gauge and the pressuretrol are on the same pigtail check your pigtail to be sure it hasn't plugged up.



Pressuretrols only go down to 1.5 to 2 PSI, you need a vaporstat to get lower cutout pressure.



Bob

Boiler Talk

Cycling

Around 6 PM today the thermostat called for heat.  The boiler fired for about 8 minutes, then ran I guess about 15 minutes and stopped, started one last time and stopped when the thermostat clicked off.  The thermostat is set to go from 64 degrees to 69 degrees at that time.  I set the thermostat to 1 cycle per hour per the instructions for steam. 



I probably asked this question before, sorry if this a repeat, what causes this?  Is this normal?  My boiler is probably too big.  What can you do if you learn after it is installed that it's too big? 

Enreynolds

Steamers

Tend to not like setbacks.  Try reducing your setback and see if that helps your short cycling.  Depending on your boiler style, you may be spending more because of the short cycling than you are saving with the setback.

Eric

BobC

To big?

If the boiler is to big it will cycle on pressure because it builds steam faster than the radiators can condense it. It has not been really cold out yet, does the boiler short cycle in the depths of winter?



How many sq ft of steam is the boiler rated for (should be on the name plate) and how many sq ft of radiators do you have in the house? If the boiler has a lot more capacity than you need there isn't a lot you can do but tighten up the house so you don't needlessly lose heat.



Running at lower pressure helps but it won't correct for to large a boiler so I'm not sure a vaporstat would do you a lot of good. I agree that a smaller setback might help things, I bring my system up in steps so it never see's more than a 3 degree increase.



Bob

Boiler Talk

Course of Action.

I have a Peerless WBV-03 that has a range of SF radiation from 321 to 385 using either a .85 gph or 1.05 gph nozzle.  The radiators in my home total 175 SF.  It use to be 208, but one radiator is in storage.  There is a second radiator in the basement that I don't know was ever used.  I suppose it was since the number of rooms in my house has decreased.  There are plugs on the mains that suggest there could have been other risers.  There is about 150 feet of pipe.  Today, the oil service tech put a .75 gph nozzle and made the adjustments for air intake on the burner.  He did all of the tests for CO2 and efficiency (83%).  When asked about short cycling he said the LWCO system will stop the boiler to test the level.  I never heard this before.  I'll have to see how this works.



So with a smaller nozzle, can the SF radiation output be calculated roughly?  

BobC

A bit more then 10% less

My rough calculation is that firing at .75GPH vs .85 will result in 283 sq ft of steam being produced. If you go down further I suspect your efficiency will suffer. I don't think you will get good results f you tried to go down near the amount of radiation you have now, but I'm by no means an expert.



Bob

Hap_Hazzard

LWCO

If you have a CycleGard LWCO, it will turn off the burners for 90 seconds every ten minutes. You can tell when this is happening by the tree light on the top of the unit.

Boiler Talk

Good Enough

I don't know the results yet as it isn't cold in NJ.  I probably won't see much difference. Is this worth it?  I am pretty sure I have the LWCO device mentioned above.  Maybe nothing was wrong with the cycling.