Installing a vaporstat - but which one??

elfie

the pressuretrol is not a good way to manage a low pressure system - it needs to go



the pressure flexibility needs to be 0-2.0 psi (hoping to keep it closer to 6 - 9 oz.)



which vaporstat would be best? what control ranges are available? and are they reliable?



and the gauge also needs to change too



a side question is what impact will the lower pressures have on the burner motor (ie. lower pressure I guess will mean lots more cycling)



thanks

Luv'nsteam

How many do you have

To choose from?  When I bought mine, the only manufacture I found was Honeywell.  After reading several posts on here about it, it leaves something to be desired but seems to be workable.  Mine has not been used yet, so only time will tell if it works or needs to be calibrated or something.



Thanks,

Mike

Paul Fredricks_3

well

I don't think there is one that will do low ounces and pounds. You may need to install 2 if you need that flexibility. The L408J1009 will do 0 to 16 oz, and the L408J1017 will do 0 to 4 lbs. I don't know how accurate the second one would be for the ounces of pressure you want.



Why do you need the flexibility? 

Jamie Hall

Unless you are pretty sure

that your system will definetlly work at one pressure range or the other, I'd go with the 0 to 4, as the 0 to 16 ounce simply won't work if you need higher pressure for some reason.  On the other hand, if you are reasonably sure that you won't have to go over 16 ounces to have your system work well, go for the 0 to 16 ounce, as it is more accurate at the very low pressures.



On the side question -- assuming that your system is properly vented and all, there should be very little difference in the cycling, except that the on half of the cycle should be shorter.  Which is good -- the rest of the on half is spent simply squeezing dollar bills into the pipe...

elfie

its almost comical - gauge installation

the PSI gauge on this low pressure system goes as high as 30 - how clueless the pro was who installed a pressure trol and this gauge



i found this gauge 0-5 psi, which appears to be appropriate (is there a better gauge that show be used for low pressure system?)



still thinking about the 0-5 psi range on the vaporstat - seems it has enough room at low end to hit 5 ounces  - question is reliability;



i would prefer the 0-16 ounce version - i brought down system to 1 ounce on pressuretrol and no problems, and will try taking it lower to see if its ok.



http://www.weissinstruments.com/low-pressure-diaphragm-gauges.html

Luv'nsteam

A word of caution about

Removing the 0-30 psi gauge and P-trol - as mentioned in another thread, there may be codes/regulations/etc locally, state and maybe federal about the necessities of the 0-30 psi gauge and P-trol.  Find out before you remove them (if that's your intention).  As for them being there, my brand new Peerless WBV-03 steam boiler came with a P-trol and 0-30 psi gauge from the factory.  I added, via a tee and second pigtail, a 0-16 oz gauge and vapor-stat.  While I am unaware of any regulations controlling my use of the original equipment, I see them as additional safety equipment and therefore wired the P-trol in series with the vapor-stat.  If for any reason the vapor-stat would fail, the pressuretrol will keep the boiler in check.  Like Dan states: "...belt and suspenders".  Safety first.  Always. 



The second reason I left the P-trol in place is for blow downs of the boiler and mud leg.  It's hard to reach pounds per square inch for cleaning purposes if you cannot go over 16 oz of pressure.  I installed a ball valve to isolate the V-stat & 0-16 oz gauge during blowdown.



Thank you,

Mike

elfie

vaporstat changeover - a great response

not sure i am concerned about the regs



but i really like the idea about leaving the pressuretrol and original pressure gauge in place as a secondary cutoff control;  and way to get a quality blowdown.



would be very interested to see a pic of how you isolated the pressuretrol and the vaporstat



you added support for a purchase decision to get a 0-5psi vapor stat (i suspect it may not be a problem to achieve approx 6 0z of pressure with this vapor stat ???)



thanks for a really helpful response

Abracadabra

wut!

"not sure i am concerned about the regs"

crash2009

Nice

picture. 

elfie

regs??

its a low pressure system



what regs are out there that address the type of pressure control device you can have in place for smaller and lower pressure boilers



anyone know specifics on reg requirements for the pressure control devices??

ChrisJ

Just a homeowner but,

It is required to have a gauge that goes twice as high as the boilers pressure release (15PSI).  This is why the 30PSI gauge is there.



Codes are in place for good reasons,  I recommend following them.  If you do not know the local codes in your area they can usually be found at the local library.

elfie

no doubt we can get the reg issue clarified

there is much discussion about installing vapor stats (i like the idea about a secondary pressuretrol), i hope there is an expert out there who can cite the regs out there to address this.



good stuff to know

Mark N

Pressure

Elfie,



I have a boiler that always runs at less that 2oz. of pressure and I have a pressuretrol not a vaporstat. The reason the pressure is low is because the boiler is properly sized, the pipes are the right size, and I have adequate venting. If I were to install a vaporstat it wouldn't save me a penny as I never cycle on pressure.

elfie

2 ounces? ASME regs

running a boiler on 2 ounces is amazing and further its being done on a pressuretrol?  so its possible to set it this low without any problems?





i took a look at the NJ boiler regs

12:90-4.5 Low pressure boilers



and it said

'(a) Low pressure boilers shall comply with Section IV, Heating Boilers of the ASME Code'.



i then tried to find ASME code guidance and basically its a book that has to be purchased



very troubling this type of info is not freely available

Luv'nsteam

Here's the pic of

My P-trol & gauge and V-stat & gauge,  Wiring N/A because my install is not complete.  I have been treating this as more of on obsessive hobby then a necessity, which I can do because we have a wood stove.  Hope it helps, elfie.



Mark, what you say makes sense and if true, since I followed all of the rules as provided by Dan in TLAOSH with questions answered by posters at Heatinghelp.com to properly size my new boiler, then I waisted money on my vaporstat, gauge, etc,  But I have seen many installs like mine posted here and the virtues of such an install discussed here, also.  So I suppose I will have to wait and see.  It still looks cool with both controls, even though that is not a good reason to add one, but I digress. 



BTW, I am a homeowner with a strong technical background who was put way off by the incompetent knuckleheads (three of them from three different companies) that came to my home to provide an estimate to replace my original boiler.  But I am also fortunate that my brother-in-law and a very good friend are both top-shelf HVAC guys, even though neither is strong in steam.  But both have provided help here and there with my 'hobby' project.  I do love steam.... 



Thank you,

Mike

elfie

thanks - heavy duty piping

thanks, nice looking controls



thats some heavy duty piping going on

Luv'nsteam

Heavy duty pipe

When I am finally done....... I will post several pics and explanations of the what's and whys. 



Thanks,

Mike

Mark N

Cut-Out

Elfie,



My pressuretrol is set to cut-out at 1psi and cut-in at .5psi and it does this when I force the pressure high to test the pressuretrol. You might be misunderstanding what a pressuretrol does. It is only a switch that is activated by pressure. It does not actually determine what pressure your boiler runs at. The operating pressure of the boiler is determined by the size of the boiler, the size of the piping, the amount of radiation, and the venting. If the boiler is grossly oversized the pressure will be high because the boiler produces more steam than the rads can condense. If there is inadequate venting the pressure will be high because the air can't get out and the steam compresses it. In a steam system with a properly sized boiler, piping, and adequate venting the only time you should cut-out on pressure is after all vents have closed because the rads are full of steam.

Rod

Who needs a 0-30 PSI Gauge!

I apologize if I sound rude but I think we really need a reality check here.

Dismissing regs and rules isn’t really too swift and you’re right they really don’t matter. What does matter is that if several safety devices (required by regulation ) FAIL,  the thing in your basement now know as a boiler changes its name and becomes known as a BOMB!



If you don’t think that there is always the potential for this I would suggest use the Site Search function and look up “boiler explosions”.



The 0-30 PSI Gauge has an important function. It reads twice the pressure of the safety valve.

Let me run this scenario by you. You’ve removed the 0-30 PSI gauge as this is a “low pressure steam system” so you don’t really think you need it as a 0-3 PSI will serve to monitor the operating pressure far better.

    One night you note that your radiator vents seem to be hissing far more than normal. You go down and check the pressure gauge and the 0-3PSI gauge is pegged to the maximum but since the safety valve hasn’t gone off, you think, “There must be just a bit of dirt in the vaporstat so the pressure probably just a bit high, probably around 4 PSI.” “It’s probably no big deal, I’ll take a look at it tomorrow or call someone!”  Think about that safety valve and what happens if it hasn’t gone off  because it is non functional.  (Hint- Boooom!)

   Let’s go back to the beginning of the scenario and add a operational  0-30 PSI gauge. You hear the hissing, you enter the basement and note the safety valve hasn’t gone off, You check the 0-3PSI gauge. It’s pegged !  You then check the 0-30 PSI gauge and it reads 25 PSI and climbing. You think, “Oh my G– , the *&%#$#*!!** safety valve is bust!” as you dive for the burner cut off switch!   (Hint- No Boooom!)

The 0-3 PSI gauge function is to read low pressure. The 0-30 PSI gauge function is to read high pressure . You need both!

- Rod

elfie

and the correct answer is - you need both

and the installers should be more helpful to ensure proper operation



putting a 0-30 psi guage is important to keep but opens the door to a poorly operated boiler (ie. too much pressure). the car you drive doesnt have a speedometer that goes up to 2000 MPH (not an exact analogy but it makes the point)



the purpose of the discussion forum is to flesh out issues and make rationale decisions and learn that certain pro talent out these needs scrutinization because the hvac world has become too complex and with complexity comes problems. 



i dare say that most people with low pressure steam boilers are operating them at too high of a pressure.  and they dont know how to change the pressure because the pressuretrol device is not a user friendly device and unless you research how to use it, its not that easy to understand. and the service providers dont make an effort to ensure your system is operating at an appropriate pressure level.



Blind faith in a service provider can lead to a really bad outcome.

mcsteamy

Good Advice

Rod,



That's good advice you give.  I was checking out the boiler yesterday in a house I am looking at, and encountered just that scenario.  The house has only been vacant for about a month, so I wasn't too concerned that there were any problems.  A few days ago I filled up the boiler, watched it for awhile, and all seemed well.  I set it to 45 degrees to thaw the house and let the boiler cruise along.  I came back today and cranked it up to 50, and returned about an hour later.  A few of the radiator valves were hissing steam like crazy -- they all looked old, and probably not replaced in ages.  I then went downstairs.  25 PSI on the pressure gauge--safety valve didn't blow.  I jumped up, shut off the boiler, and went outside.  20 minutes later, the radiators were not hissing steam, and weren't even hot, but the gauge was still at 15 psi.  There was no pressure left in the system.  I fired the boiler again, and in no time the gauge was back at 20 psi.  The gauge was broken.  It sure scared the heck out of me though. 



Fortunately, this wasn't a disaster, but had the safety equipment failed, and the gauge been replaced with a 5 pound gauge, there would have been no way of knowing how bad the situation was.  That 30 pound gauge might seem like a waste.  It isn't.

Dave in QCA

More Complicated

Elfie, in a previous post, it was determined that you also have a proportional pressuretrol, in addition to the normal pressuretrol, and that it is there to operate a modulating burner.  Am I remembering that correctly?



So, when attempting to answer the question in this thread, it becomes a completely different matter when the entire picture of your system is considered.



Boilerpro has had some experience in setting up modulating burners on vapor pressure systems.  As I recall, he fabricated and combined compenents successfully.  Honeywell does not make such a device.



If you install a vaporstat, which you could, it is going to change the operation of your boiler to On/Off instead of modulating, and the purge cycle that will occur with that burner is going to waste a lot of heat if you wind up with a short cycling situation.

Dave in QCA

Regarding Regs......

What kind of building is this?  What is it's use?  Places of public assembly usually have stricter regulations sometimes including boiler inspections and licensing.  These codes vary by state.  They are usually more strict in a place of public assembly because of the increased number of lives that may be harmed or lost by an improperly maintained or unsafely operated boiler. 



Code books such as ASME, NEC, or Nfpa LSC are produced at considerable cost.  They are generally used by engineers, inspectors, and qualified installation contractors.  It would be convenient if these publications were available at no cost, but it is no surprise that they are not.  You might be able to find the code book you are looking for on the shelves of the library at the nearest university that has a college of engineering.

elfie

purging can be very wasteful

yes i believe one pressuretrol adjusts the burner, not sure how much modulating its doing as the boiler tends to fire at same rate all the time; the boiler is not used all the time and therefore when turned on the fire rate is at a high level (ie. not much warm up) - i think there may be stress issues that maybe a Low fire hold device would make sense - do you think a low fire hold device is a good idea.



i guess boilers are more of a on/off situation ( i suspect most boilers operate this way)





the pressure gauge shows a lot of pressure lost during purge process before burner kicks on - would the adjusting cutin setting to zero PSI, so that there is not any pressure in system when purging starts, be good and help efficiency?



one steam boiler we have is a large commercial 12 section HB smith boiler that is very oversized.

Dave in QCA

answers...

The burner should be sized so that the hi fire rate is the exactly what the boiler is designed to be fired at.  Modulation allows a lower firing rate to avoid the on/off cycles and the waste that some with purch, not to mention rising and falling steam pressures that may interfere with the distribution steam.  But, the burner firing on hi fire should not be causing any particular stress to the boiler.  Is there some reason that you think it is?



You may already have a lo fire hold,  Can you take a picture, or several, of your burner and its controls.



Having a 0 steam pressure will not effect the heat that the purge cycle will blow up the chimney.  It still wastes heat because it cools the boiler water down, (a little)



How oversized is the boiler?  How have you determined that?  Have you done a radiator survey to determine your EDR?  If not, that would be a good thing to do.

elfie

burner controls

pics of burner and controls



i am concerned that when boiler is started when cast iron is a room temperature it should be warmed up slowly to avoid thermal stress. 



maybe we can adjust settings to reduce burn rate to stabilize the pressure as it tends to be a rollercoaster on the pressure gauge when its used.



but a high fire rate is nice as i believe this tends to heat up space faster (space is a large space for 1100 people with high ceilings) and steam boiler supports a couple blower units with lots of wall vents.

crash2009

Now I get it

This is not a residential system.  You guys turn on the heat, have an 1100 person function, then turn it off.  Essentially you are recovering from a setback every time you start it.  No wonder all hell breaks loose every time you turn it on.



Most of the systems I read about around here are residential.  A lot of people who prefer the house to cool off a bit at night, program the thermostat to reduce the run time of the boiler for nightime, then program the thermostat to warm up the house before they get out of bed in the morning.  This 4 or 5 degree setback upsets the rhythm of steaming and condensing, and the result is high pressures and the feeling that something is going to blow up.



Some have had success with a multi stage recovery in the morning.  Perhaps this might work for your building.  Don't know if you have a programmable thermostat.  One thing you could try is rather than increasing the temperature of the building from (I'm guessing 50F to 60F) all in one step,  Break it up into 3 or 4 steps.  Just a thought, I could be way off. 

Dave in QCA

controls

Elfie,  Have you operated this boiler and/or changed the controls on the burner to check what the effect is?   



The following is a description of how this type of burner is set up.  This assumes that this burner was set up in the conventional way and that no one else has been tinkering or modifying the wiring.



On the main burner panel, there is a toggle switch that says on / off.  This obviously would shut the burner off.  On, would allow it to operate.  There is another toggle switch located directly beneath that one, and it is labled Manual/Auto.  There is also a dial that says Manual Pot.  meaning Manual Potentiometer.  If the manual/auto switch is set to auto, the modulation of the burner will be controlled by the modulating pressuretrol, and according to the pressures it is set at.  If you turn the switch to manual, than the firing rate of the burner would be controled by turning the Manual Pot. dial.



There is also an added switch to the left of the burner controls.  It is labeled Auto - Off - Hand.  I do not know what the purpose that switch is.  It could be a number of things.  One way to find out is to change it from Hand or Off and see what function is controlled.  It could be assumed that in the Auto position, there is some other device that controls the function fo whatever is being controlled.

Dave in QCA

air handling units?

If you have other systems that are heated by steam, that are in addition to the vapor pressure radiator systems that also exist in this building or buildings, it may be quite possible, and in fact likely, that this system will not operate on vapor pressures.

elfie

modulating pressuretrol device

thanks for the info



could i get some info on how the modulating pressure trol is supposed to work?



ie. as pressure builds up, how should burner modulation change.



it seems this boiler always operates at the same fire rate (when auto is selected); by selecting manual it does allow manual control of the burner



thanks