How can I best lower my operating pressure?

jalubarsky

Since my original post I implemented multiple suggestions with clearly improved results.
I will post a pic of one of my new main Gorton No 2 vents. I added them to each of my three mains. This pic is where I had no main vent because a new radiator riser was added where the original vent was located. My smart friend suggested that instead of messing with the 2 inch iron main (70 years old) we add it as close as possible on the copper riser. We did this and the vent cranks out air upon start up and has reduced the heat up time for this main as well as the other two mains well under half.
The other thing I did was add the 0 - 3 psi gauge so I could accurately figure out what was going on. It turns out the system is working properly but after many attempts to calibrate my Pressuretrol so it would turn off near my shut off pressure (under 2 psi) I have not been able to do so.
- My controller is a mercury switch which can only be adjusted by turning the central post. If I screw it counter clockwise so the unit turns off at say 2 psi my switch gets stuck open. To be sure it does not get stuck I have to make it so my system shuts off at around 2.7 psi.
- Other than buying a more precise Pressuretrol are there any suggestions?

KC_Jones

Maybe it's just the angle of the picture, but did you verify your pressurtrol is sitting level? Since this is the older mercury style control it needs to be level or it won't work correctly. Yours appears to be out of level judging by the top of the boiler. Other than that the only way to truly lower pressure is with venting. I just read back through your other post, how many vents did you add to the main? I see 2 in that picture, did you add the recommended amount? Just curious what you ended up doing. If you are truly concerned with the pressure then venting is the only thing that can keep it down. The pressuretrol simply shuts the system down until the pressure drops off then restarts the burner after that. The pressure is because the air can't escape fast enough. To restate the recommendation is 1 Gorton #2 vent for every 20' of 2" pipe and if you have a 50' main I would round up and go with 3.

Jamie Hall

I second KC's comment. Either the pressuretrol is out of level or the boiler is. The mercury pressuretrols are accurate and reliable -- but only if they are exactly level. The behaviour you describe is exactly what I would expect from a pressuretrol off level in the direction it looks like...

jalubarsky

Thanks for this feedback. To answer I did notice the controller was slightly angled to the left. I straightened it so we will see if there is a difference. As for the vents I started by adding 1 Groton No 2 for each of my 3 mains. This added a lot from what I had. I clearly reduced my start up times.
A question. I have read that the Varivalve vent has similar capacity to the Gorton No 2. If true they are a third of the cost. I want to add more but am trying to take a step at a time. Thanks.

nicholas bonham-carter

Gorton #2's are still the big dog in the world of venting, being several times larger than the varivalve, as far as I can see from the venting chart for sale in the store here. A sizeable investment, but so is the total amount of fuel used during the winter.--NBC

jalubarsky

I am sure I do need more main vents and will most likely bite the bullet and add more. Good news is the time for all of my radiators to get hot has come down a good amount. I would guess it is around 20 - 25 minutes versus an hour. I am now trying to balance my radiators and actually found that one of my older vari-valves was not closing all the way. I had the bedroom door closed and it felt like a mini steam bath. I ended up replacing 4 radiator vents with Vari-valves from Fairfield NJ and have noticed those rooms heating up far better and in balance with the rest of my house. My biggest issue now is my Pressurtrol climbs to 2.5 psi then kicks off even though my setting is at about 1.5. If I try to lower it the mercury switch sticks open. Instead of relying on the little arrow within the controller I used my level and made sure it is perfect so I am not sure if I should tinker with it any further. All suggestions are welcome.

Fred

So you leveled the Pressuretrol. It also looks like the Pigtail may be a little off. Make sure the Pigtail is at 90 degrees relative to the Pressuretrol. It looks like it may be off a bit. That pigtail will flex as it gets hot and the idea (with mercury switches) is that it can flex front to back but should not have any side to side movement at all. In reality, a Pressuretrol and/or a Vaporstat is more a safety device than a control device. Except for those occassional days when the outside temps are extremely cold or when the boiler is trying to recover from a deep set-back, you should not ever reach the upper limit of the Pressuretrol. You say you know you need more Main vents. Put them on. That will likely take you to the next level and reduce your steam pressure.
Did you say your Near boiler piping is correct? Is the boiler fairly well matched to your total radiator EDR? Those are other factors that will affect pressures.

Jamie Hall

You may have better luck with the little arrow... Another approach, which is a bit of a kludge, but works, is to set both the main scale and differential to the same value, and then run the boiler just until it cuts out. Now as it cools, the bulb should tip back. It probably won't. So gently -- very gently -- tip the 'stat clockwise until the bulb just flips back and tighten it there.

jalubarsky

Well not sure how much further info is interesting to folks but as I read further into Dan's - We Got Steam - I am understanding more and more why my system takes a while to start up from a cold start. As previously stated I have 3 mains, 50, 60 and roughly 70 feet long (2 inch piping). I figured out that I have 5 radiators on the 50 footer, 4 on the 60 (2 of the upstairs rads) and 8 on the longest 70 footer. So I clocked how long does it take to get the main vents hot and closed - the 50' takes 9 mins with one Gorton #2. The 60' with one Gorton #2 14 mins and my longest most burdened main 25 mins with two Gorton #2's. If you remember this main used to have no vent and used to take well over an hour to heat up so I am making good progress (and hopefully my gas bills will show it). This has made a big difference in start up and overall balance but still have a way to go. So I will continue to improve my weakest links until I can get better performance. Current issues -
- need to add more venting to longest leg to try and get the mains to heat up at the same time.
- Most of my mains are well insulated but most of my pipe connections are not insulated so I will do that also.
- when my mains and all 15 radiators are hot my system does build pressure up to about 2.5 psi when my pressurtrol shuts it off even though my setting for shut off is under 2. My pressure used to drop pretty fast back down to 0 but now it takes maybe 2 minutes to slowly drift back to 0. I did replace 5 radiator vents which were either slow or not closing completely. I continue to try to lower my cut off by turning the center screw counter clockwise but when I do this the controller can get stuck open hence no heat which is unacceptable. So for now I am keeping it at this 2.5 psi shut off mark because overall my system is working way better than ever before with all radiators and rooms getting nice and warm.
- My last point is I am confused from the book if there is a way for me to not have my boiler build pressure so fast when my entire system is hot? I would not say my system is short cycling but it does crank up then kick off because of the 2.5 mark which doesn't seem right to me. I think my boiler may be a bit oversized (Burnham IN6PV) but not sure. My house is roughly 2,600 sq feet in a very economical cape configuration, 15 radiators.
So as always I welcome any suggestions or insights about my ongoing project. I find this fascinating and a neat challenge.

Mark N

If all the rads are hot, why is the thermostat still calling for heat? Does this happen when maintaining the temp or recovering from a set back?

jalubarsky

Thanks again for these inputs.
This is when recovering from the night where we lower the set point. So far this winter in NJ it has not been very cold so once the house gets up to temp in the morning the system does not have to work very hard to maintain 67 degrees our set point. My pressure as it makes all rads hot is between 1 and 1.5 psi. I have tried to set my Pressuretrol to kick off earlier but when I do it gets stuck open so I turn my central post back clockwise to make sure it closes after the pressure drop. I have leveled my pigtail, my controller and I can't seem to get it to kick off earlier without getting stuck
About a diagram I have put on paper my system by floor to scale on graph paper with the main vents, rad locations, and riser locations. I know I need to add some more main vents and will do so.

Jamie Hall

there are two flavours of pressuretrol: addi\itive differential and subtractive. The additive takes the main scale setting and adds the differential setting. Thus the main scale setting is the cutin pressure, and the cutout is the main scale plus the differential. The subtractive is the opposite: the main scale is the cutout, and the cutin is the main scale minus the differential. Take a look and see which you have (it will say) and see if you can set it to get a cutin around .5 psi and a cutout around 1.5.

jalubarsky

Sorry for the delayed response. I have a 404A Honeywell subtractive Pressuretrol unit. My problem is trying to get my unit calibrated so it cuts off where it is set. I have my main set at slightly less that 2 say 1.75 on my main and I have the differential set at around 1. My operation is way better with radiator tuning and the adding of 2 Gorton #2's on my slowest- longest main and one Gorton #2 on my other shorter mains. This has reduced my start up times significantly which is great. I also replaced 6 radiator vents for one that leaked steam when it was hot and a few slower performing ones. So all in all things are way better but I still cannot adjust the pressuretrol stem so it kicks off at the main setting of 1.75. If I turn my stem counterclockwise further the mercury switch will get stuck open and hence no heat. Now that we are having very cold evenings (tonight 4 degrees) I don't want to risk this. At this time with my calibration and settings when the system is cranking and all is hot I will build pressure to 2.9 psi then it cuts off. So I am not sure if I should leave well enough alone, replace my pressuretrol with a Vaporstat unit or further try with my current unit.
Thanks again.

Jamie Hall

Have you checked -- very carefully -- the levelling of that pressuretrol? The mercury variety (keep it! much more reliable than the newer ones) is very sensitive to being out of level. Even a little bit. There is or should be a little pendulum arrow visible inside to help level it. Since you seem to have a decent pressure gauge, though, you can also keep an eye on things and very very carefully twist the whole pigtail anti-clockwise (in your case) so that the mercury switch just flops over at the pressure you want.

jalubarsky

I did try to make the unit perfectly level by using a level and also looking at the arrow in the controller. I believe it is correct but one never knows. I will triple check it. Relative to your pigtail comment I am not sure I understand. I did put in a new pigtail when I added a 0 - 3 psi gauge. My pigtail is positioned front to back as suggested. Are you saying I should rotate the pigtail counterclockwise and effectively rotate my pressuretrol with it?

Fred

If you can't get the mercury switch to trip at the pressure you want, @Jamie is saying that by tilting the pigtail very slightly , counter clockwise will put the pressuretrol (and hence the merury switch) off center enough to get the switch to trip earlier than it currently does.

jalubarsky

Makes sense, I will try to do so in very small increments.
Thanks.

neilc

if you look close at the Ptrol picture you can see the pendulum just left of its plumb mark,
damn close but you never know , , ,
watch that for a pressure cycle and make sure it doesn't swing,

neilc

hey,
wait a minute,
how come the lower 30# gage is at 7,
and the 3# on the pigtail is zero ?
is piggy clean ?

neilc

ok,
I just read "new pigtail",
how about the iron fittings back into the boiler, they clear ?
why are those gages so far off ?

jalubarsky

The 30 gauge registers 7 at zero and always has. I added the 3 psi gauge after first cleaning out the elbow and then adding the new brass pigtail and new fittings. I thought about replacing the 30 gauge but after having a hard time removing it I stopped before I snapped the brass.