2 stage gas valve setup

not all boilers can operate 2 stage. what do you have??

Plenty here have installed 2 stage setups on the EG series.

@KC_Jones kind of did...

@dabrakeman A 0-0.5 PSI gauge barely moved on my system.

The highest I see all winter is 0.036 PSI and every radiator heats fast and if need be, completely.

Before the main vents close, my pressure is around 0.009 PSI at the boiler.


Just to give an idea of just how low a single pipe system can operate.

Double check your boiler numbers. It will tell you exactly how many EDR the output is. Compare that to your 240 Radiation EDR. The 159,000 BTU number you quoted as output for your boiler I believe already has the 33% piping and Pick-up factor calculated into it (Boiler input minus Boiler efficiency, minus Pick-up factor = BTU and or Sq. Ft. Steam (EDR) output).
I think you may be adding another 33% into your equation which means your boiler over-sized more than you think. How did an EG-65 ever get installed for 240 EDR?

Got it. I miss read your post. In any case, you don't have to convert EDR to BTU's. Just compare the EDR to the stated Sq. Ft. Steam on the boiler plate. Anyway, to your real question:
Several of the Pros here have installed a two stage gas value on boilers with standard single stage valves. It can be done and is effective. Just make sure it is installed by someone who knows what they are doing and who has the equipment (combustion analyzer) to properly set it up. I believe @Dave0176 even told you which one he likes to use.
Closing off radiators is not the fix for over heated rooms and it is not likely to save you any fuel cost. Those bedrooms are hot because you haven't balanced your system. Main venting is the first step. Make sure you have enough vents on each main to get the air out quickly. Once that is done, each radiator needs to have a vent on it that is appropriately sized for the amount of heat you want in each area/room. Using adjustable vents like the Vent-Rite #1, the Hoffman 1A or the Maid-O-Mist will allow you to adjust each vent to your liking. It takes trial and error but you can even out the entire house.

You already know that your boiler is over sized, why compound the problem by shutting any radiators off? Even with a two stage gas valve, shutting enough radiators off will still cause short cycling, even in low fire. Eliminating the short cycling is where you will likely see the most fuel savings as you can create a steady flow of steam to where it is needed and to satisfy the thermostat and not have the stop (steam collapse throughout the system) and start (steam has to start a flow again).

Your window combination may be problematic, especially since the more energy efficient ones are upstairs.

I have the L408J1017 vaporstat and am very happy with it.

I would suggest Gorton No. 4's for the upstairs radiators. These will slow them down and help balance you out.

My building had a mixture of low E and older aluminum replacement window and the heat could not be balanced properly until all of the windows were upgraded.

@dabrakeman , yes, that is the correct Vaporstat. The Pressuretrol does stay on the system and acts as a back up. The Vaporstat, Pressuretrol, and Low Water Cut-off are all wired in series.

Yeah the EG55 would’ve been a lot better for you, but since the 65 is new and already there. As I said before I like the valve I mentioned and the Honeywell vaporstat you mentioned. However those vaporstats need to set on water column test gauge to be sure their working where you want them. The numbers on the two scales unfortunately do not work accurately. The low pressure gauge I like to use is a Wika 0-35 oz.

As far as installing them on the boilers both Weil-McLain and Peerless both said they don’t recommend it and it will void the warranty. This was from the reps of both companies. That being said it is what it is. The only warranty the manufacturer has anyway is a 10 year manufactured defect on the boiler block only. You are warranted for a year on the all other components installed.

dabrakeman said:

@Dave,

I have a Wika 0-3psi on the way. That won't be sufficient?

Not a problem that’ll work fine......

@Dave0176 little reboot of the thread here.

my results with Williamson GSA-125 have me thinking about two-stage already. my rough EDR calc was 260 so the 315 of the GSA-125 gives me 20% pickup but this system is tight enough and the empty nest habits for closed radiation mean it is very quickly short cycling at full fire. even if i go nuits with more/bigger vents i'm really not in that much of a rush and have noticed that a nice low fire fills the system about as fast and with much dryer steam.

just by manual restriction i can set up a nice low fire that keeps the radiators all steaming at norm house temps so high would be reserved for cold starts and clawbacks. I didn't have my manometer or combustion meter so I'll check the numbers but the honeywell valve you linked has nom low fire pressure of 1.7 inches of water, (half the standard 3.5 inches).

now everyone talks about adjusting. when I did this on a burnham commercial 8 section I checked combustion at high and low settings but mostly the adjusting was around output. (these side saddle atmospherics I am inserting the combustion probe through the craft hood and into the top of the boiler. I tried a few locations on the burnham and got pretty consistent result. I suppose I could pop the top and drill the bolted on exhaust collector/leader to the draft hood and make a little plate or just a little red silicone to fill that hole when not in use but I haven't really seen anyone suggest a particularly effective location other than upstream through the draft hood). the honeywell literature indicates the stages are adjustable but it doesn't indicate a range. (for that matter I might want to adjust the high as well which has an adjustment but again doesn't indicate the range. It maybe be that they kind of intend the ranges to be fixed around those numbers but give you a little adjustment. I could live with that but I have to stop and think if half the pressure delivers half the btus. not sure it is linear relation and might be dependent on the choke points in gas delivery to the burners.

The air intakes are fixed with the amount of air entrained being managed by the extent of the flow out of the orificies. So this is pretty much like changing the flame level on your stove burner. I was checking combustion to make sure that the alteration didn't produce a notably create an undesirable CO or efficiency that couldn't be carefully enough inferred from just observing the flame, but otherwise the adjustment was actually aimmed at regulating the flow to just maintain low steam pressure to continue just steaming the system and make up for condensation. I did this with a larger 2-stage honeywell valve with 1" ports for that larger burnham commercial. That was maybe 10 years ago and I can't find the number of the valve I used in my old emails at the moment.

also the wiring instructions in install manual for the VR8345Q are impoverished, partly because the install manual is for the Q and M and H vairants so both single and dual stage valves. I assume the Q it has a 24V common and two 24V calls one for high and one for low so the stages are independent although its conceivable that you could also design something like this to call the low fire all the time and then have an equivalent stage so calling them together gives you high fire. the manual shows the pilot wiring well for intermittent pilot but it doesn't show the two stage connections for the actual valve operation-only a one stage setup, which many of the valves in that line are one stage.

as far as control, I knew you could use a staging thermostat or inferential maybe rate of rise staging with tekmar style steam controls but IIRC those aren't staging on what i really care about, steam pressure. if the tekmar had a vapor sensitive pressure input and learned the rate of pressure rise by cycle time and maybe comparison to indoor and/or outdor temp it could decide what was a useful time to turn down. That would be cool, but I don't think that is what it does.

Because you want the turndown often before you start to see changes in room temp I'm ruling out staged themostats. So I'm pretty much going to use the manufacturer supplied pressuretrol to run the low fire where it really is more a limit and not operating control and set a 3 lb cutout and i'm planning to adjusting low fire as I have manually in test to accomplish nice balance about 8 0z of steam which fills the system and keeps it steaming under normal circumstances, i.e. not cold start or clawback. So i'm going to use a L408J1009 I think to turn off high fire. Getting good vapor control is difficult but I think that is about the only option these days with any kind of differential. In the lost archives of heating help there was a collaboration to design a two stage operating control using dwyer gas pressure sensor switches that used two of them and a relay to create the differential but unless the L408Js are virtually useless I'm thinking that is the simple approach for this job. there are still a few L408Bs out there but if the L408J can really go off at say 12 inches with a subtractive differential of 8" I think that would mean i'm not going to be short cycling the high fire.

thanks for ideas from anyone who has added this option.

brian