2 stage gas valve setup

dabrakeman

Would anyone know what I would need for a gas valve and maybe a vaporstat if I want to replace my current gas valve with a 2 stage gas valve? I have a Weil-Mclean EG65 steam boiler (one pipe). My current valve for the second year sounds like it is about to go with all the buzzing noise it is making. Did it last year but then stopped after a few days or so and didn't come back. This year starting out doing the same thing. I have been considering upgrading to a 2 stage valve because I have a bit more boiler than the house radiation can handle at least on very cold winter days and 1+ degree recoveries. I think this would be the time to get something on the shelf at least waiting for when this valve actually goes, rather than starting a search in the middle of the next winter cold snap. My thought is to have a system that would switch to low fire when pressure reaches some threshold, ~1psi?? In the winter mornings if doing a 2 degree recovery it can bounce off the 2psi cutoff a couple times. I just don't know exactly what all components I need and how to know they are compatible with my boiler?

Dave0176

I'm assuming the boiler is oversized. Where are you located because it be best to hire a contractor because the after the install you need to do a combustion analysis and gas pressures need to set on hi and low fire. I've done many and everyone needs adjusting.

EBEBRATT-Ed

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

dabrakeman

Weil-Mclean EG-65 steam. Yes, it is oversized relative to the radiators and pickup. Located in Michigan between Lansing and Detroit. Haven't found too many contractors in the area but yes I would still find someone to do the actual install. I really just would like to know now what I could use.

dabrakeman

Current single stage valve on this boiler is Honeywell VR8304P4348, Weil McLain part number 511-044-383. Also compatible single stage is White-Rodgers 36C74-474.

Just wondering if that helps identify a compatible 2-stage? White Rodgers does sell a W36H64463 2-stage 24V 3/4"x3/4"? Anyone know whether that would work?? Or, the Robert Shaw 720-082?

Fred

Sent question to a Weil Rep, this is his response:

"Thanks for submitting your question about the Weil-McLain EG-65-S-PIDN - 157K BTU - 83.0% AFUE - Steam Gas Boiler - Chimney Vent. Please see our response below.

Q. Does this unit come with a two stage gas valve either standard or as an option? If it is an option, what gas valve is used?

A. Wouldn't be an option, Fred, I apologize. See attached for the valve that comes along.


I know there is a 2 stage for the EG75 but apparently they don't suggest one on the 65 ????

ChrisJ

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

@KC_Jones kind of did...

Dave0176

The valve I like to use is the Honeywell VR8345Q4563 good for 300,000 BTU. Had too many failures with the Robertshaw valves.

dabrakeman

I can't find it now but I recall reading somewhere on this forum that the Weil Mclain reps were obligated to say it is not recommended, thus my effort to see if there was any real field experience out there with doing such.

Dave, I found the valve you recommended online and it does appear to be mostly same specs to the ones I found (from my non-expert point of view). I will recommend it for consideration to my heating contractor. Is it correct to assume having a higher capacity than needed is not a problem?

I do not want to reinvent the wheel on this forum if there are other previous forums that really adequately cover the setup process of implementing a two stage. I have read some that suggested setting the high and low stage up based upon outside temperature. Not sure that would be exactly what I was envisioning. Mine being more of an oversized boiler issue intuitively it makes more sense to me to downfire based upon pressure. I have read a couple threads referencing such with a vaporstat but didn't find anything start to finish referencing a complete and successful setup and tuning.

dabrakeman

Dave, If I get the Honeywell VR8345Q4563 valve, a L408J1017 Honeywell 0-4psi vaporstat and a low pressure 0-5psi gage I have a few related questions below. Very much appreciate anyone's input;
1) Is the L408J1017 an appropriate vaporstat?
2) would there be any recommendations on initial adjustment of the vaporstat?
3) should the existing pressuretrol be replaced or somehow kept in series with the new vaporstat?
4) by code does the 30psi gage need to be kept alongside the new lower pressure gage? If so does the low pressure gage need some kind of protection from higher pressure?
5) Are the stages in the 2-stage gas valve pre-set or adjustable? If adjustable how to determine the low fire setting gas pressure? IS this set/limited by the combustion analysis or is that unrelated?

I know there are alot of questions here. Maybe it is a rainy day where you are and you have nothing better to do?

dabrakeman

Perhaps I am asking painfully obvious questions relative to something quite straightforward or I am proposing something totally not recommended, don't know which. Really hoped to get some more detail back from the forum so will try one last time starting again with the reasons I am proposing a 2-Stage gas valve with low fire triggered off of rise in steam pressure.

1) Current gas valve still buzzing - Very annoyingly so likely needs to be replaced anyway
2) Sizing - My standing radiation with 240 conversion factor and 1.33 pickup factor is 159,495. My boiler EG65 has output of 209,000btu. In real usage the three upstairs bedroom radiators are purposely turned off. Too hot when on at all. Thus normal radiation is 133,680. We are also empty nesters and really never use two other rooms in the house that are easily closed off (a sunroom that is original outdoor construction so that it would not be affected by cold, and another room that has two radiators and at least one could be turned off separately). Radiation load could be as low as 84,588. So I am oversized anywhere from 31% installed to 56% as used today to 147% potential.
3) My winter gas bills average $2600 per heating season. If I could cut consumption 25% I could easily save $650 per year. So my payback should be pretty quick.

nicholas bonham-carter

Check your main vents first, after adding the 0-3 psi gauge along side the standard 0-30 psi gauge.
As the system begins to make steam, watch the pressure rise as air is pushed out through the main vents. If it goes above a few ounces, then your main venting capacity is lacking.
After the air has been removed, of course the pressure will continue to rise as the oversized boiler is producing more steam than can be condensed by the radiators, and this is where the 2-stage gas valve will help.—NBC

dabrakeman

Thank you Nicholas. I can do that initially and get the low pressure gauge in. I guess the fact that a 0-30psi gauge stays pegged at zero really doesn't mean anything when you are loooking for ounces. My main venting by the way is comprised of 2 Gorton #2's + 1 Ventrite #75 on one main and 1 Gorton #32 + 1 Ventrite #75 on the other main.

So you are suggesting that the low stage be calibrated to initiate on 3-4 ounces?

dabrakeman

Gorton #2 not #32 (mistype...)

ChrisJ

@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.

dabrakeman

Sounds great Chris! I have not been able to measure pressures at that low level yet since I do not have the proper gage but I suspect I don't have pressure issues of any significance until my radiators are full and stat is still calling for heat. I think my main venting is fine and steam gets from the header to end of mains quick enough. Pressure only builds when very cold or recovering from a setback. Boiler will shutoff at ~2psi. I also suspect that after the steam collapses and the boiler comes back on that my mains are still hot and don't reopen which can't help anything relative to the inefficiency of that 2nd short cycle.

I have tracked for years my gas use per heating degree day and it is quite clear that my overall efficiency declines as the heating degree days go up (when it gets colder).

Fred

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?

dabrakeman

Fred,
My standing radiation (all radiators) is 531sqft. Teh 240 is just the conversion factor for one sqft of steam radiation to net BTuh. In my normal usage scenario with the bedroom radiators off the total sqft of radiation is 419 sqft.

Fred

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).

dabrakeman

Fred,
So is the L408J1017 an appropriate vaporstat and does it replace the existing pressuretrol or does the pressuretrol stay in there in some backup manner?

BTW the bedroom temps are certainly not going down by turning those rads on and they are warm enough off. Thermopane windows upstairs, original historic windows down...

gfrbrookline

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.

gfrbrookline

Lets go back to NBC's post about venting the mains.

How long and what diameter are they. You have large vents but they may not be enough.

Fred

@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.

dabrakeman

Until there's some funding support for historic homeowners replacing windows downstairs is not going to happen. Been quoted in the neighborhood of $75,000. I'll let you guys do the payback on that. I probably won't live much beyond 200 years old:)
Heat is balanced perfectly in the house, just don't need a couple of those rads on.

Dave0176

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

@gfbrookline,
Old string few years back has most of the info you are looking for. Time to get steam to end of mains is pretty good, less than 4 minutes.
https://forum.heatinghelp.com/discussion/153121/main-vent-reopening-temperature

dabrakeman

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

ChrisJ

@dabrakeman obviously it depends on the length of the mains and insulation, but I'm able to get steam down to the end of my 29' main in just under 60 seconds if the piping is hot.

A good test for main venting is to fully heat the pipes and then shut the boiler off for 10 minutes then fire it again and time it while monitoring back pressure. It's extreme conditions but that's about what my system sees when it's below zero out.

Dave0176

dabrakeman said:

@Dave,

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

Not a problem that’ll work fine......

gfrbrookline

Thanks for the link, that was one of the ones that I used to balance my system. Two mains, one with three big mouths the other with two plus one G2 to balance. Hot side of the building has G4's on rads cold side has G4's, G5's and G6's depending on floor and room comfort. All is balanced since the windows have all been replaced 99% of the time. The only time we get out of whack is when we have a Noreaster and the wind slams the east side of the building, can't correct the heat loss of the bricks.

I feel your pain on the historical requirements. Went through it years ago trying to install low e windows. One branch of government is pushing you to improve your energy efficiency the other is trying to hold back time. I get both but there needs to be a compromise.