vaporstat vs pressuretrol

Phil_17

I have also been thinking of replacing my presurtrol with a vaporstat. Started with adjusting vents in the radiators and mains (still working with a really old boiler), but now that I've got things balanced pretty nicely the 0-30 psi guage never moves the needle. The burner just runs and runs and runs until the thermostat calls it quits (tested up to an hour). I've got a new guage on the way (0-5 psi) and plan to do a little more research before plunking down the cash for a new control, but if the evidence shows that I could be cutting off on pressure of a couple ounces (instead of burning 1.5 gph) then I would think that it shouldn't take too long to get some payback on $170

I found a few places selling them with a google search. Looks like you may be able to do much better than $240. Here's one:

http://dticorp.net/catalog/honeywell-kgcm2-p-1137.html?osCsid=f73dff23c0acf983fa32347c8014739b

This is what we all are talking about, isn't it?

Jim_101

vaportstat vs pressuretrol

What are the advantages and disadvantages of using a vaporstat compared to a pressuretrol? This is for a residential one pipe steam system.

Are vaporstats reliable over the long run?

Are there residential steam systems where a pressuretrol would be preferred over avaporstat?

Thank you.

Brad White_147

If I had a steam system

I would have a Vaporstat. I would be willing to pay $300 rather than $100 for the benefit.

The benefit is that a Vaporstat controls to ounces of pressure, not lbs. and ounces are probably all you will need.

I would want to run the lowest pressure possible and control that pressure within a proportional band. This means ounces either way.

Think of a pressure gauge:
Imagine using a 0-100 PSIG gauge to read a pressure of 5 PSIG. Hardly enough scale to be considered accurate, being at the bottom 5% of the scale. Get a smaller gauge, 0-30 PSIG. Better, but you are still in the bottom 16% of the scale. Go to a 0-15 PSIG scale. Still not there, see?

Now, a 0-10 PSIG gauge will put you smack in the middle, a good selection. I exaggerated the scale for the sake of illustration, but I think you get the idea.

With a pressuretrol, the units are in pounds, not enough scale of accuracy for me. A factor in units of 16..


Systems where a pressuretrol would be preferred would be process and central heating boilers, HP boilers such as hospitals where low pressure steam generally runs about 8-12 PSIG, medium pressure runs between 15 and 60 PSIG and high pressure could be 100-125 PSIG. Talking pounds now.

Utility plants and generation plants can run from 400 to 2,800 PSIG or more so forget vaporstats....

Such systems run to maintain pressure as a constant setpoint, the return being a separate path with it's own agenda.

In one-pipe steam, cycles are necessary to return the condensate. I would far rather pump the system up to six ounces and let it drop from there, than let it cycle up to the 3-4 PSIG range and release that. (I confess to once owning steam systems and operated them ignorantly in that range, figuring more pressure was better. Thanks Dan, for allowing me to learn better.)

Jim_101

Thanks Brad

I was thinking the same thing, that more pressure was better. That is what my service company has been telling me for years. I needed the pressure to push the steam up to the second and third floors of my house.

It's just hard for me to imagine I can run a steam system on ounces for pressure instead of 1.5 to 2.0 pounds after all these years.

Will the system use less oil?
Will I get enough heat?

Steamhead (in transit)

Yes and yes

The Dead Men designed one-pipe steam systems so they would never need more than 2 PSI at the boiler, on the coldest day of the year in a house that had no weatherization whatsoever. They also wanted to be able to circulate steam on a few ounces and fill all the radiators on that pressure.

I'm assuming your house has insulation and window upgrades, weatherstripping etc. So your system can run at even less pressure.

Get the Vaporstat, the one that only goes up to 1 pound.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

brucewo1b

Jim

If you find the sweet spot yes you will have enough heat and its not the amount pressure but expansion of water to steam that forces the heat to the radiators as long as your venting is correct. they heat the Empire State abuilding on I think 3-5 Lbs so why wuld your house need that much. Steam expans about 1700 times and will fill those mains and radiators as long as you can vent the air out ahead of it.

Brad White_147

Empire State Building

Not even 3-5 lbs., Bruce.

2-3 lbs.! Three on the colder days according to the building facilities engineer... And the building was warm enough to comfort a giant gorilla at one time, I am told.

Still- your point is made- MUCH lower pressure than many would ever think. Hope this was not too pedantic.

Brad

brucewo1b

I knew you had the

exact numbers but I was playing it safe, thnaks for the addition Brad

Bruce

Jim_101

Bruce

What do you mean by the sweet spot? Do I have to play with settings (cut-out and cut-in) so I can get enough heat?

Steve Garson_2

Vaporstat

As a home owner, I speak speak from experience: my new boiler was installed with a pressuretrol which I replaced two weeks later with a Vapostat. I heat mt 2800 sq foot home with 4 ounces of pressure. Shorter cycles and less oil used. Also reduced the sound coming out of the vents.

Jim_101

Are vaporstats

a stock item? What is the manufacturer and part number I should be asking my service company to install?

brucewo1b

Jim

You should be OK at 8oz cut out and 4oz cut in, but make sure you venting is right if you can't get the air out the steam will not get in.

Dan_29

vaporstats

I am looking for one also. They are difficult to find, unless your are in the trade. I checked two heating and plumbing places and two electrical supply places. They do not stock them.
I did a google search and found two places South
Side Supply (Chicago) and Alco? Supply (Pensacola,FL). They stock the Honeywell L408A-1132 Vaporstat (0-16 oz).Make sure you specify ounces as these things come in many pressure ranges. They are not cheap-$248 and some odd cents plus shipping. Maybe your local pro can get a good price.

I am still trying to justify the expense.

Dan

Dan_29

vaporstats

I am looking for one also. They are difficult to find, unless your are in the trade. I checked two heating and plumbing places and two electrical supply places. They do not stock them.
I did a google search and found two places South
Side Supply (Chicago) and Alco? Supply (Pensacola,FL). They stock the Honeywell L408A-1132 Vaporstat (0-16 oz).Make sure you specify ounces as these things come in many pressure ranges. They are not cheap-$248 and some odd cents plus shipping. Maybe your local pro can give you a good price.

I am still trying to justify the expense.

Dan

Jim_101

Dan

Thank you for the information. Sometimes finding the correct part is the hardest part of the project. Then you make do with something less than ideal, in this case a pressuretrol.

Dan_29

honeywell L408a-1132 vaporstat

It is the same unit I was looking at for more money. At the $169 price, I may consider purchasing. Thanks for the information.


Dan