Single-pipe woes

Fizz

Recently insulated back-side of parallel flow system, changed main vening, switiching-out MOM 1's on each main to Gorton#2 on back-side, and 2 Gorton#1's on front. Result, faster steam getting to end of main, but increased pressure and heat swings. Realizing we're in the middle of cold snap, single digits at nite, system seemed more manageable with no insulation and less venting. Thinking a 3cph t-stat might be appropriate. Currently have t-822d, and no matter where anticipator is set no improvement. Current setting is at lowest setting, which is higher than control unit Genysis 7505 amp rating of .1

Fred

- Have you rebalanced the radiators since you insulated and put the new vents on?
- - How over sized is the boiler? If it is considerably over sized, the insulation has caused less steam condensation getting to the radiators and that may contribute to the increase in pressure.
- Do you have the Pressuretrol set at .5 Cut-in and 1PSI differential?
- Are you sure the pigtail is clean?

I would set the anticipator back to where it was before you started adjusting it and rebalance the radiators and check the other items on the list above. It is also possible that you are going the wrong direction with the anticipator.

JUGHNE

I had this happen on a larger single pipe system.
2 mains totaling 220' of 3" pipe.
Used to run 3-7 oz. cycled by t-stat only.
After insulation would run up to more than 1 PSI, leaks showed up at valves etc.
Added vapor stat and more G2 main vents on each main, total of 5 on each.
After that it would seldom cycle on pressure.
EDR was a close match.

Fizz

Fred, haven't re-balanced since other side insulated, boiler is SGO-3, 354sf EDR, attached rad is 220; yes to p-trol question. As for anticipator, shouldn't it match or close as possible to boiler control amps?

Fizz

EDR is 220, boiler 354, mains are 2" of about 25 ea side, and 11/2" of 30' ea side.

Fred

Fizz said:

Fred, haven't re-balanced since other side insulated, boiler is SGO-3, 354sf EDR, attached rad is 220; yes to p-trol question. As for anticipator, shouldn't it match or close as possible to boiler control amps?

Sounds like the main venting is ok. As for the anticipator, that's typically the instructions provided for forced air. I'm not sure that always holds true though, especially for steam:

"Many non-programmable mercury switch thermostats have a heat anticipator switch to help operate the furnace. The heat anticipator cuts off the furnace, but not the blower, in "anticipation" of the heat left in the furnace that has not come through the vents. This allows the furnace to operate efficiently. When the furnace is cutting on and off too often or the room is not reaching a desired temperature, it is necessary to adjust the anticipator. "

Fizz

I'm wondering if the fact that the boiler is oversized has anything to do with issue?

ChrisJ

If your boiler is oversized and you insulated the mains you want as much main venting as you can do and short thermostat swings.

2-3 CPH might work well, or on a mechanical thermostat a shortened anticipator setting, I.E. lower number.

Fizz

Thanks Chris!

Fizz

Yesterday I re-vented mains, moving G2 and MOM-1 to front, and 2 MOM-1's to back, resulting in back getting steam to vents quicker! Timed steam from cold start, with steam full at header, took steam 10' to get to back vent, and 15' to front. It seems the less I vent the quicker getting to main vent. Rads start heating soom after steam gets to their feed. Another anomoly is steam starts down drop to boiler drip before heading to vents. Vents are on antlers. This anomoly has been present from moving in to house back in 3/18. Strongly considering a MOM-1 or G1 on each main and going to mechanical t-stat with lower anticipator setting, either White-Rodgers 1E3ON-910 with settings from .15-1.2 or Robershaw 986-1 with settings of .1-1.2. Current t-stat is mercury T822D, with .18 as low setting. Current control unit Genysis 7505 amp rating of .1. Any thoughts? Jamie, I know this violates the bible of mercury t-stats.

nicholas bonham-carter

Time the steam from a hot start, and see how long it takes. The Gorton 1 is good for only a 10 foot length of main, so you may need some Big Mouth vents on each one, which will do for 50 feet of 2 inch pipe.--NBC

Fizz

The side with 2 MOM1's vented 4' quicker than with the G2 and Mom1; and when reversed, the slower side with smaller vents got to vent about 10 sec sooner.

Fizz

I was thinking of plugging main vents which have approximately 50' of wasted steam, and letting rads vent supply main, and keep return mains closed thereby not having to vent needlessly. When I had a G1 on each side the steam never got to vents but rads heated quicker.

Fred

You don't want to let small radiator vents try to do the job of main vents. You are not wasting steam by heating the main pipe that has no radiator run outs on it. That's the way your system is designed and, like it or not it will use some steam to heat that main. You can minimize that by putting your main vents as close to the last radiator run-out as possible but it isn't a priority. The question/issue that needs to be resolved is why does your main heat faster without main vents than with them or with smaller main venting than with larger ones. The answer may be that you have such large vents on your radiators that the steam starts down the radiator run-outs before it fills the mains. That leads to uneven heating in the living spaces and you will never get all the spaces balanced.

Fizz

Here is venting for rads: back side-wall type 9sf gorton5, collumn 30sf MOM5, coll 24sf G5, iron tube21sf MOM4; front col42sf MOM5, col33sf GD, It 21sf Heat timer 1/2 setting and col38sf MOM6. I used table from Gerry Gill and Steve Pejak as guide.

Fred

That Heat Timer alone at 50% vents faster than a Gorton #1 Main vent. You are making the steam flow far easier to go to those radiators than to get to the end of the Mains. When the larger radiator vents close from steam, then the steam flows to the end of the main (next easiest path).

Fizz

Actuallly I have it at about 1/4, it's 2nd floor and the last run on front main and last to heat.

Fred

Fizz said:

Actuallly I have it at about 1/4, it's 2nd floor and the last run on front main and last to heat.

I stand by my original comment. Based on the way you have the radiators vented, the steam will not fill the mains before it starts to flow out to the radiators. No way to balance the system. The Heat timer is too fast, a Gorton D vents at the same rate as a Gorton #1 Main vent, A gorton C is not much slower that a Gorton #1, Steam can easily go all directions and eventually end up at the end of the main, if the boiler runs long enough.

gfrbrookline

There are very few steam systems that benefits from heat timer vents. They were a good concept but they vent way to fast and only add to balancing problems. Try a Vent-Rite #1 that can be easily adjusted and see how you make out.

Fizz

Thanks guys! Here are numbers I got for each radiator's cubic feet of air using Gerry Gill's chart for balancing a steam system:
Front side- 1.05; .825; .525; .94 =3.339
Back side: .252; .75; .60; .525=2.13
What would be proper size rad vents?

Fred

Fizz said:

Thanks guys! Here are numbers I got for each radiator's cubic feet of air using Gerry Gill's chart for balancing a steam system:
Front side- 1.05; .825; .525; .94 =3.339
Back side: .252; .75; .60; .525=2.13
What would be proper size rad vents?

Try the Vent-Rite #1 that @gfrbrookline suggested. They are very reliable and can be adjusted to address the spectrum of needs from "off (or near off)" to 0.083 CFM at 1 ounce of pressure (in eight incremental steps). A far more appropriate venting range for radiators.

Fizz

Ok, thanks Fred!

Fizz

Just bought big mouth and switched-out G2, now have Big Mouth and Mom1 on slower side, and G2 and Mom 1 on faster side. Results basically same as quick side steam gets to main vent quicker, with steam getting to slow side somewhat quicker than before. Next move to get some Vent-Rites.

BobC

The radiator vents have to be replaced with reasonable sized vents, the VentRite #1 is a good choice, you want to vent the mains fast and the radiators slowly.

If the balance problem between the front and back mains persists you could try pulling the G2 that you have on the fast side to see what that does.

Bob

ChrisJ

Slow the fast side down more.

Fizz

Thanks Bob and Chris. Was thinking of replacing G2 with Mom1.

Fred

@Fizz Don't replace the G2 with a Mom. The slow side is likely slow to get steam to the end of the main because the combined venting on the radiators is so fast that steam is taking a detour and running out to various radiators before it travels to the end of the main. Slow those radiators, on that main down, then see what the timing is to get steam to the end of the main. You can artificially slow the fast main down, even to the extent of taking all venting off of it, but that's not the goal. Vent mains fast and radiators slowly.

ChrisJ

Fred said:

@Fizz Don't replace the G2 with a Mom. The slow side is likely slow to get steam to the end of the main because the combined venting on the radiators is so fast that steam is taking a detour and running out to various radiators before it travels to the end of the main. Slow those radiators, on that main down, then see what the timing is to get steam to the end of the main. You can artificially slow the fast main down, even to the extent of taking all venting off of it, but that's not the goal. Vent mains fast and radiators slowly.

I have Gorton Cs on two of my radiators, and 6's , 5s etc on others.

I most certainly slowed the venting down on one of my mains.
I have 5 G1s on one main and a single G1 on the other, though I had a Hoffman 4A on it for a bit and considered plugging the vent tapping.

The "vent mains as fast as possible and vent radiators slow" rule isn't that cut and dry if you want perfection.

I can get steam to my radiators in under a minute on a cold day and all 10 will get steam within seconds of each other, consistently.

Fizz

On the slow main(well vented), I have a heat timer set at 1/4at end, 2nd fl and it's the last to heat, tho it heats good, the others are G5,6 and mom 6; quick side has mom 4, Homart(4 equivalancy), G6 and Mom 4.

gfrbrookline

I agree with @Fred and @BobC that you are venting the radiators on the slow side too fast. I concur with @BobC on the Ventrite No.1, swap out the 6's and Heat timer, the 5 should be fine although you benefit using it in place of the 6 on the other side. You can easily fine tune the Ventrite to balance the radiators. Slowing the radiators down will let the main fill before the steam shoots up the risers and make the heat distribution much more even.

Fizz

Thanks for your input. I will be switching-out as soon as I can make purchase. In the midst of house closing on prior house which has Richardson System I put in vacuum and it's fabulous. That alone keeps me questioning my move to downsize.

Fizz

Recently switched-out G2 from quick side so it's serviced by MOM#1 only, so steam gets to end of main on what was slow side about 4' quicker now, with 10' to get to end on cold start. Reluctant to change vents of rads affecting t-stat. They are Mom 6, and G5.
A question, is it common for a Big Mouth to waft steam for about 30-40 secsinitially on stear arriving; also felt steam coming-out mid-way through cycle lasting about 1'?

nicholas bonham-carter

Are you under the 2 ounces of backpressure while the initial venting is going on-that’s the key for simultaneous steam arrival at all the radiators.
It’s the radiator vents which need slowing down.—NBC

Fizz

Yes, pressure is under 1oz until about the final 4-5 min of cycle. On the less vented side, the vents are Gorton 5, Homart 4, and 2 mom 4's. On other side, Mom 5 in room with t-stat, Mom 6 bedroom above, G5 on room next to t-stat, and heat timer above set at 1/4.

nicholas bonham-carter

If you have any more problems put Hoffman 40’s or 1A’s on all the rads.—NBC

Fizz

Beginning to see biggest problem is time it takes to satisfy thermostat. On real cold days, o-10, run is 40-50', on days in20's about 38-42 and 35-40 degree days from cold start 32-37'. House is a small(1150 sf) cape cod style, and t-stat is in living room which ajoins kitchen. The rad heats fairly quickly and fully, but long runs for t-stat sate.

nicholas bonham-carter

Are you using temperature setbacks? Try setting the thermostat to a constant lower temperature, and leave it there. That will result in greater comfort and economy, especially with your questionable main venting.—NBC

BobC

@Fizz I live in what they call a new england cape (12 ft dormers on front and back roof). It's like trying to keep the water out of a sub with a screen door on it. The walls have blown in insulation but it really doesn't help much. The only way to do it would be to strip it down to the studs and foam everything.

No problems with radon here, anything that gets in doesn't stay long. The house is just about 100 years old and I'm 72 - a strip down to the studs ain't gonna happen in my lifetime, that is one of those "next owner" jobs.

Bob

Fizz

No set-backs, NBC, keep T-stat at 70. - Fizz

Fizz

Think you're right-on Bob. We moved recently(downsized), and the house is money-pit. One of reasons for leaving was maintenance; guess I didn't do homework. Good feedback as was thinking of insulating, but at 71?????

BobC

Make sure the attic well insulated (tear up a few floor boards if you can) and seal the area around the foundation where it meets the rim joist. I bought a new set of tower speakers several years ago and they came very well packed (from China) so I was left with a qty of 1 to 1-1/2" closed cell foam sheets.

I cut it up and fit it between the joists against that rim joist. When the insulated they also sealed up the basement with spray foam. They had a 30" long SS tube with a nozzle that was fed by a large can of spray foam. The quieted the drafts downstairs a lot. I also close the two doors that lead to the downstairs hallway to keep the heat downstairs from rushing up the stairs. That keeps the upstairs about 5-6 cooler than the first floor which is fine with me.

Bob