New vs. Old Boiler Energy Use Differences Suprising to Us

Part of our research was that the old EGH-85 was an older series ( 4?) than our new EG-75 (5, I think), and WMC told us they reduced the heat output between those series after a review by the Dept. or Energy or something like that. That had them telling us the old series EGH 85 was equal to the new series EGH-95 or EGH-105 today. After counting & measuring all the rads, we thought the current EGH-75 was big enough-some say we should have gone with the EG-65 to get a less than 32% pickup factor. Here's a pic of our only wet return area next to the boiler. All 3 dry return loops coming back to the boiler room at the ceiling of the basement 6-7 feet up from the floor until the drop next to the boiler shown in my avatar pic & here. Was shortening the wet return lines by 5-8 feet with the new boiler a problem if it now doesn't have enough reserve water capacity? The condensate seems to return about 5-6 min. after low-water shut off this season (at least prior to our skim last week).

Ok, we made a list of about a dozen things the water loss & higher energy use could be caused by, and replacing the last 4 long line gorton D/maid-o-mist D radiator vents with new ones (or smaller hoffman vari-vents) on that 2in loop we're planning on splitting sounds like the easiest first way to see if that was the problem with 1 gal/day water use.

Some people advised against such large D size vents on 9 EDR (1 wall hung), 25, or 40 EDR size 4-5 old column style radiators. Is the theory that too fast a vent allows too much steam & condensate in the rad, causing vent failure & possible water loss through the rad vent?

On the other hand, we made up half the difference a split in that 2in long main loop would make just by adding 4 D size vents to the last 4 rads on that long line if they can stay functioning where they are.

After looking at our boiler again today, we notice it starts the igniter, short loop with first rads gets steam 4 min after ignition, long loop with last rad steam established 9 min after ignition, then shuts off 10 minutes after steam established on long loop, so 19 minutes total run time with available water supply or from tekmar on 27% boiler % with our 40 min cycle.

This suggests tekmar shuts the boiler off naturally when weather is above 30F or so, but in colder weather it would need to run more than 10 minutes, so we're interrupting the steam production & losing several minutes of steam at the end due to running out of water, right? Is this the short cycling that uses 30% more energy than if it could run several minutes longer using the tekmar specifications without low water interuputions? Heating those pipes again seems wasteful as we're effectively making 2 shorter cycles instead of 1 adequately long one since it has to wait 5 min for the condensate to return after shutting off, then is still 1/2 inch low due to rad leaks & waits for both the cycle to end 40 min after ignition and then more time for the lockout differential to fall a few more degrees before starting up again since the tekmar only allows one start & stop per cycle. While the last week was only 5F it still heated the rooms 65-68F, so does this also prove our boiler is large enough if it can keep up with no more than 19 minutes run time each "short"cycle?

Does tightening the packing nut simply mean using a wrench to tighten the first nut below the top of the shut-off valve at each radiator if it's loose? If we add the handle if it's missing on top & it spins loosley after tightening the packing nut below, does that indicate the packing washer needs to be re-packed with that rope-type material we read about?

Here's a pic of our typical radiator shutoff valve areas (about half are missing handles). This was the one our tennant mentioned & it had water leaking down the stem today, so we suspect this is part of the problem.

Thanks for the suggestions & advice everyone! I think we'll visit all the rads as our next step and see what we can find. Is the list below a good way to proceed as we visit each one?

1. tighten packing nut if lose
2. Add teflon plumbers tape to bottom of shaft on top of nut & turn handle (after adding a new handle or just use a pliers) a few times to work it down in there to seal the gap with 3-4 applications of tape
3. If it still feels lose with the handle after this & spins without some tension, add rope to re-seal the washer (is boiler shut-down needed for this step?)
4. If this doesn't work, replace the whole valve after measuring what size replacement we need & shutting down the boiler (simply use a pipe wrench to remove the union on the radiator side, then remove it from the vertical riser?) If we're doing this, would be want to try and clean out the bottom of the radiators as well somehow, or just leave them alone?

In the meantime, we could try adding a few steamaster tablets into an open port (or 8-way?) like the skim port per the manufacturer's instructions. Since we can't boil more than 20 minutes or so with the current leak before low water cutoff occurs, we won't be able to do the full 1-3 hr steam cleaning treatment for dirty boilers, just the maintenance level one per the product sheet instructions? Are there any risks to adding the steamaster tablets or 8-way to our system? (Smelly radiators, clogs, etc. other than being careful handling the product)

Thanks Fred. Might the temporary teflon tape fix get us by until the heating season is over for replacement of the entire valves if the simple tightening of the nuts doesn't stop the leak?

I called Hoffman/Xylem/Gossett and they said they no longer make iron/black steel valves, so just the brass ones I saw at supplyhouse seem available so far. Is brass ok with our current iron risers & radiators to avoid diaelectric union issues? They come with a short nipple pipe-is that the spud you mentioned?

When we observe the Hoffman vari-vents & Gorton C & Miad-o-mist D rad vents, they should release air as steam fills the rad for a few minutes, then shut off & be silent until they open again when the steam condenses in the rads several minutes later? Maybe a pop or closing sound as they open & close? Other than that, no other sounds from them? If we notice sputtering, water gurguling sounds, constant noise, or water leaving them, they need cleaning or replacement?

Thanks-we're heading over there now to check out the apartment rads. All new vents since new boiler install in Nov. 2015. We just got a text that spitting rad in bedroom unit #1 is better now since we replaced it 2 days ago, so we'll see how it looks again in a few minutes.