Last Year Banging, This Year Short Cycle - HELP!

matthewb84

Good Evening everyone.

Newb here - worked in HVAC for a few years in high school but not much since. Familiar with terms.

I Rent an apartment in Boston, last year a new boiler was installed.

Prior to install there was your typically clanking and hissing, after new install it took it to another level. Freight Train Loud - I can upload sound files if needed. Also, always had trouble getting heat to Living Room (LR)

This year - no banging really at all but system started to short cycle. I noticed today when system turned off entirely and wouldn't refire. I had to turn on/off the main switch to kick it back on, this is when I realized the short cycle.

Pressurestrol hits 2% and turns off, manual reset light flashes and system restarts.

Things to consider.

1a. 5 Radiators on 3rd floor - system only heats this floor
1. The one Main Vent is always open (see pic) - last year it was spitting water everywhere
2. LR/Closet runs do not have a return pipe below the runs
3. B1/B2/Bath have a return pipe below the main.
4. LR will heat up but it takes HOURS
5. I do not think the boiler was skimmed after install
6. Unsure size of boiler size compared to radiator
7. Thermostat is in Living room.
8. B1/B2/Closet/Bath all Heat around same time
9. B1/B2/Closet/Bath all leak slightly from valve or coupling
10. LR vent was replaced last year - think its undersized
11. When boiler was installed last year pressure was set to 5 with diff of 1.5 ( I am guessing this is what blew the main)
12. Water (looks dirty) his That red mark around time system shuts off.

EDIT: Also - the water does look "clear" at times but then pulls dirt/soot from top of looking glass. Picture shows the dirt stuck to glass as water lowers.

Any help here would be great.

1. is there a way to stop the short cycle
2. is there a way to get heat to LR without waiting hours
3. why is the banging completely gone?
4. Anything else I should consider

matthewb84

.....

Fred

That water in that sight glass looks filthy and I don't see a skim pot on the boiler. It needs to be drained and flushed out and skimmed, probably several times to get all the oils out of it.
Also, that main vent is way too small and it clearly isn't working. It needs to be replaced a vent sized to move the air out of the system quickly. How long is the main and what diameter pipe?
Additionally, it looks to me like all of your radiators have just the 1 pipe which supplies steam and also allows condensate to return to the boiler but it looks like at least some of the radiators don't have vents on them. If that's the case, there is no way to vent air out of the radiator run-outs or the radiators. If you can't get air out, you can't let steam in. The boiler is pushing against and compressing air. If there are radiators without vents, that is the reason (at least one reason for short cycling. Also, the sight glass looks like the water is full to the top. It should only be about 2/3's full. You can't make steam if it is full. Hard to tell if it is full or if the glass is just to dirty to see the water level.
- Clean and skim the boiler
- After cleaning and skimming, only fill it 2/3's of the way up.
- Replace that main vent with one that is appropriately sized.
- Put radiator vents on any radiators that have just the one pipe and don't have vents.

Jamie Hall

It would be best to have a pro look at this one -- there are several good men in the Boston area. A few thoughts, though, on looking at the pictures. First, that main vent is a joke. It needs to be much bigger. It's also in a poor location, but there may not be much hope of fixing that. You might be able to help the poor thing by placing the new bigger vent on as tall a nipple as you can to raise it above the elbow. The living room vent may well be seriously undersized. But it is also possible that the horizontal run of pipe feeding it do not have enough slope. They look a bit on the small side for a radiator of any size, and they should slope generously back to the main. Pressure is still set a bit high; set the main down as low as it will go (that mark below the 2).

BobC

Fred and Jamie raise valid points, follow their advice. A skim port has to be installed and all the vents sb replaced. I would add a recommendation to put a level on the LR steam runout and make sure it's all pitched back to the boiler. Then run a string along each leg and make sure there are no sags in the pipe that can pool water.

I see you have a shim under one end of the LR radiator, I would try raising the whole thing up and put a 3/4" strip under the vent end and a 1/2" strip under the valve end. To lift a radiator use a couple of 2X4's, a short piece as a fulcrum and a 3-5ft piece as the lever. Put it at the center of the rad and SLOWLY try to lift the rad up. Steady pressure is the key so you don't do anything bad to what could be 100 year old pipe. Then you can slip the strips in place.

Bob

matthewb84

@Fred Great points. I think all that makes sense. The water line is actually 1/2 inch from the bottom, sight glass is so dirty and as the water drops the glass gets black. All radiators have vents - bad angles on my part.

@Jamie Hall Can you recommend any one in the Boston area? Rather not turn to YELP or anything like that. I will drop the pressure below two.

@BobC lifting the radiator makes sense, I had it up another 1/2 inch at one point. I think that will help with a bigger vent.

I appreciate the help here.