Steam system repair and new boiler leads to water spouts and short cycles

Helgu

Hi. On old single pipe system I recently had my wet returns and boiler replaced (same make/size). The plumber assures me the piping is correct and the boiler uses the same amount of water. Interestingly, new wet returns do not run under the floor. Instead they slope/precipitously drop and then come in boiler at same place as old ones. I don’t see any ‘Hartford Loop’. So no reservoir for water on way back to boiler. When heat put on, water jetted at pressure from radiators on floor above and also came out of radiators on two floors higher. Then boiler short cycled. Boiler rep came and said nothing wrong with boiler. Plumber says problem is water returning too slowly to boiler causing it to draw in more water from the filler. Now they are going to use thermal camera to look for blockages that might be preventing water from returning and so causing it to back up in steam pipes. They then plan to flush every line. I have heat now as they’ve turned off filler valve entirely. I’m looking for second opinions as it’s been weeks and buckled floors! Any advice welcome.

ethicalpaul

Send pictures, but I wouldn't worry about the Hartford Loop related to this issue.

They need to "skim" the boiler to remove the oils that are no doubt floating on your boiler water. These oils come from any new pipe that is installed, so skimming is required any time new pipe is added to a steam system. Don't let them charge you for some kind of flushing operation. This is not caused by water returning too slowly unless your contractor was well and truly incompetent.

What is happening is that the oils on the water are causing water to get "carried over" into your main and then right on up to your radiators. Also it may be that your near-boiler piping is sub-optimal but I can't tell that yet.

When you say the boiler short cycled, was that because the Low water cutoff saw a low water condition (due to all the water getting thrown into your mains likely) and shut down the boiler?

The boiler rep didn't mention skimming!??!

It's good that your wet returns are now on the floor surface instead of buried.

ethicalpaul

Here is what is likely happening. The contractor should have skimmed, and should have known he had to skim, and the manufacturer's rep should have also known.

https://www.youtube.com/watch?v=jvt8qxBaRJU

Fred

Need Pictures of the new returns and near Boiler piping. As @ethicalpaul suggests, the boiler may just need a skim. Water may be so unstable that the auto feed keeps adding water when the level drops and eventually the boiler is over filled. I assume you've had to drain water each time the boiler ran, until you turned to feeder off.

Jamie Hall

I'm a little concerned about your comment that the wet returns precipitously drop and come into the boiler. Are they, in fact well below the water level for their full length, to the very last farthest drip attached to them? That's really critical...

Helgu

Helgu

Hope the photos help. Will find diplomatic way to ask my plumber about skimming. Really appreciate the advice.

Helgu

Also returns: one pitches down gradually around two walls about 20 feet and then some length horizontal. The other comes around ceiling of two walls, enters above boiler and drops to meet the other as in pic. Are they now dry returns?

Jamie Hall

That they are -- and depending on how they are piped and what attaches to what, you may have a real problem. You never want to convert a wet return into a dry one. Ever. It can cause real havoc. I need a fairly complete sketch.

Helgu

So just FYI with the water refill valve turned off my system is working and not complaining. Heat is stable at 70 and at 72 degrees. No banging. No spouting. Very head scratching!!

neilc

am I seeing the header and equalizer piped down to the right side return,
and the system condensate returns piped into the left return ?
you said no hartford loop, correct?
what pressure is on the gage when she's hot and boiling, highest pressure ?