Moline steam system

Czakky82

Howdy, Ive been trying to sort my two pipe system since moving into this house and have hit a wall.
System overview: Moline system originally with 12 two pipe radiators with mostly new (non restricted) steam supply valves and all the return valves intact. The kicker is the house has a VENTED single pipe radiator added to an addition of the house. My research tells me that once the Moline proprietary air separator gives up the ghost it can be replaced with a main vent, which I don’t have. 

Here’s my problem: All the radiators in the second floor get hot real quick while three of the radiators on the first (edit) floor barely heat up at all unless the boiler cycles a few times.
Vaporstat set to 1.5lbs with a 12oz cut in.

Would adding a main vent help to get steam to the first floor?

thanks for any help

Jamie Hall

Without adequate venting on the dry returns... almost impossible to get it really right.

However, before you look at that, do you have crossover traps from the mains to the dry returns? If you do, are they working? if you do not, is there adequate venting on the mains (it would be newer)? You need that, too.

Then check that you are not getting any steam in the dry returns. Your problem on the second (?) floor sounds suspiciously as though one or more of those return traps is passing steam.

The ordinary non-restricting steam valves are OK, but they make the proper functioning of the return traps even more important.

The one one pipe radiator with a vent on it shouldn't be a problem, provided the runout to it is of adequate size and sloped properly.

Also, I'd be willing to be that you'll do better at lower pressure...

Czakky82

Thanks Jamie, I mistyped the problem is on the FIRST floor.

No venting on the dry returns, or the mains. There is a crossover trap from main to dry returns. 

Oh boy this opens up more questions.

How can I verify the crossover trap is working? The dry return stays cool to the touch.

For adding venting to the mains and dry returns can I just throw any proper sized vent? I see the Gorton #2 was suggested on another Moline system. 

Last question are the return traps rebuildable?

Jamie Hall

If the crossover trap is working, the pipe from the main to the trap will be nice and warm. In fact, maybe steam hot. But the pipe from the trap on to the return will be no more than nice and warm. If it's stuck closed, the pipe from the main to it will be no more than warm, as steam can't get there.

If your crossover trap isn't working, the guts can be replaced.

And then, if it is working, there is no need for vents on the mains -- the crossover traps do that. What is needed is vents or the dry returns. Most commonly all the dr returns will join together near the boiler, and that is where a good big vent should be located. If it's a "normal" size system one Gorton #2 is probably adequate -- but there's no harm to having two for bigger systems (except that they aren't all that cheap...).

The return traps should be rebuildable. Can you post a photo of one (and, while you're at it, a crossover trap)? Probably figure out what you need from that.

As I said before, I'm going to venture that the problem with your problem radiators is that a trap is leaking steam into the return in that area, and that keeps steam from getting to the radiators. However, also check and make sure that the pipes are all pitched properly.

Czakky82

Czakky82

Marked what I believe is the crossover trap. Main to trap is nice and warm, like you said almost steam hot.

If I was leaking steam would the trap be warm? They aren’t.

Im re-checking radiator pitch as well.

thanks again for the help I’m really enjoying learning these systems.
And yes the make up solenoid is quite loud

Steamhead

If it's the same one in the pic, the device you marked is an ejector, which uses steam pressure to create a slight vacuum in the dry return. This helps distribute steam. The ejector's outlet is connected to a long pipe that acts as a condenser in case any steam gets past the ejector. After the condensing pipe came an air trap which could hold vacuum, a great feature in the coal-fired days.

Czakky82

Yea it goes to a long loop that just goes back to the return.

so I guess I don’t have a crossover trap…

Gordo

@Czakky82 Have you by any chance checked YouTube for any information on Moline Systems?
Were those videos helpful in any way?

I would consider removing that MacDonald & Miller 101A. There are better (and cheaper) automatic water feeders on the market, such as Hydrolevel's VXT.

Czakky82

I never thought to check you tube for such a specific vapor system m. Will do. Thanks Gordo

Czakky82

Added a big old Gorton to the end of the mains and all radiators warmed up in minutes from cold, except my lone one pipe radiator…. Two steps forward one step back. 

Also it predictably used to kick on and off on pressure now it doesn’t even register on my low pressure gauge…

I’m satisfied for now. Thanks for the help

Steamhead

You'll want to repipe that radiator to make it work like a Moline.

Czakky82

Makes sense