Direction Needed - Cold third floor

DaveT

My house is built in 1906 and we reside in Winnipeg MB. It's a two and a half storey, 2700 sqft, including an extension that is approximately 450sqft. The extension is heated by baseboard heat, but has a steam pipe with fins in the crawlspace. The attic was recently reinsulated with sprayfoam and blown fiberglass. The walls have UFI which is probably not doing a great job anymore. The third floor has 2 radiators, second floor has 6.5, and the main has 6. The boiler is a Weil-McLain (sp?) and I assume it's sized correctly.

So the problem is that while the main floor is nice a cosy, the second floor is slightly cooler, and the third floor is cold (relatively, probably around 15 celcius). There are two radiators on the third floor, it's basically one finished room and they do get hot, but only if the system is running for a prolonged period.

I have a couple of suspicions of the cause but I thought I'd get some expert opinions. First suspect is the thermostat. Do you need a thermostat specifically designed for a steam heating system? In this scenario I suspect that the thermostat isn't turning the heat on long enough to feed the entire system. Heat is also leaking from the extension (baseboard heating) into the dining room where the thermostat is located.

Second suspect is the steam vents on the radiators. I'm not sure what I could change here but I was thinking that if I put home grown slave thermostats on the third floor and TRV's on the main floor rads then I could heat the second and third floors without affecting the main floor.

Third suspect is the boiler. Maybe it's not sized correctly. It's not the original boiler, in fact you can see that at some point it was a two pipe system and possibly water not steam. According to one non-steam contractor the rads support water or steam (seems crazy to me).

So where to start? What seems like the most likely cause?
Thanks,
Dave

FYI I'm ordering Dan's books but the site doesn't allow me to enter a Canadian address.

ChrisJ

Please post some pictures of the radiators, piping around the system and piping around the boiler.

There are plenty of two pipe steam systems as well as many steam systems such as mine that use radiators designed for both hot water or steam.

My first suspicion is venting but we need lots of pictures before anyone can diagnose the system from a forum. The more the better.

What vents are on the radiators? What main vents do you have?

Steamhead

I've seen some old gravity hot-water systems that were converted to Vapor (ultra-low-pressure 2-pipe steam). They work great if you set them up properly.

If the radiators have traps on the return connections, they should not have air vents. In this case, the air is vented from a central point in the basement.

Jamie Hall

I'll go even further -- from what you describe, it's pretty good odds that it is, fundamentally, a venting problem. The objective of the exercise being to get steam to all the radiators as close to the same time as possible.

Now what needs to be done to the venting... follow ChrisJ's suggestion and get us some pictures of things.

As to the thermostat -- it's possible there is a problem there, too. Some thermostats have a cycles per hour setting. For steam that should be set to 1 cycle per hour. It may not be. If you have the manual for the thermostat, check that to see how to find out and set that (if you don't have the manual, tell us what it is and we can probably help!). Other thermostats -- particularly older ones -- have what is called an anticipator setting, and it is possible that that is set incorrectly. Again -- manual or tell us what you have.

DaveT

Thanks for the quick response guys. Photos attached.

So I believe Steam head is right, I'm not aware of a main vent.

I'll describe the piping in the basement since I couldn't fit it into a picture that made sense. From the boiler two large pipes merge into a single and then go up to the ceiling where they run around the perimeter of the basement. Smaller pipes run off of the main and feed each radiator. When we moved in there was no insulation on the pipes and the basement was very warm, so I insulated them.

Steamhead

If that's the end of the main at the upper left in the pic 20150901_205203, that's where the main vent should be.

The reducing elbow at that location needs to be re-oriented. Because it's pointing to the left, it is allowing water to collect there. I'll bet you get banging there when the steam reaches it.

The reservoir is probably not needed. Right now it is acting as the main vent via the trap at the inlet, but the vent in that Hoffman trap is pretty slow. That system returned the water to the boiler by gravity when it was installed, and gravity still works today.

How long is the steam main, and what pipe size?

DaveT

We do get banging, minimal when we first moved in 5 years ago, but each season it's gotten slightly worse each season. I'd assumed because the houses here shift a lot depending on rain and snow amounts.

The main is 86' long, 2.5" pipe, see pic.

SWEI

Sure looks like 2" pipe to me (2-3/8" OD.)

Steamhead

Right. It's 2-inch on the inside and that's the measurement we use.

You need a lot of venting on this type of main so the steam fills the main first, before rising into any of the radiators. Start with three Gorton #2 vents at the end of the main. The #2 is the biggest air vent made today.

DaveT

Thanks guys I'll get that done and post the results once the weather cools off.

DuggieFresh5

I don't have a good enough eye to spot the header in those pictures (I only have eyes for 2-pipe steam!), but make sure those 3 Gorton # 2's are on a 3/4" pipe if they are all off of the same taping.

Steamhead has helped me in the past as well. I'm sure he knows better than I, but it occurs to me that with 3 stories on the house, it may be worth venting the riser before the first radiator in that 3rd floor room. I would see how the system works after properly venting the mains first though.

I am also a hands-on homeowner and found a lot of value in the book "The Lost Art of Steam Heating" by Dan Holohan. Gerry Gill and Steve Pajek published a nice guide, "Balancing Steam Systems" which I think you will find very relevant and for less than the cost of a vent, help you make good choices the first time instead of guessing.

If you are working with a non-steam contractor, you will definitely understand you system better than him by time you give these materials a read and utilize the forum. Good luck!

Fred

@Dave T , Just so you know, that Pigtail (looped pipe mounted on top of your Low Water Cut-off is not right. In order for the Pigtail to hold water and protect your gauges and Presssuretrol from steam, the loop must be down so that water/condensate is held in the actual loop. The way you have yours installed, there is probably water sitting in the bottom of the straight pipe and steam getting to the Pressuretrol/gauges. You need an upright pigtail and then branch off of that with your Pressuretrol and gauges or you need to install an elbow in the LWCO opening (where the pigtail is now installed) then remount the pigtail into the elbow so the bowl of the loop is down and will hold water, then remount your Pressuretrol and gauges.