Supply mains in two-pipe system are improperly pitched up going away from boiler. ???

LCAMES · April 28

I am a home inspector and just inspected an apartment house with steam heat. The system is reported by tenants to heat well, but every diagram i have seen for a two-pipe system shows the supply mains pitched down as they go away from the boiler. These pitch up. Any idea what gives here? Is this piped incorrectly? If so, what would be expected fallout?

STEAM DOCTOR · April 28

Pictures please. Not that uncommon to have the first few feet of the steam main pitched towards the boiler. Actually more common than not in my findings. There's also something called a counter flow steam system. Which is a bit of a different creature. Only slightly different

JUGHNE · April 28

Pictures would help, it could have been built that way correctly.

Steamhead · April 28

I've seen some Broomell and Tudor systems that were piped that way. Nothing wrong as long as they're properly sized. Remember, there is very little returning condensate in a two-pipe steam main.

pecmsg · April 28

How much Steam Experience do you have?

Intplm. · April 28

Probably a counterflow design as @STEAM DOCTOR mentions above.

Condensate at the bottom of the pipe flows back to the boiler, and steam moves in the opposite direction, "counter flow", away from the boiler, above the condensate, to the radiators in the same pipe.

Jamie Hall · April 28

The thing to look for is a drip quite near the boiler, so that the condensate can return to the wet return without getting in the way of the steam coming up out of the header. If it's got that, it's fine.

mattmia2 · April 28

Usually the system part of a steam system is ok if it hasn't been modified, it is usually at the boiler where the problems happen when the boiler gets replaced by someone that doesn't understand the system. It can have leaks, but usually the original installation was more or less correct.

LCAMES · April 28

My experience is limited to multiple steam heat classes in initial training and continuing education and inspecting the steam systems i encounter in my work. i have also read Dan Holohan's "We Got Steam Heat" multiple times I am by no means a steam expert or represent myself as one. Having access to experts like you is great!

I was not able to get a picture that clearly shows the supply mains running up hill from the boiler. But they surely do. I am providing a pic of the boiler piping arrangement. I do not see the end of main "drip" that you refer to. I would not fire this boiler for inspection because the sight glass was occluded and i could not confirm by it that it had adequate water. I did not want to damage the boiler.

The tenants say that getting heat is no problem and none of them complained about noises.

Thanks for your feedback!!

The red arrows (PIC 2) are two main supply runs that continue to run uphill. The blue is the combined condensate return pipe to the Hartford Loop. Each of the two condensate returns had an air vent (PIC 1) installed just above the common return shown.

I did not find an F&T Trap on this system (???)

Shouldn't pipe dope be used instead of Teflon tape?

ethicalpaul · April 28

It's got two "headers", the taller one is probably from a previous boiler installation.

There is no "header drip" or "equalizer" on the lower one and that makes a place where the condensate has to run back down against the steam.

But it may be fine. If condensate does get trapped there and pushed up to the higher "header" (imagine a percolator situation), that higher "header" has a drain to let the condensate return down to meet up with the wet return. I don't foresee any problem with steam quality from this technically incorrect installation. The boiler looks very small and the steam velocity isn't going to be very high so the condensate might flow back to the boiler without issue at all. We've all seen way worse.

If these pipes were insulated there would be less condensate to worry about also, at least when the pipes are still warm.

Teflon tape is fine.

Your return pipe into the boiler is looking a little crusty.

mattmia2 · April 28

Those main vents look way too small but i'm not an expert on identifying vents by sight.

As @ethicalpaul said, the header is wrong, it has no equalizer connection so there is no way for any water that gets in the header to exit, it will get carried in to the system by the steam.

From the steam trap that is either a crossover trap from the mains or a remoted emitter trap, I assume this is 2 pipe. If it is the returns need a way to vent.

ethicalpaul · April 28

Well that second "header" has a drain so I don't think water will go up into the main(s).

Jamie Hall · April 28

Someone was having fun…. actually you sort of have two headers there, and the upper one has the equalizer connection. Any condensate coming back through the mains — and, as has been said, there won't be much — will get over to that equalizer end and get back to the boiler.

A little unusual — but steam is sometimes oddly forgiving, and that arrangement should be fine.

STEAM DOCTOR · April 28

How old is that boiler

STEAM DOCTOR · April 28

img-9067b-jpg~2.jpg

I would think that the main on the left side would be problematic. I would think that they would both be problematic, but the left side should be worse. Does that have any benefits from the secondary header and header drain / equalizer. And never trust tenants. I find there are two types of tenants. One type will complain about anything and everything. The other type, more common amongst immigrant community, will never ever complain about anything, because they don't want to ruffle feathers and get people upset.

STEAM DOCTOR · April 28

I am assuming that you are doing this inspection for a potential buyer. If yes, I would at a minimum, stipulate that the current owner has to fix up the piping or allocate funds for that. In addition, what at the very least advice about age of boiler, whatever that may be, and the fact that you were not able to ascertain that it is firing safety. For that matter, the boiler that could have a hole on the top and nobody knows about it. Boiler just has an old look to it

LCAMES · April 29

Thanks for all of the comments. Trying to report what i can about system configuration, but found no service tags and have called for boiler and system evaluation and service by a qualified steam heat technician prior to closing. The boiler is a 2013 Utica. Yes, i did call out the corroded and apparently leaking return and called for insulation on the headers.

What about the unfound F&T Trap. Is one needed?

delcrossv · April 29

What about the unfound F&T Trap. Is one needed

No, crossover trap and drip into wet return covers it.

mattmia2 · April 29

looks like just a radiator trap.

is it one pipe or 2 pipe? it would be normal if it is where it belongs on 2 pipe.

that pipe above the header looks like part of the header from the previous boiler that wasn't removed.

mattmia2 · April 29

note that the insulation that is there is very likely an acm

Steamhead · April 29

https://forum.heatinghelp.com/discussion/comment/1853858#Comment_1853858

Those dry return vents are Hoffman #4A. Way too small.

@LCAMES , how long are the steam mains, what pipe size are they, and do they have vents at the ends?

HeatingHelp.com · April 29

Welcome to Heating Help @LCAMES! Have you read this book by @RayWohlfarth? It would be a great resource for you.

https://heatinghelp.com/store/detail/lessons-learned-a-guide-to-boilers-for-home-inspectors-valuable-tips-for-mechanical-room-inspections-volume-6/

EBEBRATT-Ed · April 29

Funny with that small boiler the installer used both tappings we usually don't see that. not sure if the lower header is 2" or 2 1/2".

if they had done the equalizer right it would be ok. Any condensate coming back to the upper header will be pushed toward the incorrect equalizer.

We have all seen much worse that worked.

ethicalpaul · April 29

I agree Ed, they almost got it right. Look, they even did the skim tapping correctly!

Supply mains in two-pipe system are improperly pitched up going away from boiler. ???

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