Low Pressure Steam Boiler Codes

DCsteamheat

Hi all, I am the president of a coop in DC and we have a recently replaced (last 5 years) low pressure steam boiler for a 1-pipe heating system. The boiler services about 25 units in the building. We recently changed maintenance companies and the new company is recommending two additions to the boiler that I wanted a second opinion on.

The first is installation of a backflow prevention device on the water makeup line between the makeup feeder and where the line feeds into the boiler (through the condensate return). We already have a check valve in this location and I can't find where a backflow preventer is required by code. Any ideas on this?

The second proposal is for pigtails for each of our pressuretrol/gauges. I can see that this is best practice but we have no issues with these controls and the previous company said that the pipe from which these gauges read is sloped slightly so that is holds water and protects the gauges. Any thoughts you have on whether these are essential would be helpful.

Thanks!

KC_Jones

Pictures of the pressuretrol gauge setup would be helpful. There are setups that allow for not having the pigtails so you may have this and be just fine, but pictures would verify. I don't know DC codes at all with reference to the backflow so I can't comment on that. I have one on mine even though it isn't code where I am, it just makes good sense to me.

Abracadabra

Boiler water is not considered potable... therefore:

https://www.dcwater.com/cc/

as @KC_Jones said, pictures of the pressuretrol setup would help answer your other question.

DCsteamheat

Thanks KC and Abra! I have included pics of the pressuretrol setup below.

Re: DC Water, I have looked at this website but do not see any specific reference to heating boilers. I do understand that the boiler water is not potable but by this same reasoning, wouldn't we all need BFPD's on washing machines and dishwashers? Also, I do not see where DC (DCRA) calls for DC Water code compliance.

The only applicable information I have been able to find is this:
"1007.4 Public water system mechanical feed. Each boiler
shall be provided with a mechanical feed line supplied from a
reliable public water system. The feed line shall not connect
directly into any part of a boiler exposed to the direct radiant
heat from the heat source. It shall be connected to the equalizing
line between the boiler and the condensate return connection
and shall have a check valve in the line as close to the
boiler as possible."

From here: http://www.ecodes.biz/ecodes_support/free_resources/2013DistrictofColumbia/13Mechanical/PDFs/Chapter 10 - Boilers.pdf

Anyway, any additional information or resources on these issues would be greatly appreciated.

Thanks!

Jamie Hall

On the question of why not a backflow preventer on a washing machine or dishwasher (or toilet tank or... or...). Backflow prevention should be provided in the appliance or by the plumber, with either a backflow preventer or an air gap. It's often built in.

Abracadabra

You don't need pigtails. That bottom horizontal pipe is meant to hold water. The setup you have is fine. Typically I like to fill that bottom pipe with water manually.

Regarding the backflow, you can also contact the AHJ and see what they say. In my area backflow preventers are required.

KC_Jones

Agreed that setup is just fine. I would guess either the service company likes spending your money for nothing or (worse) they don't know what they are looking at. If it's the second I would be cautious about what they do with your steam system.

Steamhead

Abracadabra said:

You don't need pigtails. That bottom horizontal pipe is meant to hold water. The setup you have is fine. Typically I like to fill that bottom pipe with water manually.

Regarding the backflow, you can also contact the AHJ and see what they say. In my area backflow preventers are required.

The problem with that gauge/pressure control manifold is that if the pipe clogs, it will render all those units inoperable at once.

Mounting the manifold higher than the tapping on the boiler and providing an individual pigtail for each gauge or control insures that one plugged pigtail won't affect the others.

I do know that DC codes require all that piping to be brass, which doesn't clog as often as steel since it doesn't rust. But brass is known to clog, so why not play it safe?

Abracadabra

In 20+ years I've never encountered a plugged 3/4" manifold setup like the OP's picture. Every LGB I've installed is provided with nipples and fittings to create a pressuretrol/gauge setup like that. I have run into several plugged 1/4" pigtails, always black, never a brass, and never a plugged 3/4" pressure control and gauge manifold. That's not to say it could never happen, but the chances I believe are quite slim to non-existent.

WM and Peerless both recommend the type of manifold setup the OP shows. As such, that's how I would install them. Makes it a lot easier to clean it out too, without having to remove pigtails. Just remove a plug at either end and wash it out.

Steamhead

Abracadabra said:

In 20+ years I've never encountered a plugged 3/4" manifold setup like the OP's picture.

We have. That's why we like individual pigtails.

vaporvac

I have that set-up for my Vstats and vacuum gauge, running off of my header, but the pressuretrols and 0-30lb gauge are on the top of the boilers attached to individual pigtails. SF recommends the above for a header. I recall I had to angle it down slightly.
I realize I have back-up, but should I be worried about this set-up?

DCsteamheat

Thanks all! Very helpful. I feel comfortable with the pressuretrol setup based on comments. I also check the gauges frequently throughout the season to make sure that they are still working. So all considered, annual or biannual cleaning should keep this in good order.

Regarding he back flow, I see that some kind of built in system would be in place with a dishwasher or washing machine but that could be as simple as a check valve or, as you note, an air gap. In my understanding, a BFPD is a step more sophisticated and once installed then needs to be maintained and inspected annually. I think our building manager is planning to have an inspector from the insurance company inspect it but I would imagine they would want any bell and whistle that would limit the insurance company's exposure.

vaporvac

@Abracadabra , is that schematic for use on the header or on the boilers themselves? SF showed mine on the header only. I'm just curious what the different manu. recommend.

Abracadabra

vaporvac said:

@Abracadabra , is that schematic for use on the header or on the boilers themselves? SF showed mine on the header only. I'm just curious what the different manu. recommend.

Those are to be installed off a tapping on the boiler. The one on the left is for a weil mclain LGB and the one on the right is for a peerless 211. Those 2 manufacturers and models constitute about 90% of my installs.