Old National-U.S. Radiator residential boiler question

Donovan45840

My son bought an old house with a steam boiler system for heating. Despite having no instructions to work with, we have made it through two winters so far, with the help of the very few remaining local contractors who understand residential boilers. A photo of the plate on the boiler is attached for reference.

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I have been trying to locate an original manual (without success) for the boiler so that we can make sure that we are doing the correct maintenance to keep it running. We realize that it won't last forever, but my son wants to defer the big expense of a new heating system for as long as is safely possible. My limited research so far suggests that the unit was built in the 1960's.

Can anyone suggest a way to locate an operating manual for this? Any advice on how to take care of this system would be appreciated.

Thanks,

Dan (in Ohio)

Jamie Hall

One should remember that the boiler is the power unit for the heating system as a whole — so you have a steam heating system which happens to be powered by an older boiler. This is not a trivial distinction, as if and when that old boiler does develop intractable problems, and most do sooner or later, it is not a question of a new heating system but only of finding and installing a new boiler to power the system.

As to maintenance, we can guide you much better if you could take a picture of the entire boiler, so that we can see what controls it has on it. In general, though, steam systems take very little maintenance. You should have someone come yearly to check and adjust the burners on it and make sure you are getting your money's worth from the gas you are burning — that is not a do it yourself project. Otherwise, the main thing is making sure that the boiler has the corredt amount of water in it, and making sure that the control and safety devices are working as they should — and that is mostly do it yourself, but the picture or pictures of those controls will help us guide you.

ethicalpaul

Just to add to all the correct stuff that Jamie said, I'll say that you came to the right place. Welcome!

bburd

@Donovan45840 the required maintenance for steam boilers is fairly standard. The few variations have more to do with the type of burner and controls than with the boiler itself. There is no need to stress about not having a manual for that specific boiler. Please post photos as requested above, and we can guide you.

Donovan45840

Thanks for the feedback. As requested, I've posting photos of the system as it looks today for your collective comments / advice. Th uploaded photo below is a good overview, and the attached photos have more detail:

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Dan Donovan (Ohio)

Jamie Hall

Not surprisingly, the near boiler piping is not what one might want — but if it's working quietly, that's not a problem.

On the front of the boiler there is a black triangular affair connected to the water level sight glass. It has a valve with a yellow handle on it. The traingular affair is your low water cutoff safety, and that valve is the only routine maintenance you have to think about: it should be opened about once a week or so to flush gunk out of that container into the handy bucket. If the is running when you do that, the boiler should turn off. Then refill the water level up to about half way on the sight glass.

That's it. Steam is pretty simple.

You should, however pay attention to how much water — if any — you have to add from time to time to maintain the water level, other than that which you addid above. Ideally you wouldn't have to add any. In practice anything up to a couple of quarts a week is probably OK — but anything over that is a leak somewhere, and it should be tracked down and fixed.

mattmia2

What is that expansion tank for? Can you take a picture of the back? Is there a hot water heating loop off of it as well or is it also making domestic hot water?

109A_5

Hello @Donovan45840,

I have a National-U.S. (without "Radiator" in the name) Gas Boler. I believe it is about 10 years newer than yours and has a newer look to it. I'm glad to see yours is still going.

The only major maintence this boiler has needed since my family has owned the house is many decades ago the Gas Valve had to be replaced since the original Blowdown valve on the McDonnell Miller No. 67 Low Water Cut Off leaked on it and we ignored it until the Gas Valve failed.

The McDonnell Miller No. 67 has had the Blowdown valve replaced a few times.

The McDonnell Miller No. 67 has recently had the switch and float assembly removed to clean out the rust contaminated float chamber. Messy job but not really hard.

I believe the McDonnell Miller No. 67 is the original to this boiler. I believe the McDonnell Miller No. 67 on your boiler is newer since I think the newer ones have that sticker on the switch assembly cover.

The water sight glass has been replaced twice. Both gasket leak related, first one shattered upon disassembly, I still have the second one, the third is extra thick glass with Teflon gaskets, hopefully it will out last the boiler.

I think compaired to other systems the maintence cost has been very low.

Also I believe the original boiler failed prematurely due to a whole house water softener that was found disconected when we move in, just a theory.

Edit: I forgot, the pigtail had been cleaned out a few times, no big deal there, but it should be kept clear.

I have never found a manual for this boiler. Hopefully your luck is better.

I do wonder why there is an expansion tank on yours, I don't think that is needed.

mattmia2

Er, never mind, I foudn the pictures of the back. Don't let whoever put that auto water feeder on work on it agian, if they put that expansion tank on a steam system, they don't know what they are doing.

Chris_L

It looks like that boiler has an autofeeder. So in addition to the regular blowdown of the low water cutoff previously mentioned, the reading on the feeder should be monitored between blowdowns to check how much water is being used. (I can't tell if the expansion tank is part of that.)

At the end of the season, I'd remove the Pressuretrol and replace the pigtail with a brass one—or at least make sure the one on there is completely clear. (And while your are at it, make sure the wheel inside the Pressuretrol is turned down as far as it will go.)

TonKa

You may want to check if the pressure relief valve is actually rated for steam. Also, there does not appear to be an outlet pipe on the PRV.

Additionally, I do not see a pressure gauge.

mattmia2

I woudl repalce the 70 year old pressure releif vavle and make sure it is clear back to the boiler.

mattmia2

oops, replied to the wrong thread

Donovan45840

Thank you all for the comments and advice received so far. A few follow-up questions that I have:

1. I'd like to understand the comment about the near boiler piping not being what one might want...can you explain what is not ideal about it?
2. Regarding the expansion tank, a local service person who we had in said that we needed one. Will it cause any problems by leaving it in place?
3. I will add an outlet pipe to the relief valve after confirming that it's rated for steam.

Donovan45840

I forgot to respond to the comment about the lack of a pressure gauge. Referring to the boiler photo, the square object in the upper right part of the front panel is a non-working gauge. I had asked the service people to replace it, but they said that they could not find a like replacement. I'd like to find a gauge myself and install it if there is a location on the external piping that will give me the correct boiler pressure. Where would be the easiest location for this?

Also, I'm confused by the comment "So maybe someone has this hose down a drain and running constantly." Can someone expalin what that is referring to exactly?

Thanks

109A_5

Hello @Donovan45840,

I believe that Presure Relief Valve style does not require and is not made for additional piping. An additional Presure gauge could easily be added above the pigtail and below the pressuretrol (the little gray box).

Typical good 'Near Boiler piping' is much different than what you have there. You looking at pictures would help you the most.

mattmia2

That gauge probably works but the system shouldn't build enough pressure to move that gauge within its accurate range. Add a 0-3 or 0-5 psig gauge off a tee above the pigtail and below the presuretrol. Make sure the pigtail is clear.

109A_5

Hello @Donovan45840,

Look as some of the pictures in this post below. The old boiler on page 1 has two supply ports like yours. Typically they are conected together with a horizontal header so the steam travles in one direction then comes the two mains connected to the header then the drip into the equalizer to return any condensate back into to the boiler. This provides dry steam to the system. Since your boiler is old and large and the vertical risers to the mains are significantly above the waterline before they get to the mains, wet steam may not be an issue in your case. There are other pictures (good and bad) if you poke around the site.

https://forum.heatinghelp.com/discussion/189734/new-drop-header-disappearing-water

Donovan45840

I am returning to this discussion, and now that the heating season here has finally ended, we are working on the things that were pointed out as needing attention, starting with the relief valve pictured above. I believe that I've located a replacement, but I have a follow-up question:

Is this valve intended to simply vent straight up if the boiler over-pressures? I retired from the chemical process industry where the exhaust of all relief valves was piped to a safe location. One of you even commented that it should be piped that way, but it does not appear to be designed to allow this. Comments are welcome.

mattmia2

Modern relief valves have a tapping for a discharge pipe that gets piped to near the floor or some other location where the discharge is safe but visible.

JUGHNE

You want to remove that old relief valve using a back up wrench.

That 90 ell must be clear into the boiler with no blockage. Pour water into it to be sure.

Get a new 15 PSI relief valve rated for a minimum of 174 lbs per hour, as it says on the boiler nameplate.

Then pipe it with copper, down to within 6" of the floor.

Donovan45840

Thanks for the comment. If I can find a relief valve with a more current design and comparable specs, should it function properly with this old boiler?

Alternately, what if buy an exact replacement for the relief valve, but add a short section of pipe between the elbow and the new valve moving it up and further away from where a person might be? This seems safer, as long as it would not compromise the function of the relief valve. I could use an expert opinion on that...

JUGHNE

Put new valve in same place.

If you can solder copper, put a 3/4" male adaptor in the outlet, then short piece and 90 with drop to the floor.

If you point the outlet away from the boiler you might be able to unscrew the entire copper drop tube, without unsoldering, for inspection to be sure the boiler port remains clear.

If you cannot solder, then you could use "Sharkbite" fittings to do the job.....never tell anyone that I recommended those. I could be banned here.

In any case the drop pipe must have no fittings on the bottom end going to the floor.

Hopefully that old design is not available anywhere anymore.

Donovan45840

I have found an Apollo relief valve (photo attached) that is designed for steam service with specifications identical to the old valve currently on the boiler, AND it has an exit connection that will allow any steam being relieved to be pointed in a safe direction. I value the opinion of those with more experience than I, so please comment on the use of this valve as a replacement for the original one. Thanks

JUGHNE

That would be a good replacement. Good brand name and plenty of capacity.

109A_5

Hello @Donovan45840,

Back-ordered... https://www.supplyhouse.com/Apollo-Valves-13101B15-3-4-MNPT-x-Top-RVS13-410-LBS-HR-Low-Pressure-Steam-Safety-Relief-Valve-15-psi.

Personally, I would worry about other things, and spend the money and time there, if you want that boiler to last a bit longer where is all the water going ? The VXT, 459 Gallons ? Seems a bit much. How old is the VXT ? You would probably replace the Pressure Relief valve with a new boiler anyway.

What is your EDR ? Although uncommon, my EDR is greater than the Boiler Sq. Ft. My boiler pressure never goes above an inch or two of Water Column, I don't (and probably can't) shut off all my radiator valves, I don't paint the air valves closed, and my Pressuretroll works, and the pigtail is clear, M&M 67 is maintained and works, old boiler (may never hold 15 PSI now anyways), pressure greater than 15 PSI is the least of my worries.

Emergency shut off switch at the top of the basement stairs ?

JUGHNE

Donovan, so if you had excessive water use, you should check for a leaking boiler.

If you overfill the boiler up to where the riser pipes feel cold from the fresh water.
Then let it sit, even overnight, and check for water on the floor.
If water shows up you most likely have a hole in the cast iron above the water line and have been sending steam up the chimney.

I perform this test on any older boiler even if it shows minimal water use.
No use working on a dead horse.

Donovan45840

Thanks for the comments on water use by this boiler, but I may have unintentionally misled the group about the amount of water it is consuming. The digital readout on the photo did read "459" at the time of the photo, but as I understand it, the counter is displaying the number of refill cycles that have been made, not the actual gallons of water. To be honest, I'm not sure how to verify how much water is being consumed, but based on when we were filling it manually, I'd say the usage rate is closer to a few quarts per week during the cold months.

Donovan45840

Thanks also for the question about EDR, a term that I was not familiar with. I have now watched the video by Dan Holohan that explains E.D.R., which has increased my understanding of steam heating systems. As I noted previously, the integrated pressure gauge is either non-functional or the wrong range, so the actual boiler pressure in use is unknown to me.

109A_5

Hello @Donovan45840,

OK, be sure, even at 459 cycles that may be a lot of water (Gallons per cycle amount setting?) ! Anyway the instruction manual states Gallons. Its an orifice, and at average water pressure about a Gallon a minute, I believe. BTW if you ever need to replace the Boiler the EDR total should be known to install the correct size new boiler.

https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Hydrolevel-45-026-Install-Instructions.pdf

JUGHNE

The flooding/overfill test is free.

As noted, I do it on known to be good boilers almost every year.

109A_5

Donovan45840 said:

Thanks for the comments on water use by this boiler, but I may have unintentionally misled the group about the amount of water it is consuming. The digital readout on the photo did read "459" at the time of the photo, but as I understand it, the counter is displaying the number of refill cycles that have been made, not the actual gallons of water. To be honest, I'm not sure how to verify how much water is being consumed, but based on when we were filling it manually, I'd say the usage rate is closer to a few quarts per week during the cold months.

I guess I would wonder how it got up to 459, where is it now ? With 15 Gallons / Month (worst case in the chart) = 30.6 Months or maybe over 4 years of service. Was the VXT used to refill after a M&M 67 blowdown ?

If you drain the boiler down slowly (no false VXT starts if you use the M&M 67 blowdown valve) to where the M&M 67 normally commands the VXT to fill (at the VXT's current DIP switch fill setting). Then let it fill to the satisfaction of the VXT. Then with a calibrated bucket (Gallons or quarts if you like) drain it again slowly until the VXT starts to fill again. The fill amount is settable with the internal VXT DIP switches (see manual). Check this setting it should be close to the amount of water drained into the bucket.

If you use the drain valve down near the gas valve you may avoid inadvertently tripping the M&M 67 LWCO switch and drain the boiler down faster. M&M 67 LWCO is designed to trip the float switch when blown down, water can flow out faster than it can flow into it. Don't get the Gas valve wet.

109A_5

Donovan45840 said:

Thanks also for the question about EDR, a term that I was not familiar with. I have now watched the video by Dan Holohan that explains E.D.R., which has increased my understanding of steam heating systems. As I noted previously, the integrated pressure gauge is either non-functional or the wrong range, so the actual boiler pressure in use is unknown to me.

Lots of information out there for those who seek it.
You can add another gauge near the Pressuretroll pigtail, folks often use a low pressure gauge like 3 PSI or less. The 30 PSI gauge is per code. For Pressuretroll operation verification the 30 PSI gauge is almost useless. If your EDR is close to the Sq. Ft. rating of the Boiler the system may never build any pressure above a few inches of Water Column.