Header advice, and other boiler replacement questions...

Steam_Jon

Hi all. I am a homeowner, and need a new steam/gas boiler. It's a 2-family residence with a 175K BTU boiler. I've gotten different opinions from different companies on some of the details, and wanted to get some objective opinions to settle the score.

1. Some say I need to re-pipe the header, others say it's piped correctly as is. I'd rather not pay extra for repiping the header if it's fine. Here are some photos. What do you think?
   
2. Do I need two low water cutoffs or just one? Some say one, some two.
   
3. Do I need two pressuretrols or just one? Some say one, some two.
   
4. Any objections to installing a Williamson? Seems to be a good bang for the buck option.
   

You guys are truly an awesome community, so thank you in advance!

nicholas bonham-carter

The photos are a little hard to see from being so close, but what little I can see leads me to advise a re pipe. This especially true for a economy side-outlet boiler. The manufacturers instructions will be specific about pipe sizes and layout.
remember that the new boiler should be sized to the system, and not necessarily to the old one.--NBC

JUGHNE

Did any contractors count and measure your radiators?
That would be an indication of a knowledgeable installer.
This would give you the size of boiler needed, they are often oversized.

You can download the installation manual for the boiler you are considering. There will be a piping diagram......which is the minimum requirements. If the outlet comes out of the sides then you can see how convoluted the piping would be trying to match up with existing.

Most here would probably recommend a repiping with 2 risers coming out of the boiler.

Fred

- Make sure you doa Radiator survey and total the EDR of all the radiators to properly size the boiler.
- The header is not piped correctly. It should be re-piped, at a minimum to the manufacturer's specifications.
- Depending on your local codes, one Low water cut-off and one Pressuretrol may suffice. Some municipalities require two. The primary and a back up, should the primary fail.
- Make sure you also have very good Main Venting on the system to move steam quickly and evenly, shorten heat cycle time and reduce fuel costs.

Fred

BTW, A Williamson boiler is a re-badged Weil McLain. Same boiler.

Steam_Jon

Fred said:

- Make sure you doa Radiator survey and total the EDR of all the radiators to properly size the boiler.

Thank you! One of the guys supposedly did an estimate and recommended a 175K boiler. I did my own estimate here and came up with 120K. So maybe the 175K makes sense to allow room for expansion? Is there any disadvantage to being oversized, besides the difference in boiler price?

Steam_Jon

JUGHNE said:

Did any contractors count and measure your radiators?
That would be an indication of a knowledgeable installer.
This would give you the size of boiler needed, they are often oversized.

I did my own estimate here, came up with 120K, and thought that 175K would be a good size to allow for expansion if needed.

JUGHNE said:

Most here would probably recommend a repiping with 2 risers coming out of the boiler.

The boiler I'm considering has a manual online here. Probably a silly question, but it seems as though it only accommodates one riser. Am I missing something?

Thanks!

Fred

Select the boiler most closely matches the 500 EDR you calculated. The boiler plate will have a 'Sq Ft" Steam Rating on it. That is what you want to match. That will give you a boiler that can satisfy 500 Sq. Ft. of connected radiator and also has another 33% extra output to handle the pick-up and piping requirements.
You don't want to over size the boiler. That leads to a boiler that will short cycle because the boiler produces more steam than the connected radiators can condense.
Spend any extra money on getting a Drop Header. That will give you a big return on your investment.
Stick with a boiler that says something close to 500 Sq. Ft. of steam output and do not add anything to that for piping and/or pick-up. That is already factored into the boiler.

Fred

@Steam_Jon said: The boiler I'm considering has a manual online here. Probably a silly question, but it seems as though it only accommodates one riser. Am I missing something?
Check with the local distributor. I am sure that boiler has two tappings, even though the manual shows just one (it shows the minimum installation). The boiler is a Weil McLain and it will have a second tapping with a plug in it. At 500 EDR, you need to use both tappings and risers into the header.

New England SteamWorks

The boiler you are considering does have 2 each 3" risers/tapings. And it is a fine boiler. If the installation is gas and in this size range, we use either your choice Weil McLain/GSA/Williamson, or Peerless. The gauges and controls are on opposite sides, so this sometimes makes the determination which we use.

You'd be safe with an EG-55 or GSA-200. But if it were us installing, we'd take a hard look at whether we could make the EG-50/GSA-175 work. Bigger is not better with steam.

You do need a new header. The steam supplies need to be piped into the header after the two risers, not one on each. Close, -but no cigar. And any contractor who didn't see this is not worth your time.

STEAM DOCTOR

Williamson has 2 3" tappings. Only one is listed in manual. When you run your numbers, remember that there is a difference between input and output. Also remember that there is a difference between gross output and net output(which factors in whats needed to heat piping). Also, one 3" riser is larger then 2 2" risers. Just saying

Jamie Hall

The manual does call for one 3 inch riser -- as @STEAM DOCTOR said, that's more capacity the two 2". Two three inch would work -- but may be overkill. However, in my humble opinion, it will work -- provided you make the header either a 3 inch drop header, or go to a 4 inch header.

Also, use the square foot rating to size the boiler -- not BTU.

Danny Scully

Your boiler is currently piped wrong so you can cross whatever contractors told you otherwise off the list. Where are you located?

STEAM DOCTOR

@Jamie Hall. Using square foot rating only works if you agree with the manufacture that 33% is the proper pickup factor. I am not taking a stand but as we know, this is a debatable point.

Jamie Hall

STEAM DOCTOR said:

@Jamie Hall. Using square foot rating only works if you agree with the manufacture that 33% is the proper pickup factor. I am not taking a stand but as we know, this is a debatable point.

Oh aye -- but it's not a bad place to start...

Steam_Jon

Danny Scully said:

Your boiler is currently piped wrong so you can cross whatever contractors told you otherwise off the list. Where are you located?

Understood. Thank you. Located in Brooklyn. The issue is that we don't have a big budget for this, and the estimates from the more established companies are coming in at $9K+. We have $6K. So I am trying to make it work with someone less expensive (who has installed a lot of boilers, and can sign off on the permit), and provide as much nuanced expertise from outside sources as possible. Not sure if that will net the best result, but the budget is what it is.

Steam_Jon

New England SteamWorks said:

The boiler you are considering does have 2 each 3" risers/tapings. And it is a fine boiler. If the installation is gas and in this size range, we use either your choice Weil McLain/GSA/Williamson, or Peerless. The gauges and controls are on opposite sides, so this sometimes makes the determination which we use.

Thank you for your advice! My current setup has all the controls on the left, so I've actually been wondering about whether my space would accommodate a reversed setup. Given one side that is more open (the right in my case) and the other being more tight (left), which boiler orientation would you go with?

New England SteamWorks said:

You'd be safe with an EG-55 or GSA-200. But if it were us installing, we'd take a hard look at whether we could make the EG-50/GSA-175 work. Bigger is not better with steam

Very insightful. Thank you. I was considering @Fred 's advice above ... "Stick with a boiler that says something close to 500 Sq. Ft. of steam output and do not add anything to that for piping and/or pick-up. That is already factored into the boiler." Based on that, I was looking at the GSA-125 or GSA-150, due to those being rated for 500 SqFt. in their brochure. But it sounds like you would go bigger @New England SteamWorks ?

Steam_Jon

STEAM DOCTOR said:

@Jamie Hall. Using square foot rating only works if you agree with the manufacture that 33% is the proper pickup factor. I am not taking a stand but as we know, this is a debatable point.

So @STEAM DOCTOR Based on a total EDR of 500 SqFt, and the Williamson options available here, I would have selected the GSA-125 or GSA-150, as they are both rated for 500. Would you go even higher than the 150?

New England SteamWorks

No, I wouldn’t go bigger. I am with Fred. Maybe I misread,but I thought the GSA200 was 500 and the 175 was at 450.

The Peerless 63 has controls on the right, sounds like the better option.

STEAM DOCTOR

@Steam_Jon. ASSUMING 500 s square feet, and assuming a pickup Factor of 33%, then you will need the GSA 200. The peerless has the controls on the right side but is considerably more expensive. The pressure relief valve is on the left side on the peerless. In addition, the Peerless comes with a cycle guard low water cutoff. Many if not all of us over here, are not fans of the cycle guard. In addition, the Peerless comes with a 120 volt low water cutoff. Not such a big deal initially, but most service technicians only carry 24 volt low water cut-offs on their trucks

nicholas bonham-carter

I would think the Peerless could be ordered in any configuration you want-maybe without any of the peripherals so you could choose your own LWCO, etc.--NBC

JUGHNE

So just to enrich the discussion; I just started to service steam system in another church.
It over 7500 sq feet of floor. Built in 1953. Maybe 30-40' to peak of cathedral ceiling.
It has 2689 connected EDR of 2 pipe convectors.

It has been heated at 65 degrees with no set back since 2002 with 2 Burnham IN8's. Max pressure in 1.75 PSI.
They are 245,000 btuh input each, labeled at 633 sq ft EDR.
Some how they heat the building. It is a little cool on the far end from the boiler but I think it still has the original end of main F&T traps. Possibly not venting air.

I know of the people that attend this church, if they were constantly cold some wheels would have been placed in motion to get more heat.......they just installed about 2 pallets of Italian Marble tile for new flooring.

So somehow this worked, by all the rules it should not have.
True, everyone has a coat on, the far end is cooler, system piping is all newly insulated, steam piping tunnel keeps floor and perimeter heated and no set back.

How is it working??

This much of a drastic cut back is certainly not recommend for a house but gives an indication that some under sizing can still heat the building....IMO.

the_donut

If it runs constantly and the heat loss is close to output btu, eventually the system will hit equilibrium. Cold radiators will draw more vacuum than hot, pressures will always stay low and slow. Probably works more like an old coal fired system than gas.

Danny Scully

@Steam_Jon, do any of the contractors offer financing? You really shouldn’t spend any money to have something done wrong. Wait and save if you can. In the end, you’ll end up spending more.

GBart

JUGHNE - "So somehow this worked, by all the rules it should not have.
True, everyone has a coat on, the far end is cooler, system piping is all newly insulated, steam piping tunnel keeps floor and perimeter heated and no set back.

How is it working??"

When you add people you add btu's so as church fills up once the doors are closed the load will drop. I think the figure is 450btu/hr per person at that level of activity.

JUGHNE

I did not intend to hijack the posting, rather point out the possibility of not using the standard pick up factor of 1.33.
There has been a fair discussion of pick up factors.

I hope to monitor the performance next winter of the example I submitted above, after more work in the steam tunnel this summer.

Steam_Jon

@Fred @STEAM DOCTOR @New England SteamWorks Something I hadn’t mentioned, regarding calculations, is that besides the rads there are approx 45’ of exposed risers/pipes running through the four floors, to the rads. Would those be covered by the standard manufacturer output recommendations? Or would that take me from your consensus of 150, to possibly a 175?

Also, I am now considering Burnham if that makes a difference.

Thanks guys.

KC_Jones

Getting 2 different sizes like that tells be immediately either someone isn't doing the calculations or someone is doing them wrong.

May I suggest double checking your numbers against this chart:
http://www.weil-mclain.com/sites/default/files/field-file/boiler-replacement-guide.pdf

The only reason I suggest that is the one you used assumes all tube radiators are the same and they actually aren't. The one I linked to give you depth dimensions as a double check to make sure you have selected the correct EDR.

I can't tell dimensions from pictures, but to my eye they don't look as big as what you selected.

Steam_Jon said:

Understood. Thank you. Located in Brooklyn. The issue is that we don't have a big budget for this, and the estimates from the more established companies are coming in at $9K+. We have $6K. So I am trying to make it work with someone less expensive (who has installed a lot of boilers, and can sign off on the permit), and provide as much nuanced expertise from outside sources as possible. Not sure if that will net the best result, but the budget is what it is.

I am just a homeowner, but this comment on some level scares me. Do you want it right or do you want it cheap? Winter is basically over so you have in my estimation 5-6 months to save up some more money and then do the replacement.

If it was me I would do that. Hiring a lesser contractor will, in my estimation, always cost more in the long run. What will it cost if they screw it up, you pay and then they won't fix it? Then you are back to going with the better contractor.

Also even if you find someone less expensive, after you give them a list of requirements (that better be in your contract) there is the very real possibility it will be just as expensive as the others. The difference being you will be paying to someone who may or may not know what they are doing, instead of someone who does know what they are doing.

Believe me I appreciate your position as any homeowner has been there. Scout around this website a little bit and read all the horror stories. So many coming here after the fact and having to spend much more money to fix the screw ups of a cheaper contractor.

You are lucky you came here first instead of after you got an improper install. You will have to live with this for a very long time.

Fred

@Steam_Jon , risers mains, run-outs are all factored into the boiler's "Pipe and Pick-up" What is built into the boiler is plenty for the piping. Don't add anything to the Sq. Ft. of steam and match it to your connected EDR, otherwise you will over size the boiler.

nicholas bonham-carter

You could contemplate installing the boiler yourself, and then have a licensed contractor finish/check the gas supply, and burner. Getting a 600 pound boiler into the basement would give you bragging rights at the office!! The drop header configuration makes the piping easier to fit, and you would have plenty of time to complete the job by next winter.—NBC

Steam_Jon

Hey again everyone. So, I am using my 500 SqFt EDR x 240 btu = 120K BTU Boiler. But when I look at the product literature for boilers, they don't seem to equate 500 Sqft with 120K BTU. Take for instance the Peerless boilers, where their 120K BTU unit is rated for 308 SqFt, whereas to meet 500 SqFt would require either their 175K or 206K units. So, I'm wondering whether to pick my unit based on the row with the closest match to 120K BTUs? Or whether to look at the row which is closest to my 500 SqFt. EDR?

Thanks!

Canucker

You don't size a steam boiler by your heatloss, you size it to your connected EDR.

Dan_NJ

Steam_Jon said:

Hey again everyone. So, I am using my 500 SqFt EDR x 240 btu = 120K BTU Boiler. But when I look at the product literature for boilers, they don't seem to equate 500 Sqft with 120K BTU. ...

I'm confused, your first post says existing unit is 175k BTU. Which is right in line with your 500 sq ft number.

Jamie Hall

Go by the EDR rating of the boiler. It's there for a reason. Other numbers might be gross input BTU, net output BTU, etc.

Fred

@Steam_Jon , Don't convert the EDR to BTU's. It is not necessary. Just find a boiler that says 500 SQ. Ft. of Steam output on the rating plate. That rating does not include a "hidden" 33% added BTU output to cover piping and pick-up.

If you insist on using BTU's then The Boiler's actual output is 500 EDR X 240 BTU/per EDR = 120,000 BTU + 33% piping and pick-up factor or another 40,000 BTU's for a total boiler size of 120,000 + 40,000 = 160,000 BTU. A lot of calculation just to get back to what the boiler manufacturers have already done you you when they state the "Sq. Ft.' number on the rating plate.

Steam_Jon

Gotcha. Thank you @Fred and @Jamie Hall !

Steam_Jon

Now the question is, do I round down or round up based on my house's 500 Sqft? Burnham has a 175K unit rated for 450 sqft, and a 210K unit rated for 542 sqft. Hmmm....

Dan_NJ

I'm no expert but it seems to me unless you have some plans to expand the living space significantly you could opt for the lower capacity 450 sq ft and at the same time insulate all the near boiler piping and get a pretty good result.

Steam_Jon

Fred said:

@Steam_Jon , Don't convert the EDR to BTU's. It is not necessary. Just find a boiler that says 500 SQ. Ft. of Steam output on the rating plate. That rating does not include a "hidden" 33% added BTU output to cover piping and pick-up.

If you insist on using BTU's then The Boiler's actual output is 500 EDR X 240 BTU/per EDR = 120,000 BTU + 33% piping and pick-up factor or another 40,000 BTU's for a total boiler size of 120,000 + 40,000 = 160,000 BTU. A lot of calculation just to get back to what the boiler manufacturers have already done you you when they state the "Sq. Ft.' number on the rating plate.

The issue @Fred is that it seems Burnham is using a pickup factor of 62%. If they rate their 175K unit at 450 SqFt, and their 210K unit at 542 SqFt, then they are assuming 389 BTU / Per SqFt. 389 is 62% higher than the standard/base of 240 BTU per SqFt. Unless I'm calculating this incorrectly, then I have to make a decision of whether to use their pickup factor, or my own?

GBart

Steam_Jon said:

Now the question is, do I round down or round up based on my house's 500 Sqft? Burnham has a 175K unit rated for 450 sqft, and a 210K unit rated for 542 sqft. Hmmm....

Never round down.

KC_Jones

175,000 input * 82.1% efficiency = 143,675 usable BTU's
143,675 / 1.33 (pickup factor) = 108,026 BTU's for system
108,026/240=450 sq ft EDR