Something doesn't look right here......

The Steam Whisperer

EdTheHeaterMan

The ratings are that which show the AHRI net output (that used to be I=B=R Net Rating) is way low for a 315,000 input.

from Input to output is about a 77% efficiency rating loosing about 22% to 23% up the chimney.
From the 243,000 output to the Net rating is more than 25% for piping and pickup. I guess Weil McLain does not have a very efficient boiler, compared to industry standards of 15% for piping and pickup. Maybe you are not supposed to insulate the near boiler piping and steam mains to get those numbers!

Edit: I just checked Peerless and the numbers are slightly better but the Net to the gross output numbers are still near 25% for the piping and pickup. The numbers for water boiler of the same model is closer to 15%. I never looked at that before. I just looked at the Sq.Ft. to compare it to the existing radiation. This is interesting.

ethicalpaul

Industry standard is 15% pickup? I think that'd be great but around here a lot of people talk like 30% isn't enough.

But is that what didn't look like to @The Steam Whisperer ? Not sure

EBEBRATT-Ed

Steam pickup is 1.33.

Same ratings as Weil McLain web site.

Maybe that is without a vent damper LOL

The Steam Whisperer

What doesn't seem right is the relief valve rating required... Isn't it supposed to be the output of the boiler, not the input?

EdTheHeaterMan

I think it's the input. What if the chimney was plugged and the boiler operated at 100% efficiency for a short time with all the other safety devices in failure mode. Run away gas valve, or the like. Can't go wrong with the relief valve at the input rating.

But if you were that unlucky to have all the other safety devices fail, you would probably have a stuck relief valve too.

My grandmother's name was Murphy. Boy, did she have some strange laws.

ChrisJ

ethicalpaul said:

Industry standard is 15% pickup? I think that'd be great but around here a lot of people talk like 30% isn't enough.

But is that what didn't look like to @The Steam Whisperer ? Not sure

I think @The Steam Whisperer is one of the very few that probably views the whole pickup thing the same as I do. He's written about it as well and does fantastic work.

SteamingatMohawk

My HB Smith boiler nameplate says, Normal Input 165000, Heating Capacity 134000, Minimum Relief Valve Capacity 134 LB/HR. This boiler is over 20 years old,

The nameplate pictured has one of those QR code thingys on it, so it's got to be a lot newer.

Could the nameplate requirements have been changed?

EBEBRATT-Ed

The relief valve can always be larger than required. If it covers the input, it is safer

clammy

This is something that I ve come across on larger residential and light commercial steam boilers usually always steamers nearly close to forever it seems . Some manufactures are cheaper then other when it comes to the correct rated safety valve but if your curiosity is on the edge then start checking . . They seem to just throw the cheapest safety valve w the trim kits being The correctly rated one is not 60 bucks usually and now a days try 3 x . I know that many will just install what was given instead of getting and paying for the correct sized safety shame on you . Unfortunately a lot just use what’s given . I ve been on jobs where it’s been leaking since day one and it’s stated as normal after bring the ratings into the light and replacing w the correct safety no more dripping or slight lifting . This type of garbage has been standard by manafactures for years sticking it to the contractor or home owner sad that the money is so tight that the correct safety valve can’t be included by the manufacture. When I used to do larger boilers and such I always ordered a safety valve cause I knew they where not including the properly rated one . I know most never notice but this cheapness by manafactures has been goin on for 20 years ,I ve seen it many times first hand and usually the contractors refuse to get the correct one and I ve yet to ever see a inspector chk . At least another way to lose money on a job with out knowing until u check and then realize your out 100 bucks but that’s business and it seems everybody sticks it to some body some time and it seems it’s not only Weil doing it ,check on the light commercial steamers it’s always undersized . As for the ratings no flue damper and the larger residential boilers eff numbers are crap just standard some better then others .As my dad used to say big house big boiler big bills ,small house small boiler small bills small headaches I’ll always take the latter ,I’m out to impress no one except myself .lol
Peace and good luck clammy

ChrisJ

Are you allowed to use multiple pressure reliefs to equal the size required?

Or, is there ever a time multiple correctly sized reliefs are used so there's backup? Similar to multiple LWCOs etc.

I recently installed 2 more pressure reliefs in different areas less likely to see water, rust etc on our compressed air system in the shop after the pressure switch failed shut and I felt the one at the compressor wasn't enough for my liking.

clammy

Adding extra safeties to meet the expected rating is a bunch of hilly billy engineering at best ,anyone proceeding to do such is either a idiot ,cheap or both and a fool to boot . There are no substitutes for the correctly sized safety valve end of sentence . In my eyes if the manufacture is to cheap to include the correct safety maybe find a better manufactures or better yet don’t rely on them to get anything right and remember your on the hook not them . A fine example is most manafactures mim boiler header sizing a excellent example of getting it cheap and then wonder why duh . It’s the big race to a better bottom line ,a sad state for the consumer and the contractor either way some one pays and it’s not the boiler manufactures . Has anyone ever Called them out on it ,I have and it’s always the same excuse like for 20 years ,it should be ok and they send u the correct size one w a bill to boot .
At some point after a long time doing this trade u gotta just shake you head and walk away and let the rubes and hacks do there best and let the consumers suffer being they wanted cheap . Lol. The best part from all the lines I hear is where moving and then 2 years later your looking at the same mess ,the saddest part is it would have been way cheaper 2 years ago ,at this point in my life I send them else where and let them get screwed by some one else . Doesn’t put any $ in my pocket but it gives them some thing I cannot offer a cheap job .
Peace and good luck clammy

EBEBRATT-Ed

@ChrisJ

Yes, multiple safety valves are allowed to meet the rating of the boiler etc. On large low pressure steam boilers 4" is the largest valve commonly seen. Many larger low-pressure boilers come shipped from the factory with multiple valves installed. Never seen them installed as a backup.

As far as compressed air goes as long as there are no valves (obviously) between the compressor and the valve it shouldn't be an issue.

GGross

@clammy We don't get into much steam here so maybe it is something you mainly see in steam boilers for some reason. As a distributor my experience with included relief valves for boilers is almost entirely opposite, and if the boiler is over 199,000 btu input I always send a complete submittal form for the equipment that includes the items the manufacturer will include, such as the relief valve. While the manufacturers can be at fault, I implore you to contact your suppliers , If I send out that submittal form and the relief valve does not match, or is otherwise unacceptable, I am buying my customer a new one. There are industry partners that are and will be on your side and the first one to partner with is a good supplier that does not screw you around on ancillary materials.

Chris_L

SteamingatMohawk said:

My HB Smith boiler nameplate says, Normal Input 165000, Heating Capacity 134000, Minimum Relief Valve Capacity 134 LB/HR. This boiler is over 20 years old,

The nameplate pictured has one of those QR code thingys on it, so it's got to be a lot newer.

Could the nameplate requirements have been changed?

Similarly, the nameplate on my 30+ year old Burnham boiler says:
Input 105,000 BTU
DOE Heating Capacity 85,000 BTU
Minimum Relief Valve Capacity 85 lbs/hr

But the tag on the relief valve itself says it is rated for 400 lbs/hr. And when I did a quick search online for a 3/4" boiler relief valve for typical small residential boilers, I couldn't find one rated at less than 375 lbs/hr.

I'm a lot more concerned about the valve opening when it's needed than its capacity. (And yes, I do exercise it periodically.)

EBEBRATT-Ed

@Chris_L & @Steaming@Mohawk

There are only two things a relief valve or safety valve has to do.

Open at (or near) its rated pressure (withing a certain percentage)

The boiler should not be operated (normally) within 10% of the relief valve setting as this may cause the valve to weep and rust closed. So, a 15-psi boiler cannot be run above 15- 15x.10 or 13.5 psi

Relieve the number of BTUs (water or steam) that the boiler is capable of producing.

If you want to put a 4" relief valve on a boiler that only needs a 1" valve you can if you got a tapping big enough...........just a waste of money.

The relief valve does not have to match the boilers output............but at a minimum it cannot be rated lower than the boilers output but can exceed it and usually always does.

Valves on steam boilers are called "safety valves" On hot water they are known as "relief valves"