New Boiler / Increased Nozzle Size

TroubleinNY

Hi. I recently had a new boiler installed (Peerless ECT-03) and it was sized based on the sqft of steam equites for the number /sizes of rads. Without jumping into all of that info, let me just explain the issue. So after the installation, my balancing was thrown out of whack.  I was able to get all but one section of the house balanced.  The installer said he needed to increase the nozzle size to produce more steam to get it over to the colder side. I opted to install additional main vents on the cold main. We did this at the same time. That said, the whole house gets warm about the same time which is great. BUT, now I’m hearing some hissing coming from a couple of the rad shutoff valves. Could the larger nozzle be causing issues at the rad shut off valves? The rads with the issue are not off the original “cold” main. These rad shut offs were never an issue in the past and I find it hard to believe that it’s coincidental.  I appreciate any input. 

STEVEusaPA

"Out of whack" is almost always a venting issue.
The burner should be fired at what the manufacturer spec'd.

TroubleinNY

Thank you.  I think the venting issue corrected the cold main issue. If they oversized the nozzle, could that create too much steam or pressure that it would be too much for the rads? ie valves to spontaneously leak? 

EdTheHeaterMan

Your boiler can be fired at 0.75 GPH or 1.00 GPH. That said, if the .75 firing rate was increased to .85 or 1.00 then you are within the manufacturer's specifications. If however the boiler was fired at 1.00 GPH to start with, then increasing the firing rate is not proper. Caution should be taken when changing firing rate of the burner because a .85 GPH nozzle with 140 PSI pump pressure setting will yield 1.01 GPH firing rate, so don't just go by the nozzle rating.

Your boiler is rated at 288 sq.ft. at .75 firing rate and 379 at 1.00 GPH firing rate.

Jamie Hall

It's also possible that someone decided to increase the cutoff pressure setting -- which, of course, is quite the wrong thing to do, but a common enough "fix" among those who don't understand steam heat. I dare say there was no need to change the nozzle... and certainly no need to change the pressure.

What is the pressure control set at?

EdTheHeaterMan

Sorry I got distracted,

I was going to add that making 2 or more repairs at the same time makes it difficult determine what the actual fix was. My bet is the venting solved the problem, and you want to go back to the previous firing rate and see if the professional adjusted the pressure. If he did, go back to the previous pressure settings on the controls.

@Jamie Hall summed it up!

EBEBRATT-Ed

Yeah,

@TroubleinNY

You radiator valve probably always leaked a bit but was never noticed. You probably building steam pressure that you don't need.

calculate the EDR of your radiators x 240 this gives you the net output you need.

Example Lets say you have 300 sq feet of edr x 240btu/sq foot =72,000 btu/hr

72000 x 1.20 (efficiency) =86,400 x 1.33 (piping and pick up)=114,912 BTU fiting rate


114,912/140,000=.82 gallons/hour firing rate

tell you tech that's what you need and have him adjust and do a combustion test

Robert O'Brien

EBEBRATT-Ed said:

Yeah,

@TroubleinNY

You radiator valve probably always leaked a bit but was never noticed. You probably building steam pressure that you don't need.

calculate the EDR of your radiators x 240 this gives you the net output you need.

Example Lets say you have 300 sq feet of edr x 240btu/sq foot =72,000 btu/hr

72000 x 1.20 (efficiency) =86,400 x 1.33 (piping and pick up)=114,912 BTU fiting rate


114,912/140,000=.82 gallons/hour firing rate

tell you tech that's what you need and have him adjust and do a combustion test

Just keep an eye on the stack temps, that heat exchanger was designed for higher inputs and was derated by the manufacturer to meet ever rising DOE efficiency requirements. The attachment is a 2006 spec sheet on the exact same boiler showing a max input of 1.20GPH. Have seen condensation issues with more than one brand due to this.

TroubleinNY

Thank you all. The cut in is at .5 and out at 1. The rad shut off issue only started after the nozzle was changed and I I rested the main vents. I don’t think the main venting could affect the rads so I’m assuming the nozzle is producing more steam than is required. 

TroubleinNY

Ps the installer said the rad edr calculation is 418. 

EBEBRATT-Ed

418 edr I would fire it at 1.10gph

What size nozzle you need to achieve that depends on the oil pressure . Your tech has this information

Also, yes the main venting does affect the radiators.......venting is everything when it comes to steam

TroubleinNY

But would venting the mains faster cause what seems like increased pressure in the rads?

neilc

is your pigtail clear ?
what does the pressure gage say when the rads are spitting and misbehaving?