Not enough heat with new boiler set at low pressure.

jwtoys

Hi there;

  Our old Weil-McClain EG-50(175,000) boiler @30yrs old blew a seal between cores and was replaced with a Burnham IN5 (140,000)boiler.  The problem is that the new setup doesn't produce as much heat at the  radiators as the old boiler which ran at 6-7psi vs the new one set to run at 2psi with a setback of 1.5psi.  After replacing the old vents with a mix of Hoffmans, vari vents and maid o mists and also tweaking the radiator valves the balance between the 1st(hotter) and 2nd(colder) floors is better but still not even.  The 1st floor has new anderson windows and insulated walls, while the 2nd fl has old vinyl windows and uninsulated walls (future project).  I  am now boosting the heating upstairs by adding fans to 2 radiators to increase convection. The new system heats to 2psi and cuts out until pressure drops to .5psi and restarts(@10mins a cycle).  Any suggestions to boost output or am I stuck with running the heating periods longer to make up the slower heat up?    

nicholas bonham-carter

Main vents?

You didn't mention the condition of the main vents, which do all the venting work for the system, as opposed to the radiator vents which are sized for the radiators. If the mains are inadequate, then you have been paying for a lot of extra fuel to force the air out of constipated little vents, under high pressure (30%?).

Post some pictures of the main vents, and we can advise some replacements. Keep the pressure low, and make the system work as it did when new.--NBC

Jamie Hall

Sounds like

two unrelated problems.  First, as NBC says, your main venting needs to be checked.  If there is a big difference between when heat first appears at the first radiator and when it shows up at the last, that's a big part of your problem.  Get that fixed and then you can start adjusting the radiator venting -- but not before.



Second, you mention something about 10 minutes a cycle.  That's way too short for steam, and may indicate that your thermostat isn't set properly for steam heat.  If it's got a cycles per hour setting, make sure that that is set at 1 cycle per hour; most thermostats come from the store set at 6, which is wrong for steam.  If it's got an anticipator, try setting that so you get a longer heating cycle.  If the boiler doesn't run long enough, there's no way it can get heat to all the radiators before it quits.

nicholas bonham-carter

Tweeking the radiator valves

Those valves should be fully open, so that the condensate can drain out underneath the steam.

I think you will find when you get the main vents up to capacity, you will see how the system operated when it was new!--NBC

JohnNY

Yeah.

Vents.

Fizz

Does boiler matche edr?

You note your old boiler was rated at 175K of btu, and new one at 140K, which is significant.  Do you know if your new boiler was sized to your connected radiator edr? 

ChrisJ

Venting

I agree with others, you need to fix your venting problems before anything else.



Just to put things in perspective, 2 pounds isn't low pressure, My system will fill all of the radiators at 2 ounces or less and chances are yours can do the same with a little tuning.



If you post some pictures of the new boiler, your radiators and the vents it will help us. Please tell us the size and lengths of the steam mains as well.



How long does it typically take to get steam to the radiators after the boiler starts steaming?

jwtoys

Work in progress

Thanks for the fast responses and suggestions.   I'll replace the only main vent in the system with a good one(Hoffman 4A) this weekend and see if it helps.   The main vent  is on the return drop from the front of the house @ 35ft away from boiler with no vent at the back return drop which is @ 15ft from boiler.  There is a mid-house vertical riser that I vented on top in the attic with a Hoffman 41.   House is a semi-detached 2 story 2 family in Brooklyn,NY.  Are there specialty steam thermostats i should be using?  I'm using a 6 event a day/ 7 day electronic rite temp now

nicholas bonham-carter

Main vents

I don't have the venting information for all the makes on this computer, so I can't check those Hoffman capacities. You need not only new vents, but also of large capacity. I would put on a Gorton 2 at each location.--NBC

Steamhead

That Hoffman 4A is too small

at minimum I'd use two Gorton #1 or Hoffman 75 vents on the longer main, and on on the shorter main. 

Binnacle

second that

Gorton #2s !!







--update qualification



over 2psi #2s may leak and hiss,

but you want to go lower than 2psi.

12-16 ounces or lower is enough for

even large multi-unit dwellings