Unbalanced heat

jumbee

Fellow forum members help is needed.

This is a recently (April) acquired 3 level brick rowhouse.  The boiler is a Weil McLain EG45 with a Gross Output of 125000 Btuh.  I've calculated the EDR of radiators (using Dan"s book as a guide) and come up with 420 sq ft.  Pressuretrol is set at .5 psi with 1 psi additive diff.  Boiler is at rear of house. From these calculations it seems that the boiler is undersized. Main to the front is vented with 4 Gorton #1's.  Main to the rear is not vented. 

Ran the heat Sunday and yesterday to test and this is what happened. The rads in the front of house take a very long time to get warm, not hot, approx 90 minutes. The third floor front room rad gets hot, first floor gets warm. The second floor rad inlet valve got warm but rad remained cold..  The rads in the rear of house all got hot and the rads in the middle slowly got warm.

Are the problems due to the undersized boiler or is there another issue that I need to look for?  If problem is due to undersized boiler is there a possible fix other than replacing the boiler?

Thanks and any help greatly appreciated.

SWEI

392 versus 420

Close enough that with proper venting and insulation you should probably be OK.  Got any photos of the near-boiler piping?

BobC

Single pipe?

Make sure the mains and radiator runouts all have adequate slope and make sure there aren't any dips that might allow water to pool in the pipes.If the boiler is piped so it produces nice dry steam and the piping in the basement is all insulated you should be able to make this work. The rating on the boiler assumes a 33% pickup factor, you have to reduce the pickup factor on the system so the steam will be available for the radiators.



Is this single pipe steam, if so what radiator vents are being used? Post pics of the boiler, it's piping, the mains in any area you think there might be an issue and a couple of representative radiators showing both ends. Also where are you located?



Bob

jumbee

Unbalanced Heat

SWEI:

I'll post pics of the near boiler piping shortly

BobC:

The basement is finished but I opened up the sheetrock in some parts to look at the piping and as far as I can tell none of the piping is insulated.

Rad vents are a mix of Maid o Mist (which I don't necessarily like) and Hoffman's.  House is in Brooklyn NY

Paul48

Vents

       It sounds like a bunch of failed vents, on first impression. Because the rads do get warm eventually, the valve is open. We've heard the same complaints with TRV's on systems that run for extended periods. The closed vent will eventually allow the rad to warm up, and of course, they are used where people don't want it.

     There may be many issues, but try replacing vents on a rad or 2 that only get warm.

jumbee

vents

Paul48:

The second floor rads all have new inlet valves and new Hoffman vents so I'm not quite sure it's a rad vent issue. See attached pic

BobC:

See pics of near boiler piping

SWEI:

So what you're saying is that the 392 of the boiler includes the pickup factor? The 420 I totalled is just for the rads and doesn't include the piping

Paul48

Pressure

Is the boiler cycling on pressure during all that time?

jumbee

Cycling on pressure

I don't understand what you mean by "cycling on pressure" but the boiler never shut off during that time as the thermostat temp hadn't been reached. Boiler was running for about 90 minutes to raise temp 4 degrees in the thermostat room. This room has one of the rads that struggled to get heat.

Paul48

Puzzle

Need the steam pros to weigh in, but that seems odd to me. Ninety minutes running, with steam not getting to a lot of radiators, and the boiler doesn't reach cut out pressure?

BobC

You need to use some of that pickup factor

The 392 sq ft of steam is the amount of steam available to feed the radiators (EDR). There is an additional amount of steam produced to handle the pickup of the steam pipes. You have to insulate the steam piping on the boiler and as much of the other piping in the basement so you can use that pickup factor for the radiators upstairs. Don't forget to make sure the slope on the piping is correct. make sure the main vents are all working and have someone check the firing rate on that boiler.



Make a list of the radiators you have, the EDR of each one, and the type of air vent on each one. I've used Maid O Mist vents for a few years and never had a problem with them, they sell one model that comes with 5 different orifices so you can adjust the speed of the venting. I would start by venting the radiators that get hot very slowly and tr slightly faster vents on ones that only get warm, and a faster vent on any that don't seem to heat.



Bob

ChrisJ

EG45

The EG45 is plenty big enough for that system as long as all piping is insulated and venting is done correctly.



I would use plenty of main venting, the more the better.

You may need much larger vents on the radiators that don't want to heat. I have Gorton Cs on a few while others have Gorton 4s to keep them from stealing steam.





Would it be possible for you to give us a drawing showing all of your radiators, their sizes and approximate piping? I've attached a drawing I created of my system and it comes in very handy whenever I want to make changes. I just noticed I need to update it as the "botched piping" has been de-botched.

jumbee

puzzle

Could the boiler be under firing or have a blocked section?  The previous owner had stated that as she said "the guts of the boiler had to be replaced".  I'm no expert but the boiler was running for about 90 mins, with a new pressuretrol set at .5 psi with 1 psi additive, and it never cycled.

Maybe a pro can chime in here

BobC

clock the meter

To see if the boiler is burning the right amount of gas you should clock the gas meter while the boiler (and nothing else) is running. Turn off the water heater and make sure no one is using the stove while you do this. This link will give you an idea about how to do it -



http://www.aprsupply.com/support/technical-support/checking-firing-rate-%28clocking-meter%29



by the way this site is being reconfigured overnight so I'd advise you print anything out you think you might need till the transition is complete.



Bob

Paul48

Circ

What is that circ for?

Abracadabra

Is boiler raising any pressure at all?

Throw a 0-16" W.C. gauge on there and see if you are getting any pressure at all.

jumbee

Circ

Do you mean the circulating pump?  Its supposed to run hot water around some slantfins in the basement. There's a separate thermostat in basement for the slantfin.  When I ran the steam i shut off the circulating pump

jumbee

W.C gauge

What's a W.C gauge? Is that some kind of pressure gauge?