Bleeding 12 gallons and counting

heatseeker1

On Wed. Oct 17, 2018 I hired a company to convert my 2-pipe steam boiler to a Crown AWR105 hot water boiler. My house was built in 1925.

Before the conversion all 9 radiators were functional. I have 8 fin-style convector rads and one cast-iron stand-up rad. The radiators were all modified to accommodate the new heating unit. The diaphrams were removed from each radiator and bleeder valves were placed on each radiator. Along the way, the nut on one radiator was stripped so the radiator was replaced with a Burnham baseboard cast-iron radiator as opposed to utilizing a tap and re-thread kit.

Long story made short, I am no longer getting any heat out of the 2 radiators farthest from the boiler. It was suggested that I bleed those 2 again and see what happens. I have spent at least the last hour bleeding the one in the living room. The pressure at the boiler is currently at 30psi. Should I get my hopes up that this radiator, from which I just bleed 12 gallons will heat? Did I go overboard with the bleeding?

JUGHNE

How about pictures of the new boiler, circ pump, expansion tank and piping?
Did you change piping to the convectors or still using the old.

The 30 PSI on the boiler is close to opening the relief valve. I would lower it to less than 20 IIWM.

neilc

yeah, steam to HW conversion?
no one here will want to help with that, #smileyface.

can you post a diagram of the piping in the basement, and to the rads(2problem ones),
and maybe pictures of the piping to the 2 problem rads from below?

bleeding with circ on or off?
a picture of the boiler and its piping too.

heatseeker1

Please see the boiler and yes they used the existing pipes at the convectors.

JUGHNE

Can you see the other ends of the piping in the basement?
Often the end of the steam main is dripped (connected for draining) into the return pipe.
A picture of that would be good.

heatseeker1

I apologize that I am not on-site at the moment or else I'd send a picture of the end of the main; but it is connected for draining into the return. I guess my greatest concern now that I've drained 12 gallons through the radiator, how do I refill the system?

heatseeker1

Correction my pressure dial is reading 15psi when the system is at rest.

neilc

You might have to "break" or restrict that end of main drip to the old wet return.
Your heat may be bypassing those far radiators due to less restriction thru the return drip there.
If and when the system is drained down again,
add a ball valve, or compression isolation w/drain, between the scoop and tank.
You need to be able to isolate the tank and check it's pressure, which needs to match your cold fill pressure when isolated and drained.
If that 15 goes back up to 30 then you need to look at and service the tank.

JUGHNE

I hope some other Wallies will chime in on this.

If the old steam main (the 2" iron) is still connected to the return pipes (maybe 1 1/4" pipe), then starting at your new pump.
You push water thru the boiler into that 2", it goes thru the main and returns thru the 1 1/4". You have a loop around the house returning to the pump.

Some water flows up into some of the radiators and some return thru the small pipe. The reduction of the main to the return size creates some pressure differential that creates flow thru some of the convectors, but not all.

Just a thought/theory; I have been wrong but then I am also old .

BTY, Your auto fill valve should add water to maintain pressure.

heatseeker1

Hi Jughne, if my scenario matches your theory that some water flows up and some flows down, because the installers left the 2" main in place and attached the 1 1/4" pipe to that original pipe; is the only solution to change the 2" main down to a 1 1/4" pipe so that all the water goes up?

heatseeker1

Nelic, I understand fully what your are describing. Now I have to get these folk to come back.

neilc

get us a picture of that end anyways,
I only do this on the weekend, not a pro,
(but we're still right)
others here should jump in,
add a picture or 2.

JUGHNE

My guess would be that the crossover pipe between the steam main and return pipe be removed or a throttling valve installed between the two.
As long as all convector valves are open and flowing then the pressure of the main would push thru the heaters and return to the, well, actual previous return.

It seems common sense to have isolation valves in the supply and return pipes to be able to service any components at the boiler. These include the pump, pressure reducing valve, pressure relief valve, expansion tank, and air vent above the air separator. I don't even see a valve ahead of the reducing valve nor a backflow preventer.

Any work needed on any of these components will require the entire system to be drained and then air bleeding of all convectors is required.....time consuming.
Not knowing your local code requirements, perhaps none of this is required. But having gone thru the grief of changing just the pressure relief valve and refilling 2 floors of radiators the isolation valves is a no brainer.
Also the cold water connection could be done between the air separator and exp tank.

hot_rod

looks like the air purger is on the return?

JUGHNE

As is the pump etc. I don't know if this is code requirements or what we consider just good practice to pump away from the tank on the supply side of the boiler.

hot_rod

the circ is fine pumping into the boiler as long as it is pumping away from the tank. But air elimination is always best at the boiler supply

I’d wonder about return temperature also with large piping, water comtent and cast radiators?

nicholas bonham-carter

Just out of interest, what was the reason for the changeover to hot water heating in this system?—NBC

Solid_Fuel_Man

I'd be interested in if you see a change in gas usage over a few winters. Curiosity killed the.....

pecmsg

I hope you added a lot of insulation to that home because you just lost a lot of BTU output!

KC_Jones

Why is your installer not coming out to make the system they installed work?

I am reasonably positive that baseboard is not going to function as a convector, if your installer thought that was a good idea I would start questioning their knowledge base.

I would suggest your installer adds support to that gas line, having a pipe sticking out like that is a bad idea. Perhaps if they had run it as hard pipe into the appliance (like they should) it wouldn't look so bad. Also the unsupported electric....

I would have the installer come out and get it working, if they even have the ability to do so.

As was said hopefully the installer did all the proper calculations to design this system properly. I say that, but based on what I am seeing I am highly doubtful. If they get everything working hopefully when it's cold you don't come up short.

I am curious, why convert?

JUGHNE

Hopefully we hear from this homeowner as the temps drop.

The yellow AFUE on the new boiler looks to be 83% or so.
A new steam boiler would have about the same rating??

Plus the cost of the pump energy.

The lower temps of the water versus steam could be a concern for these emitters, IMO.

GBart

Just heating all that black pipe is going to cost, there's gallons and gallons in there, at the very least insulate all the piping you can get to, that could cause a huge temperature loss along the way, did they perform a heat calculation before this?

My argument with these conversions has always been if you aren't changing the piping forget it, it adds a lot of load.

I don't like the gas line hook up at all, I can't see the arrows on the circ or air purge, I don't see anything I like.

Gordy

Shame to go all that way with hard gas pipe to finish it off in csst. The best way to pipe the radiators is home run to a supply/return manifold. Get rid of the steam pipe. It is an extra load, BUT is also an excellent buffer. Many old gravity converted systems using the large diameter piping.

I have a feeling flow is bypassing the rads in question with heating issues. If you are not getting air when bleeding it’s not an air problem.

However proper bleeding is a good initial purging, then start at the farthest rads with circulator off, and work your way back to the closest emitters.

Jamie Hall

Well, that's a good -- and very expensive -- lesson in what not to do to a steam system. As has been implied, really the only way you will ever get that system to work is to rip out all the old piping and home run the feed and supply for each radiator to a manifold, with balancing valves. Then pipe the boiler properly (primary/secondary) and spend some time balancing it.

Good luck.

Or... you could convert it back to steam, at which point it would probably work just fine.