New Mini tube installation

Mark N

Loss

Doesn't a wet base boiler also lose heat out the jacket?

ChrisJ

the system.

Enreynolds,  How has living with the system been so far?  Are you glad you went this route instead of hot water?  

SWEI

less loss

A wet base boiler loses heat due to the difference in temperature between its lower water jacket and the ambient air (say 200F to 50F) most of which is insulated.



An atmospheric boiler loses heat due to more of its flame being exposed to the ambient air (say 2,000F to 50F) very little of which is insulated.



Heat loss is proportional to ∆T.

ChrisJ

True

But heat goes up not out the sides therefore any heat produced by the flame should be traveling against and through the block anyway.

No?

SWEI

against the block

is still far hotter than if it was inside the water jacket.

BobC

More insulation

After my new Smith G8 was installed I pulled off the top sheet metal and put in 3-1/2" fiberglass insulation. I put some down into the sides for about 6" or so and that boiler cabinet is cooler now than it was before. Anything that can be done to help the boiler retain heat has to be a good thing.



I did this with the old Burnham v75 and it made a difference there as well. It makes the cellar cooler but I can always put on a coat if I'm going to be down there for a while.



Bob

Enreynolds

Living with the Mini-tube system

Chris: Thanks for asking.  We are definitely glad we went with the steam vs the hot water system.  I have moved from 1 cycle/hr to 2 cycle/hr, which has felt much more even, even though the thermostat never moves off of the 68F it is set for. I have found that I need to make some adjustments to the supply lines to two of the 2nd floor radiators that have extra long runs: the pressure drop is just too much in the 3/8" tubing.  So I am to add some larger supply piping and a crossover trap to shorten the runouts.  I am continuing to tweek and balance the system, as well as skim and clean the boiler.  All in all we are extremely happy.

Eric

Rod

Maximum Viable Length of 3/8 Tubing

Hi- Thanks for continuously updating us on your mini project. You mentioned that some of your 3/8 lines had too much of a pressure drop as they were too long. With a low pressure mini system, what do you feel the maximum length and EDR that a 3/8 tube will support?

- Rod

Enreynolds

Pressure drop

Rod: The pressure drop calculator I posted a link to above seems to be spot on.  I am running at a max of 1psi now.  This pressure works great with the radiators that have a 10 foot runout.  I cheated on the two that I am having trouble with, ending up with a 21 and 23 foot runout.  No joy on that.  Furnished my daughter with an extra blanket until I run the new piping.  Even so, her room is still never less than 2 degrees below the setpoint.  This is a great system. 

I just started a new job, so I have been spending a lot of time with that, and it has been pretty warm up here in Rochester, so the incentive has been minimal.  I plan to post some updates after I get all the radiators heating correctly and balanced.  Maybe  by the end of the weekend??

Eric

Dave in QCA

Fantastic!!!

Eric,  I have intended to reply for quite some time!  The work you have done on your minitube system is fantastic!  The modulating burner is great!  Gas on a Megasteam, also great!



If my building was not commercial apartments, I would have done some things differently and would have been more open to experimenting. 



Keep us posted as you experience winter weather.

Enreynolds

Just swiched to

three cycles per hour as a test.  I holding at least 5psi of vacuum between cycles at 2 cph, and thus I am starting to boil at a192F.  I of course sized the baseboards for 215F steam.  The visionpro 8000 NEVER moves from the setpoint of 68F, but I sense that there is a temp drop.  Not uncomfortable, but noticable.  Since the baseboards do not  get as warm as designed, they cool off much faster, so now the experiment to see if we can keep a more uniform temp.

As far as the dual fire on the Carlin:  The boiler is currently never firing outside of a vacuum at present.  Think that the highest I have seen since we have been down in the 30s has been 1.3psi vacuum.  I have a 0-16oz vaporstat handling the Hi/Lo firing, and never hit Lo fire.  I may try raising the firing rate to get up to temp faster, getting into positive pressure, and then settling back to low fire to sustain temp.

Burner just fired, steam at end of main in ~30 sec.  I love this system!!  Response of a hot air system with the comfort of a steam system.

It doesn't get any better than that. 

I am continuing to skim and clean the boiler to calm the waterline.  The two radiators that I had trouble with had not been steam cleaned, so dumped all their oil back into the boiler after I got it clean.  Such is the joy of experimenting.

Eric

ChrisJ

VisionPro

The Honeywell thermostats are intentionally designed not to show a temperature change even when there is one.  I have a thermometer mounted a foot from my VP8000 and I see about a 1 degree change yet the VP never moves from its set point. 

Dave in QCA

Vacuum

Eric, I am encouraged by your vacuum operation observations.  I hope that I will see results that are as good when I get my system project finished.

Enreynolds

vacuum levels

Dave:  I have used only solder joints on all copper-copper joints, and generous teflon tape and dope on all threaded joints to reduce air infiltration to the system, thus the extreme natural vacuum I am seeing.  I suspect that you may have your hands full tracking vacuum leaks on your system for a while, because of its age, but I think your goal is definitely achievable.

Eric