Best way to order Slant Fin Intrepid in MA/Southern NH

vvzz2

Hi everyone,
So I kind of expected to replace old Weil Mclain 78 when I inspected my new house initially(given that the previous owner mentioned how his plumbing guy installed automated water feeder that "made all problems go away", and also from the general state of the system) However, I hoped that maybe it could last a few more years. But after adding main vents, vaporstat, replacing broken pressure gauge and seeing that the boiler is not building any pressure, it became obvious that the boiler is shot. Flooding it yesterday confirmed it. I have natural gas, EDR is 1298 sq. ft. so my plan(based on general wisdom here) is to go with a pair of Slant Fin Intrepids TR-50Hs with Carlin ez-gas burners. I'm still a few months away from starting work, so I'm wondering what's the best way to get them without oil burner. Hopefully somebody has a good contact/rep I can talk to? I'm not a licensed plumber in MA so that makes it a little more difficult.
Thanks in advance!

Steamhead

You'd probably have to go through a contractor. Ferguson carries these units.

But with that EDR amout, why not just go with a Weil-McLain 4-80 and Carlin gas burner?

vvzz2

Steamhead said:

You'd probably have to go through a contractor. Ferguson carries these units.

But with that EDR amout, why not just go with a Weil-McLain 4-80 and Carlin gas burner?

I like the idea of at least some modulation and with two boilers I can run them in lead/lag configuration so one shuts off once the system is filled with steam(seems like few people do it this way here). It doesn't seem that there are any gas power burners in that size range that can stage fire.

EBEBRATT-Ed

Two boilers is a lot more piping and has it's challenges to make it work right. It can be done it is not easy. If it was my house it would have one boiler correctly sized

EBEBRATT-Ed

In addition to Ferguson, Peabody Supply and Granite Group sell Slant Fin

vvzz2

> @EBEBRATT-Ed said:
> Two boilers is a lot more piping and has it's challenges to make it work right. It can be done it is not easy. If it was my house it would have one boiler correctly sized

Thank you! I was looking at Peabody supply as it close to my house. I’m aware of water line, low water complications but I’m confident I can overcome it. I believe it also might be cheaper to have 2 smaller residential boilers vs big commercial one. I’m also excited about more complicated setups as an engineer

BobC

One of our members did this several tears ago and after a few bumps along the way I remember it working out well for her. If you can examine that thread it would be a good primer.

Now If I could just remember her name - anyone?

Bob

KC_Jones

@vaporvac is who I think you are talking about.

https://forum.heatinghelp.com/profile/vaporvac

You can browse through her threads from her page.

EBEBRATT-Ed

Controlling the water level is an issue. I have seen some where they connected the boilers together below the water line. This is illegal. The reason is one boiler cracks and as a result you loose both boilers due to lack of water. If you do connect them you must have check valves or piped so a leak in one boiler must not drain the other.

Also, the idle boiler will act as a condenser and will fill up with condensed steam. To combat this the boilers need overflow traps or motorized valves in the steam supply.

It gets $$$$$ and is somewhat problematic.

If it was me it would have a boiler feed tank with a separate pump for each boiler. Keep the returns to each boiler separated and just connect the steam together. Pump controls on each boiler.$$$$$$

vvzz2

EBEBRATT-Ed said:

Controlling the water level is an issue. I have seen some where they connected the boilers together below the water line. This is illegal. The reason is one boiler cracks and as a result you loose both boilers due to lack of water. If you do connect them you must have check valves or piped so a leak in one boiler must not drain the other.

I believe multiple modular boilers can be connected below waterlines since they are considered "one boiler". Here's Slant-fins piping diagrams: https://www.slantfin.com/wp-content/uploads/2016/02/Caravan-Modular-Boiler-Gas-Steam-Application-Guide-1112.pdf

Also, for the sake of argument. Wouldn't multiple LWCOs shown there take care of possible loss of water?

EBEBRATT-Ed

@vvzz2

Your right. The older Hydrotherms and Slant Fin are all piped together with NO valves between the boilers . That makes it one boiler. No different that one boiler with multiple sections. Hydrotherm used to use 1 operating pressure control and 1 low water cutoff for the whole bank of boilers because it was considered 1 boiler don't know what Slant Fin does

In Slant Fin's install manual they say that a 1/16 psi difference in pressure between between two boilers will make a water level difference of 2".

Try making that work, it dosen't work. With modular you don't fire all the boilers at the same time. The idle boilers fill with condensate through the steam header from condensed steam.

The boiler that has higher pressure pushes down on the water level and forces the water into the other boilers and goes off on low water. no check valves and no Hartford loop.

@DanHolohan I think wrote about this in the Revised LAOSH pg 478

As far as low water cutoffs go Coal boilers didn't have them and that's when the rules were written cutoffs fail as we all know.

The object is to protect all boilers water leaving one boiler to rush into another boiler that is leaking is against code

BobC

@KC_Jones Your right it was @vaporvac - thanks for shaking the cobwebs off.

Bob

Keith M

Modular steam boilers work very nicely provided they are installed properly. This means following our instructions. proper piping ensures there is equal pressure on all the modules supplies and returns. We used to have a 5 module set up heating part of our warehouse and offices and the water levels were stable and equal with any or all modules firing. We replaced them with our CHS boilers in 2013. We have an oil fired steam modular application guide and if all goes as planned I am attaching it to this post.
Note, in accordance with CSD-1 all modules must have a low water cut-off. Then the "modular boiler" needs another lwco (covering all modules) and mr pressuretrol.
Thank you,
Keith Muhlmeister
Slant/Fin Corporation