Long Story of Homeowner Working on a Weil-Mclain for Years

jr6306 · 2:58AM

About 2 years ago I bought an 80 year old house that came with a 2019 Weil-Mclain one pipe steam boiler and original radiators/piping. The boiler has no plate saying what exact model it is but eventually after taking some measurements and looking at manuals I found its an EG-45.

The first year with the house I knew nothing about steam boilers and everything was working fine besides random light hissing and banging so I just left it alone. I started looking into maintenance more and did some basic water draining / filling and making sure the auto fill works. Eventually I figured out the boiler has 2 pressuretrols, a Honeywell PA404 and a L4079, with both of them basically maxed out on pressure settings. The boiler was running to 7 psi, likely for years, then cut-in around 2 psi.

I made adjustments and got cut-off at just below 2 psi and cut-in right at 0 psi. Next I calculated needed EDR and came up with 240 while the EG-45 is 388. To combat being oversized I installed a big mouth main vent next to the older main vent and changed all the radiator vents over to Vari-Vents and have them all wide open. I doubt I could vent any faster but the system runs completely quiet with no banging or hissing. It takes about 30 minutes for the boiler to cycle at ~2 psi from cold then around 3 minutes to get down to 0 psi and re-fire. The radiators are all ripping hot across nearly the entire radiator (checked with thermal camera) by the time the boiler cycles the first time.

I've made some other changes like replacing radiator valves that were partially leaking and very old, cleaned both pigtails + sight glass and top/bottom valves, installed a 5psi gauge next to the 30psi gauge, set the L4079 down to 3psi, and insulated all of the main pipes since they were causing the semi-finished basement space to become extremely hot. I also installed a Honeywell T6 Pro Z-Wave so I can control the thermostat with Home Assistant.

I can't get the PA404 to go any lower than 2 psi without failing to cut back in. My plan is to install a pressure transducer connected to a Shelly Uni and use Home Assistant to shut the thermostat to off mode when it reaches 1 psi, then have a 15 minute timer start until it switches the thermostat back to heat mode which will refire the boiler if the thermostat is not satisfied. That will act as a way to keep boiler pressure down without spending $500 on a Vaporstat and give me some data on boiler pressure behavior. The PA404 and L4079 will stay in-place and act as safety shut-offs.

When the boiler is hot the water is filthy with suspended particles even after years of draining + filling. I have fully drained the boiler while ice cold and I drain around 2-3 gallons when the boiler is hot and get tons of black sediment. When the boiler is cold the water is fairly clear and the sight glass is fairly clear too.

A few questions that I have:
-Is a lot of suspended black sediment, black chips in the water, and dirty water normal, or is that from years of 7 psi tearing up the boiler, piping, and radiators guts? How much damage do you think that did to the system?

-Is running to 1psi then having a 15 minute "cool down" period a good idea or should it just cycle quickly from 0-1psi? With the transducer and Home Assistant I can easily customize it. How badly does that tear the ignition components up?

-Does anyone in NYC want to trade an EG-45 for a 35 😁, or just reduce the 45 to a 40 since everything but the manifold is the same. I can't find anyone who has any interest.

-I found a crack in one of the feet, is that a normal thing or is this a cause for concern? Photo below.

Would love to hear any feedback or comments. I didn't want a new hobby but this is kinda fun.

ethicalpaul · 4:29AM

7 psi didn't hurt anything. You are doing fine. Have you tried a little 8-way in your boiler? It will slow down the corrosion but it may also free up some scale/sediment which will result in dirtier water in the short term.

mattmia2 · 4:52AM

the dirt is from never flushing the dirt out. if you can add fittings to flush any wet returns that will helo get the muck out of there. the boiler you can make a wand with a piece of copper tubing with some holes drilled in the side that you can hook up to a hose and run through the bottom tappings of the boiler to flush the muck out of the bottom of the boiler. treatment can help loosen and flush that stuff out too as @ethicalpaul said but actual flushing will get more of it out. some air gets in the system every cycle so you will get some rust. raising the ph with the treatment will reduce that but only use like 1/4 what the bottle says.

the cracked foot isn't ideal but it isn't hurting anything

some just use a time delay module in line with the pressuretrol. dwyer makes some pressure switches that are less expensive than a vaporstat. you probably want to re-fire it while it is still boiling a little otherwise you start having time when you aren't moving any heat in to the system, it is just radiating in to the basement. no steam=no heat in to the system.

i don't think that is a mercury pressuretrol but if it is, it needs to be level side to side.

109A_5 · 8:33AM

You can use 'Shelly Uni and Home Assistant' but that seems like using a super computer as a wrist watch. Also 15 minutes seems like it may be too long, and the delay may need to change depending on the season and/or the outdoor temperature.

I would get an adjustable pressure sensor and run the system at the lowest pressure you can. I'd look into the Dwyer 1800 or 1900 series on eBay NOS or used. The Dwyer 1823-20 seems to have a nice range. My system heats the house just fine at under 0.072 PSIG (2 Inches of Water Column). Dwyer makes lots of fun stuff for low pressure like MAGNEHELIC and PHOTOHELIC series gages, the only down side is you may have to calibrate your Brain to use Inches of Water Column instead of PSI or Oz, 1 PSI = 27.7 Inches of Water Column.

I'd get a better low pressure gage, like a Dwyer Magnehelic 2030 Differential Pressure Gage 0-30 Inches of Water Column and do some experimentation. Personally I like the center zero gages so I can see the vacuum. But probably not a big deal.

Or you could build a water Manometer see Link "Manometer for measuring boiler pressure" Scroll down (there are other examples). 1 Oz = 1.72999 inches.

As for the delay timing, there is different versions of the ICM203 out there and other timers with more features. With some systems with Dampers it may be a bit fussy with the minimum current specification and may need a buffer relay. If it is wired in after the Damper it may minimize the wear and tear on the Damper. Especially if the optimum delay time ends up being only a few minutes.

One example circuit.

Link ("Natural Gas size of House Line")

mattmia2 · 5:10PM

Then the damper is a whole different problem. you sort of want it closed when the boiler isn't firing to stop heat from the boiler from going up the vent but at the same time they aren't all that well suited for the environment that they are in and wear out if you are opening and closing them constantly. Most likely the energy you save isn't worth the cost of replacing the damper more often.

Long Story of Homeowner Working on a Weil-Mclain for Years

Comments

Categories