McDonnell miller 47-2 overfilling boiler

matt_mccracken123

The oil company still exists, the gentleman that put that boiler in has passed away. I've since converted to gas, I haven't found a good steam guy at this point.

EdTheHeaterMan

So the SGO boiler has a gas power burner?

Now you need a good steam boiler man/woman/person with experience on Power burners and understands how to do wet radiators that are connected to steam boilers, that live (or at least work) near you. Do you have any other requests? LOL.

So where are you located?

matt_mccracken123

@EdTheHeaterMan

matt_mccracken123

@EdTheHeaterMan pictures with insulation removed. If I were to clean the wet return on this system, which pipes would that be?

EdTheHeaterMan

I do not see a return in this picture

This photo may have the hint of a return where the orange arrow is pointing.


Can I see a better photo of the front of the boiler from far enough back to see from floor to ceiling where all the pipes go, including the water feed pipes. 4 camera positions with view of boiler from floor to ceiling.


If there are no return pipes, then you may have a counter flow system which means the condensation returns to the boiler by way of the steam main. Depending on how the condensation is returned to the boiler will determine how you go about making it come back faster.

matt_mccracken123

@EdTheHeaterMan
I’m in western Massachusetts.
This morning I was able to sit with the boiler after the morning run. The water level was normal when the furnace shut off , within 5 minutes the water was at the top of the sight glass. I removed about 5 gallons of water.

matt_mccracken123

@EdTheHeaterMan

EdTheHeaterMan

I need someone else to look at these pictures. There is not return at all in any of these pictures. The only thing I can think of is that you have a counter flow system and all your condensation returns to the boiler from the main, back down the riser into the boiler's supply opening. The bit of 2" copper is a choke point with higher exit velocity steam, that may keep condensation from dripping back into the boiler thru the supply. I can't see how this even works. @DanHolohan or @Steamhead @STEAM DOCTOR or maybe @ethicalpaul can make video... but I am at a loss for how this system even works without a lot of banging.

109A_5

Hello @matt_mccracken123,

It is interesting that the M&M 47-2 valve flow appears to be in the opposite direction from the manual. And it looks like the the copper pipes were changed to accommodate that.

Top View


https://s3.amazonaws.com/s3.supplyhouse.com/manuals/1350993347279/84563_PROD_FILE.pdf

matt_mccracken123

@109A_5
Good catch, I found the valve on eBay, but the flow was reversed. I reversed the plumbing to accommodate it. After observing the operation of the M&M for the past week, it seems that the unit is operating correctly. The problem happens during the longest run the boiler has, first thing in the morning. Typically the boiler runs for about an hour and a half in the morning. The level starts off good, during the run the water level gets low (not enough to shut down the furnace) and the M&M adds water. After the furnace shuts down water starts to come back to the boiler, raising the water level up past the sight glass. All that happens within 5 minutes of shut down. I think if I stopped the flow of water to the M&M after the furnace starts then let the water flow again 10 minutes after the cycle ends it may solve the problem.

EdTheHeaterMan

This might be a better way to connect the boiler in order follow the manufacturer's specifications.

This is a diagram of a counterflow one pipe system where the condensate travels down the steam main in the opposite direction of the steam
looking at the illustration, you can see that the main must pitch at a rate of 1" per 10 feet for the system to work properly.

The more common one pipe system is this oneThis is what everybody assumes you have when you say that you have a one pipe steam. This is more common, and the pitch is only 1" per 20 feet.

Since you are having a problem with condensate return on long run times of 1-1/2 hours, I believe that the pitch on your main may have changed as the house settled. This could cause the flow of steam to push the condensate up the main ever so slightly. That could be why you get a large amount of water to return once the burner stops making steam and that steam force is no longer pushing the condensate in the wrong direction.

If this is actually what is happening, one of the ways you may be able to remedy this is to have a timer that will stop the burner for 5 minutes every 30 minutes. This will allow the condensate to return every 30 minutes. And the off cycle will have little effect on the actual room temperature because in 5 minutes those radiators will still be warm.

109A_5

Hello @matt_mccracken123,

matt_mccracken123 said:

@109A_5
Good catch, I found the valve on eBay, but the flow was reversed. I reversed the plumbing to accommodate it.

I would think spinning the new eBay valve 180 degrees would have put it in the correct or at least the same orientation as the original, however I was not there.

If the steam part of the system is not counter flow, maybe the returns are co-joined with the return for the hot water loop. You need to take a good look at all the piping and maybe use a level on the main piping.

Does the hot water loop function well ?

Seem like there is some dead-ended abandoned stuff going on there also.

EdTheHeaterMan

If you are interested in using the cycle timer approach, I believe you can use something like this to get what you need. Timer on eBay

If interested I could draw you a wiring diagram

matt_mccracken123

@EdTheHeaterMan
Thank you, yes I’d be interested in the cycle timer approach, a wiring diagram would be great.
Would that be used to power a solenoid valve for the water feed?
By the way, thank you for all your help.

EdTheHeaterMan

This all makes sense now. You must have a counter flow design. All those other low to the floor pipes are too small for the original Return piping. And if they are, they are not connected properly.

Based on your description of your problem happening only on a long run time cycle, this is the best way to solve the problem. Unless there is another reasonable priced control that can be hardwired. First you can install a 120 VAC outlet powered by the Limit line from the boiler just before the 4 pin plug to the burner. Just mount a utility box on the side of the boiler where the switch plate is located. then wire the outlet with the Black wire removed from the 4 pin plug to the burner. connect a ground and common in order to power the timer. Then take a male end of an extension cord (2 or 3 prong is fine) and connect the black wire from the cord to the black wire on the 4 pin plug to the burner. Then cap off the white wire with a wire nut. If you used a 3 prong you can just connect the green to the grounding screw inside the box or cap it off.

Then plug in the cord to the timer.



Set the timer for 30 minutes on and 5 minutes off. If the call for heat ever exceeds 30 minutes, there will be a 5 minute rest to allow the condensate to return to the boiler. Even if your system is not a counter flow and the small 3/4" pipes are the return, this timer will solve your problem.

I also found that timer on Amazon and other sites. Seems it is a big hit for grow houses.
Timer on other site

I added the wiring diagram file below so you can zoom in for details

EdTheHeaterMan

matt_mccracken123 said:

@EdTheHeaterMan
Thank you, yes I’d be interested in the cycle timer approach, a wiring diagram would be great.
Would that be used to power a solenoid valve for the water feed?
By the way, thank you for all your help.

This will not control your water feed. It will stop the burner for 5 minutes, so the condensate can return normally, then the burner will run for 30 minutes as long as there is a call for heat. You will set the timer up for 24 hour operation. Even if the thermostat is not calling for heat, the timer will continue to cycle power to the burner.

You will only notice it when there is a LOOONG call for heat. Otherwise it will turn on and off the burner power even if the burner is off by the thermostat. (if that makes sense) Think of it like having 2 switches that operate the burner, the timer and the thermostat. They both need to be on for the burner to run. If the timer happens to be in the 5 minute off portion of the day (which will happen about 46 times a day) when the thermostat calls for heat, then the burner will not start until the timer re-engages the power to the burner. So there may be a delay or even a short cycle once in a while with this inexpensive setup. But you will no longer have the overfilling problem that happens on those long cycles.

delcrossv

Easiest would be to replace that top T going out to the two mains with a cross and feed the steam from the top with the bottom of the cross (present steam feed) connecting to the wet return. There's a convenient flange there.

The whole set up is rather amazing.

Sylvain

Maybe I am wrong but it seems the safety valve is plugged and there is a valve which would disallow its functionning if it wasn't already plugged.

delcrossv said:

The whole set up is rather amazing.

EDIT
It seems the safety valve is at the rear of the boiler.
What is the capped valve above the boiler for?

Sylvain

good reading about hot water loop:
https://heatinghelp.com/systems-help-center/how-to-run-a-hot-water-zone-off-a-steam-boiler/

Are you sure you didn't allow air to enter the water loop?
For instance by opening the valve with the hose going to the buckett without shuting the hot water loop ball valves [the one between the hot water return and that purge valve and the one at the back of the boiler going to the circulator].

If needed, while filing/purging again the hot water loop, you of course must isolate it from the boiler by closing the relevant ball valves (I have counted at least 3 on your piping pictures).

Now i am not sure if some air in the water loop would induce the problem.

EdTheHeaterMan

@Sylvain said: It seems the safety valve is at the rear of the boiler.
What is the capped valve above the boiler for?

I believe that is the supply for a wet radiator loop that was abandoned, The return is also capped off with the circulator pump still connected in front of the boiler.

I agree with @delcrossv. the whole thing is pretty amazing if it works without all the noise that would happen if I installed it that way LOL.

matt_mccracken123

@EdTheHeaterMan
I just bought the timer online, it will be here later this week. I'll let you know how I make out. Thanks again.

matt_mccracken123

@Sylvain
Good point about the hot water loop. Should the valve for the loop be closed when purging the excess water from the boiler?

matt_mccracken123

@109A_5
Yes the hot water loop seems to work well. The room that uses the hot water has is own thermostat but was not set up as a separate zone, so if you call for heat the circulator would run but not the furnace. I installed a programmable thermocouple to monitor the temperature of the pipe at the beginning of the loop, if the pipe temp is below 120 degrees the power is cut to the circulator, over 120 degrees and the circulator will run.

TwoTones

You could install an aqua stat to maintain a minimum boiler temp to run the hot water loop as its own zone, something you would only  want to have active during the heating season.  Your solution is more energy efficient as long as you are comfortable in the room most of the time… 

matt_mccracken123

@TwoTones
Actually the system I installed does ok, and it was pretty inexpensive. As long as the water temp in the pipe is above 120 the pump will run. Before I put that in, someone would turn up the heat and pump cold water into the room like A/C in the wintertime. LOL counter productive.

EdTheHeaterMan

TwoTones said:

You could install an aqua stat to maintain a minimum boiler temp to run the hot water loop as its own zone, something you would only  want to have active during the heating season.  Your solution is more energy efficient as long as you are comfortable in the room most of the time… 

^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
This would be wasteful.

You would want a relay and a High limit set to 165° so the water will get hot without making steam. The relay would operate the circulator pump and the burner thru the 165° limit.

As it is set up now, the burner only operates when the main thermostat calls for steam. So the water radiators will get heat only if there is a call for heat in the main zone. As long as this is acceptable, then no changes are needed. If however the wet radiator room is occasionally to cold, then adding the burner with a 165° High limit will allow the burner to operate for that zone without making steam.

matt_mccracken123

@EdTheHeaterMan
Maybe I’ll give that a try at some point. It would be nice to be able to call for heat from that room, without having to do the steam.

EdTheHeaterMan

What kind of thermostat do you currently have?
What is the wet radiator thermostat turning on to make that zone heat? Is it a line voltage thermostat connected to the line voltage that operates the circulator?
120 VAC L1 > thermostat > reverse aquastat 120° > pump motor > back to Neutral

OR

Is it a 24 VAC thermostat to a relay, then the relay operates the circ motor thru the reverse aquastat 120°?

Sylvain

matt_mccracken123 said:

@Sylvain
Good point about the hot water loop. Should the valve for the loop be closed when purging the excess water from the boiler?

Theoretically, not as long as the boiler water level is high enough to ensure an air seal at the bottom of the start and return of the loop.
Altough, as a precaution, I would close the valve near "the faucet with the hose going to the bucket" if it is the faucet you use for purging excess water.
If you purge the excess water by flushing the MCDonnell Miller there shouldn't be any loop problem.

matt_mccracken123

@EdTheHeaterMan
I just got the timer in yesterday, I'll be installing it over the weekend. I was just looking over your wiring diagram, so I'm taking power from the low water switch and the neutral from the service switch?
Is that correct?

EdTheHeaterMan

Yes
Then the outlet Line/Load side of the timer (Black wire) will feed the wire that connects to the Lim on the primary control.

matt_mccracken123

Great, thank you. I'll let you know how it does. I'm planning on installing it over the weekend.

matt_mccracken123

I’m a little confused, in your diagram you show a 4 pin connector (black wire) that the cord from the timer connects to, I’m not sure where that is.

matt_mccracken123

EdTheHeaterMan

Please excuse my assumption that you have an oil fired boiler. This is the first time I noticed that you have a Carlin Gas fired gun burner. Weil McLain does not sell that combination and I just saw the Carlin name on your burner and selected the Carlin oil burner diagram from the I/O manual.

There is a 4 pin plug connector factory installed from the front mounted switch box to the oil burner that can be disconnected in order to open the door and swing the burner away for maintenance and cleaning of the combustion chamber.

When the Gas burner was installed, someone moved the front mounted burner switch to the right side of your boiler as shown here.

But the wiring stays the same. The wire from the series of limits that ends with the LWCO, that goes to the burner control is what you need to interrupt. I can't be sure if the installer of the gas burner followed this diagram but if they did, then this will be what you want to print out and leave with the boiler manual for future reference.

Hope this makes things easy for your timer install.

matt_mccracken123

@EdTheHeaterMan
Thanks I will let you know, I'll probably look it over tonight and hook it up tomorrow.
Thank you for the clarification.

matt_mccracken123

@EdTheHeaterMan
I wired the timer switch this morning, the boiler is running, now we’ll see if it will keep the system from overfilling.

matt_mccracken123

EdTheHeaterMan

Nice. The photo is a little blurry... Did you set the time on to 25? and the time off to 5?

Other question... the photocell for day and night operation... is that able to be disabled to operate always?

matt_mccracken123

I actually set it for 15 on and 5 off. Yes I disabled day night operation. I’m monitoring the
Water now, I’ll let you know how it goes.