McDonnell miller 47-2 overfilling boiler

EdTheHeaterMan

Interested in the results from over night???

matt_mccracken123

Water level holding steady.

matt_mccracken123

@EdTheHeaterMan
Ed the fix works really well, obviously the problem was, as you suspected, excess water was being added to the system. The water level in the boiler went down as the steam went up the pipes and into the radiators, when the steam condensed and came back to the boiler it added to an already filled revivor.
Although the fix worked well, eventually I'd like to add a solenoid valve to the water feed, shutting the water off when the boiler runs and then keeping the valve closed for 5-10 minutes after the boiler shuts down. If you have any ideas on how to hook anything like that up, that would be great.
For now the fix works well and will get me through the rest of the heating season. The fix with the solenoid I'll probably tackle in the spring.

109A_5

Hello @matt_mccracken123,

matt_mccracken123 said:

Although the fix worked well, eventually I'd like to add a solenoid valve to the water feed, shutting the water off when the boiler runs and then keeping the valve closed for 5-10 minutes after the boiler shuts down.

Since @EdTheHeaterMan's timer proved the point, why not change the piping (in the off season) so the system drains the condensate back to the boiler correctly ? Water trapped (while steaming) in the system pipes is reducing the space for steam movement, not helping system efficiency any. The correct piping will probably out last solenoid valves, timers and relay type stuff. Any water hammer now ?

Your solenoid idea if actually needed also just encourages unneeded wear and tear on the LWCO water fill valve components.

EdTheHeaterMan

Agree with @109A_5 on this. The solenoid is already made for what you have. The model number is VXT-120 and it has several features that can reduce or even prevent overfilling. The feature I am thinking of is the time delay. You can delay the feed for up to 10 minutes. Since you have a #2 switch the feeder would be switching to the feed valve when the burner shuts off via the LWCO. When the burner shuts off, it would start the clock on the water feed valve.

If you set it for the maximum timing which is 10 minutes, then the burner would shut off and the valve timer start. If the condensate returns in 2 minutes, then the burner would start in two minutes and continue to steam. If it took 3 minutes then the burner would start in 3 minutes and start to steam. If it takes more than 10 minutes then the feed valve will open and feed water until it reaches cut on level. This is the recommended way to solve your problem, but it costs more than a sprinkler timer.

If you are inclined to repipe the near boiler piping I believe that @delcrossv had the best idea. This is what it might look like
Of course the white lines will be thicker pipes al you need to use your imagination. But getting rid of the copper and doing the return is according the the manufacturers instructions, can't hurt.

delcrossv

Come off the bottom of the cross with 3" for a foot, then reduce for your return.

matt_mccracken123

@109A_5
No there is no knocking, the system actually works pretty good, with the exception of the overfill problem, that seems to be remedied, for now.

EdTheHeaterMan

I think this piping problem should be fixed when the replacement boiler is installed many years from now. Just an opinion based on the IIABDFT principle.

As far as installing a solenoid on the water feed... same principal should be followed here.

Why spend over $200.00 when a part for less than $30.00 solved the problem

IIABDFI = If It Ain't Broke Don't Fix It

matt_mccracken123

@EdTheHeaterMan, you may be right.