Overfill Shutoff Problem


  #1  
Old 12-15-05, 01:03 PM
Severian
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Overfill Shutoff Problem

I'll start out with main system components:

Ultra Gas Boiler - PEG150AS
McDonnell & Miller No. 67 Low Water Cut-off w/ No. 101-A Water Feeder
Honeywell 8214 Limit Control

This is the third heating season in my rental home. The house was built back around 1920. The first two seasons required a lot of water contol blow downs as the house had been vacant for some time prior to me moving in. During these years the problem would be sediment clogging, making the float stick "up" and the low water feed not kicking in to add water to the system as needed. This was manageable and just required weekly blow downs to maintain.

This season the radiators seemed to have been cleared of most of their sediment and the float is not sticking anymore. However, now the feeder will add too much water and shut down the gas control valve. Thermocouple is functioning / pilot stays lit, but the burners will not ignite until the water level is brought back down to operating range. This overfill happens about once a day or so.

Any ideas?

Thanks!
 
  #2  
Old 12-15-05, 05:11 PM
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Overfeeding

The 101A has a cartridge type valve assembly. This assembly is available as a service part and is supposedly easy to change.
 
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Old 12-15-05, 05:28 PM
Severian
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Thanks for the quick reply Grady.

The 101A seems to be functioning in regards to: I can hear the solenoid click and water flow, then shutoff. It's just doing this too frequently now days.

Should the 101A kick on when the No. 67 float reaches a certain point and then shut off when the float is lifted up again? Or does the 101A just add a 'timed burst' of water when 67 sends the solenoid signal? Because it seems to be doing the latter.
 
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Old 12-15-05, 05:57 PM
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I think the 67 has a long tubular float. There are two stages to the switch. The first (as the float drops) is the water feeder. The second stage is the low water cutoff. If mud gets in the bellows that the float uses as a hinge, it may not be able to go up enough to stop the feeder. The parts are all available and not difficult to install if you want to tackle the repair. There are no adjustments and not much chance of causing a bigger problem than you now have.

Ken
 
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Old 12-15-05, 06:06 PM
Severian
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Nice. It does have that long tubular float. So I could change out the float assembly without having to replace the whole unit? I'm not a 'strong' plumber... hehe.
 
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Old 12-15-05, 07:15 PM
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Here is the parts breakdown link.
http://www.mcdonnellmiller.com/pdf/M&M/Product/67.pdf
You should be able to find all of it easily. The diagram is probably all you will need to figure out how it comes apart. Mark the wires before you disconnect them. You don't need to pull them out of the connector, just off of the screw terminals. The end cover comes off with the wire and connector attached. Good luck.

Ken
 
  #7  
Old 12-16-05, 03:04 AM
Severian
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Thanks for the info guys. Nice link on the PDF KField, much appreciated. Looks like it could be an easy fix.

Sev
 
 

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