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Steam Condensate return problems

I am a 28 year hvac vet with my own business. I've worked on steam system for some time. I have a problem i need some advice on, here it goes

I recently (last week) had to do an emergency change out.I was supposed to receive the same Wiel McLain peg. Nat. Gas steam boiler. After receiving the new boiler I realized it was a different boiler, Wiel McLain LGB-5. I was sent CSD-1 controls which turned out to be a MM 150 main LWCO and a #63 manul reset LWCO. I have a Hoffman Watchdog WC-8-20B float operated condensate pump. The #150 has dual contacts, 1 set to shut down the burner and one set to operate a Return pump. The first night, the boiler shut off during the night. I came the next morning and had to remove water and reset the #63 to get the boiler to fire( I believe it steamed and shut off the manual resetting control and while it sat over night the condensate returned and filled the boiler). I watched the operation

for awhile and decided to increase the dwell period to 120 sec on the electronic fill valve. I watched the operation for a few hours andnit worked fine. Next morning unit was off on lwco reset. I have been baby sitting it for 3days now with the same outcome. In reading the install manual Wiel recommends a different style of condensate return pump to be operated by the #150 pump switch. The owner has no more money and I am running short on time. Is there a way to make this set up more efficient so that I don't have to babysit it anymore and the owner doesn't have tenants screamimng at him! Like wiring the float style condensate pump to the #150 pump switch and have it control the pump instead of the float and or have the float shut it down when water is not present in the pump so it doesn't run dry. Any help would be appreciated. Thanks.


  • kgbwheeler
    kgbwheeler Member Posts: 2
    Steam Condensate return problems

    Also the last few times, my water level was low and realized noticed that the way the boiler is cast the level of the #150 is only about 3" lower than the #150. I cannot understand why they gave me old style mechanical safeties instead of probe style??
  • Feed pump problems and angry tennants

    Try to make this a gravity return unless there is some good reason to use a feed pump and tank.

    An unstable waterline will cause this system to cut off on low water, and then overfill, so remove it and find out where the water has gone, or why it is so slow comming back.

    Check the pressure of the system and make sure it is not above 2 psi for basic function, or 2 ounces for comfort/ economy.

    When you ordered the replacement boiler, had you done an EDR survey of the radiators, to make sure you were not over-sizing the boiler?

    How are the main vents? For lower system pressures, those vents have to let out the air from the steam chest, and pipes with low resistance (back-pressure).--NBC
  • JStar
    JStar Member Posts: 2,752

    How is the pump piped? Is there a trap on the inlet? A water leg?
    EBEBRATT-Ed Member Posts: 15,353
    condensate pump

    I see no problem with using the mm 150 pump control to operate the pump as long as you use the float as a lwco for the pump, your basically using the condensate pump as a boiler feed pump.. I agree with operating the system on the lowest pressure possible, that should help to smooth things out. Also check that the new boiler is the correct size for the load... also the new boiler may need to be cleaned if the water level is unstable...I am assuming the near boiler piping is correct.

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