mcdonnell & miller pump control(jalcoplumb)

jalcoplumb_2

Twice in the past year I have had a malfunction of a M & M model 150s pump control. The unit was installed one year ago.

The customer called and told me he had water coming out of the steam vents on the first and second floor. (The water didn’t make it to the third yet).

He went into the basement and found the pump pumping non-stop. He shut the system down and drained it. Then turned it back on and the pump worked fine. I came out to check the system and it works fine. The float is free and works.

It worked for about three more months and had the same problem.

He blows the unit down once a week when the system is hot as per my instructions.

Does any one out there have a thought on this? Some kind of scale build-up that is removed by the flood? I have actuated the switch time and time again (by hand and through system cycling.) and cannot recreate the problem.

For now I am going to install a safety that will shut the system down if it floods.

Help!!

EBEBRATT_4

These controls are pretty reliable. If the control is mounted correctly and you have ruled out any scale or piping problems-could the lower pipe conection be restricted or partially plugged? I would check the wiring and wiring connections. Does the 150 run the pump directly--are there any relays or boiler feed valves installed? Sometimes with multiple boilers and end switch or relay may be sticking and keeping the pump on. Your solution to install a "high water control" may be the best way to avoid furthur calls--but it would still be nice to know what is going on.

Blackoakbob

bottom equalizer...

may be plugging up and not allowing the M&M control to see the rising waterline. I'd pull the crosstee cap or plug and check it. Blowing down the bowl of the control will keep the float chamber clean of barnacles but the lines may be filling up with crud. A good water treatment program will help if you find the piping getting dirty.
Best Regards,

jim bannister_2

mm 150 controller

Check the contacts on the 150. They have a tendency to carbon up and partially weld together, keeping the pump on continuously. The solution to this problem is to install a contactor between the 150 and the pump. Use a contactor instead of a switching relay because of the current rating of the draw.

ed wallace

mm pump controller

had a similiar situation last week turned out to be the feed tank float leaking by only way i found it was to turn cold water feed off to the tank and monitor water level in boiler and feed tank as water level in feed tank went up so did the boiler level

oil-2-4-6-gas

.

it may be a vacuum induced problem put a vacuum breaker on the piping or a check valve on the cross tee horizontal-or if you have a 220v coil on the contactor for the pump sometimes they get stuck

jalcoplumb_2

Water level is good .....

in the tank.

The pump is running non-stop.

jalcoplumb_2

Thank you...

for all the ideas.

Love this place,
Joe

ed wallace

mm controller

remove cover from the mm150 see if contacts are carboned up or welded together