|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Troubleshooting
and Maintaining Condensate Pumps
in Steam Heating Systems
Most
two-pipe steam heating systems employ the use of condensate pumps and receiver
tanks,
either the standard float-operated or boiler feed style, to collect the condensate
(water) returning
from the steam heating equipment. Once the returning condensate arrives in the
receiver tank,
these pumps send the accumulated water to either a boiler feed tank (most cases)
or directly back
to the boiler (in small steam heating systems).
Condensate
pumps, like anything else mechanical, will eventually break down.
Check-out the following troubleshooting tips. These should help you diagnose
the problem, and the corrective actions you can take to get that condensate
pump
again working efficiently.
TROUBLESHOOTING TIPS
When the pump will not start:
1.
The power supply may have been interrupted, or the optional switches on the
control panel
(you would have a control panel only if your pumps operated with 3 phase motors)
are in the
wrong position.
M
2.
The pump motor may have the incorrect voltage, or the starter coil may have
the incorrect
voltage rating.
M
3.
The overload relays and starters may have tripped "off" and need to
be reset.
M
4. The strainer on the inlet piping before the receiver may
be clogged. Please remove and
clean the screen. If the screen is too corroded, cracked or otherwise damaged
order a
new replacement screen.
When the pump runs continuously:
1. Steam traps within your system have failed "open:"
The steam racing through your
condensate return lines is heating-up the returning water to temperatures of
200° F. and more.
Standard condensate pumps cannot efficiently discharge condensate at these temperatures:
The impeller spins wildly as steam enters the pump, losing its ability to pump
the water.
Your pump is now cavitating -- You can hear the sound of "marbles"
rattling in your pump.
Steam may be venting from the air vent on top of the receiver tank.
You need to repair your steam traps as soon as possible.
2. If you incorrectly wire a 3-phase motor the pump will
run backwards -- You won't be pumping
anything. To correct this situation, interchange any two of the three motor
wires to obtain a
clockwise rotation of the impeller.
3. Perhaps the pump is not powerful enough to overcome the
boiler pressure and static head
pressure. Perhaps a change in the system caused the pumping requirements to
change.
Perhaps the pump as simply sized too "small."
4. Look for a bad check valve on the pump discharge piping.
Also, look for a check valve that
may have been installed backwards. Check the other valves on the pump discharge
piping --
You may have a globe (throttling) valve throttled too tightly.
| When
the condensate pump is noisy: 1. The pump may be discharging the condensate at "too high" a pressure! To reduce the discharge pressure find the globe valve, or other throttling valve, on the pump discharge piping. While the pump is running, listen for a "chattering" noise coming from the check valve. Next, turn down the handle on the throttling valve until the chattering noise goes away. Now, you should have the correct discharge pressure. 2. The pump may be cavitating due to steam entering the condensate return lines. Fix your steam traps. 3. The pump and motor assembly may have a bad starter coil that is chattering, or the pump impeller may be running backwards. |
 |
When the system is noisy:
1.
Banging and clanging in your steam piping is usually caused by water
hammer --
steam "imploding" into condensate. You have bad steam traps -- Repair
or replace.
Also, check for low-points in the condensate return lines that need (but don't
have) an
F&T trap to remove the accumulating condensate, and "sagging"
condensate return lines
that need to be replaced so they don't collect and hold condensate. Water collecting
and
"ponding" in these sagging lines cause nothing but problems.
2. Portions of the condensate return lines may be too corroded
with "gunk" on the inside to
allow for proper condensate return flowage back to the receiver tank.
 |
FREE
Steam Heating Repair & This
80-page guide to steam heating repair and maintenance is |
 |
FREE McDonell-Miller Boiler Controls Repair and Maintenance Guide A great reference manual for any building maintenance library. Loaded with the product and repair information you need to confidently maintain and repair your McDonnell-Miller boiler controls and flow switches. And
the best part? It's absolutely FREE! No cost for this 68-page repair and
maintenance guide -- Not even a mailing charge! |
