Multiquip MQD2H manual General Information, Application

GENERAL INFORMATION

APPLICATION

The MQD2H and MQD3H diaphragm pumps are designed to be used for de-watering applications.The suction and discharge ports on the MQD2H use a 2-inch diameter opening, which allows the pump to pump at rate of approximately 3,000 gallons/hour (gph) or 11,340 liters/hour (lph).The suction and discharge ports on the MQD3H use a 3-inch diameter opening, which allows the pump to pump at rate of approximately 5,400 gallons/hour (gph) or 20,456 liters/hour (lph).

Diaphragm pumps use a positive displacement design rather than centrifugal force to move water through the casing. This means the pump will deliver a specific amount of flow per stroke, revolution or cycle. These pumps are commonly referred to as mud hogs, mud hens and mud suckers.Their names reflect their popularity for use in applications where shallow depths and slurry water render centrifugal pumps ineffective.

Power Plant

These diaphragm pumps are powered by a 4.0 horsepower air cooled, 4-stroke, single cylinder HONDA GX120 gasoline engine that incorporates a low “Oil Alert Feature”.The drive shaft of the engine is coupled to an offset connecting rod that is coupled to a flexible diaphragm. The connecting rod alternately raises (expands) and lowers (contracts) the diaphragm at a rate of 60 cycles per minute at maximum engine RPM (2,750).

Oil Alert Feature

In the event of low oil or no oil, the HONDA GX120 engine has a built-in oil alarm engine shut-down feature. In the event the oil level is low the engine will automatically shut-down.

Suction Lift

This pump is intended to be used for dewatering applications and is capable of suction lifts up to 25 feet at sea level. For optimal suction lift performance keep the suction hose or line as short as possible. In general always place the pump as close to the water as possible.

Pump Support

The pump should always be placed on solid stationary ground in a level position.

NEVER place the pump on soft soil. The suction hose or pipe connection should always be checked for tightness and leaks. A small suction leak in the hose or fittings could prevent the pump from priming.

Elevation

Higher elevations will effect the performance of the pump. Due to less atmospheric pressure at higher altitudes, pumps DO NOT have the priming ability that they have at sea level. This is due to the “thinner air” or lack of oxygen at higher altitudes.

A general rule of thumb is that for every 1,000 feet of elevation above sea level a pump will lose one foot of priming ability.

For example, in Flagstaff, Arizona where the elevation is approximately 7,000 feet, the pump would have a suction lift of only 18 feet rather than the 25 feet at sea level. Table 3 shows suction lift at various elevations.

Table 4. Suction Lift at Various Elevations

Altitude			Suction Lift in Feet (Meters)
Feet (Meters)
Sea Level	10.0 (3.048)			15.0	(4.572)	20.0 (6.096)		25.0 (7.620)
2,000 (610)	8.80	(2.680)		13.2	(4.023)	17.6	(5.364)	22.0 (6.705)
4,000 (1,219)	7.80	(2.377)		11.7	(3.566)	15.6	(4.754)	19.5	(5.943)
6,000 (1,829)	6.90	(2.103)		10.4	(3.169)	13.8	(4.206)	17.3	(5.273)
8,000 (2,438)	6.20	(1.889)		9.30 (2.834)		12.4	(3.779)	15.5	(4.724)
10,000 (3,048)	5.70	(1.737)		8.60 (2.621)		11.4	(3.474)	14.3	(4.358)

Table 4 shows percentage drops in performance as elevation increases.

Table 5. Performance Loss at Various

Elevations

Altitude	Discharge Flow	Discharge Head
Feet (Meters
Sea Level	100%	100%
2,000 (610)	97%	95%
4,000 (1,219)	95%	91%
6,000 (1,829)	93%	87%
8,000 (2,438)	91%	83%
10,000 (3,048)	88%	78%

PAGE 12 — MQD2H/3H DIAPHRAGM PUMPS — OPERATION AND PARTS MANUAL — REV. #6 (10/27/11)