MQ3-35 3/4 HP Pressure Booster Pump

How to Identify and Fix Common Gardening Problems ?

We provide a variety of viewpoints on how to identify and fix common gardening problems. Our sources include academic articles, blog posts, and personal essays from experienced gardeners :

Pump Won`t Start

A booster pump that won`t start means that water will not be available to any outlet fed from the pumps. There are several reasons why a booster pump doesn`t start including a lack of power, water in the break tank, tripping, sensor failure, problems with the control panel and motor failure.

The pump will not restart after an alarm/fault. The Auto-reset function can be activated/deactivated by press- ing the on/off button for 5 seconds. Note: When water is consumed, the pump will start and stop automatically, whether the Auto-reset light is on or off.
Its replacement is the MQ Successor 3-45, an “on demand” pump that offers slightly higher flow/pressure performance and better functionality.
The impeller is partially clogged – back flush to clean or remove to clean. The clearance between the impeller and casing is excessive – adjust the impeller clearance. The suction head is insufficient – ensure the suction line valve is fully open and the line unobstructed.
The most common water-pump failure is due to worn bearings. Water pumps move a tremendous amount of coolant, and they just simply wear out over time. Belt tensioners can rattle when they`re worn out. You can spin the pump by hand when the belt is loose to feel if the rotation is smooth or notchy.
Start by checking that the well switch located near your pressure tank hasn`t been switched off. Then check the well`s double-pole circuit breaker to see that it hasn`t tripped. If it has, reset it. A breaker that keeps tripping likely means a problem with the well pump, and you`ll need to call a pro for that.
The Grundfos pump has 3 control modes (proportional pressure, constant pressure and constant curve). Each control mode has 4 settings to choose from. The user interface has 1 push button, one red/green LED and 4 yellow LEDs. When you switch on the pump, it runs with the factory pre-setting or the last setting.
The pump is factory-set to three bar outlet pressure which can be adjusted according to the system in which it is incorporated. The tank precharge pressure is 1.25 bar (18 psi).
In most of these cases, 40 psi should be more than enough, and since most modern tire designs will allow up to 44 psi (in some cases more) this is not a problem. If you have a heavily loaded vehicle, up to 44 or even higher is ok if the tire allows it, but this is a little high for most vehicles.
flow No change from standard CR Air-cooled Top The Grundfos CR Cool-Top pump is specially designed to handle liquids from 248°F to 356°F (120°C to 180°C).
First, catastrophic failure to your water pump is possible but unlikely. This would include things like the actual pump impeller coming off the shaft, pump blades chipping or falling off or other damage that would cause water to stop flowing.
The primary specifications to consider when selecting booster pumps are flowrate, pressure boost, horsepower, and power rating. Maximum flowrate describes the highest achievable rate of volume discharge through the pump.
Dry running your pump causes friction, and this friction is strong enough to heat up the impeller, causing it to melt. ² Even minor melting is severely detrimental to your pump`s performance, potentially causing it to seize up and stop working at all.

Discover Relevant Questions and Answers for Your Specific Issue

the most relevant questions and answers related to your specific issue

I have a pressure booster pump installed which turns on automatically when we open the tap and turns off by itself when we close the tap, but when power goes and comes back(common in india), the pump will turn on even with no tap opened and does not turn off automatically and goes on running, some kind of airlock problem I think, when we just shut off and on water input several times, it again starts working well
ANSWER : Check to see if the output pipe has water in it when the pump swutches off the pump needs to be primed at all time what we normally find cases like this is the pump is higher than the supply or there is an air pocket on the output where the pressure sensor is

The pump alarm light is on and there is water in the tank and nothing has changed, just stopped working. Have used the bleeder and water shot out and now will not work at all. Any suggestions
ANSWER : Press the on/off button once to reset the alarm and once again to start the pump.
If the auto reset light is on, the pump will attempt to restart in 30 minutes.
If the auto reset light is off, press and hold the on/off button for 5 seconds.

Why does my Grundfos MQ water pump keeping kicking on, even when there is no water demand?
ANSWER : Is it newly installed or has it been working for a while till you noticed it?

How do i increase the pressure in the in-built pressure tank
ANSWER : Right after the discharge outlet, a non-return valve or check valve is usually installed. Check this one out, maybe it is worn out. You may have to replace it. Do this and get back to me if it does not work out.

Grundfos MQ3-35 hums loudly and does not pump. Alarm light does not go on. Pump seems “happy” but when a tap opens and the pump turns on, there is no boost in pressure and the pump just hums loudly… definitely a different noise from normal operation. Seized? Vapor lock? Any help is greatly appreciated.
ANSWER : Hi, seems like the capacitor gone bad or a seized motor. I just fixed mine cranking the motor manually with the use of a flat head screwdriver. In the back of the motor there is a rubber plug about the size of a dime. Take it off an insert a long flat-head screwdriver and crank the motor clockwise a few turns. Remove the screwdriver and try to operate the pump as usual. Good luck …

Grundfos MQ 35
ANSWER : Check the capacitor or the centrifugal switch.

Pump leaks from the bottom after running, is this normal?
ANSWER : No . the problem is that the ceramic seal that seals between the fluid and the motor and bearings is leaking ( probably from running dry) or the rubber that holds the carbon seal insert has a crack. Suggest you pull the pump down to fix it otherwise the water/ fluid will get into the bearing of the motor and will cause a major failure

How to connect iton to 220 volts – Grundfos MQ3-45 1 HP Pressure Booster Pump
ANSWER : Http:// what i have researched you have to buy a 120 volt pump or a 220 volt pump you cannot wire it both ways. The pictures shown on that pdf show where to put the line 1 and line 2