SCALA 2 Is the Future: Grundfos Phasing Out MQ3 Series

scala2 perfect water pressure ensures improved performanceSpring 2022 Update:

Grundfos has now released the SCALA1. if you want to check that out or learn all about the differences between SCALA1 and SCALA2, we have the resources for you.

Original blog post:

The latest and greatest in residential pressure boosting pumps is now officially the SCALA2 series. Our customers are very familiar with Grundfos. Though SCALA2 hit the market a few years back, many customers remained dedicated to the older MQ3 series for its reliability. So how does the SCALA2 vs MQ3 series measure up?

SCALA2 did have a few manufacturer flaws (more on that later), but they’ve now been fixed, and it is the superior pump. They have made it easier to meet the variable demands of your plumbing system while delivering the reliability and integrity you expect with Grundfos engineering.

When Will Grundfos Phase Out MQ3?

You could say that it’s already begun and probably will be complete in June. For customers who want to continue buying the MQ3 series, PlumbersStock will carry it as long as we can because we know plenty of people will still be looking for it. Here are the MQ3 models in question:

  • 115v MQ3-35 3/4 HP booster pump (all sold out)
  • 230v MQ3-35 3/4 HP booster pump (all sold out)
  • 115v MQ3-45 1 HP booster pump (all sold out)
  • 230v MQ3-45 1 HP booster pump (all sold out)

You no longer have to worry about horsepower when buying a residential booster pump. SCALA2 is built to meet your water flow demands. It ramps up and down when it needs to with its constant pressure system (more on that in a second). Here are the SCALA2 models in question:

Grundfos SCALA2 vs MQ3

Both models share many of the same standard features that you’d expect, like dry run protection and a max operating ambient temperature of 32 to 113-degrees Fahrenheit. Where they differ is what really matters. The SCALA2 is as quiet as a modern dishwasher, operating at 47 dba. Certainly, the show-stopper with SCALA2 is the intelligent pump technology that ensures perfect water pressure automatically. It works much like a variable frequency drive (VFD). The versatility ensures you have the machine you need. Remember that no matter what you want, PlumbersStock has the best prices on all kinds of Grundfos pumps.

scala2 vs mq3 pressure boost pump comparison

If you compare the specs on the 115v SCALA2 to the 115v MQ3, you will see a lot of similarities and a few important distinctions:

  • SCALA2 = rated head of 88.6 feet, max operating pressure of 145 psi, and max liquid temperature of 113-degrees Fahrenheit.
  • MQ3-45 = rated head of 75.5 feet, max operating pressure of 109 psi, and max liquid temperature of 95-degrees Fahrenheit.

Last, but not least, the engineers at Grundfos have been able to design more user-friendly controls and an easier installation process with the new SCALA2 series.

What Was the SCALA2 Recall About?

Back in 2019, Grundfos issued a recall of models within the PC codes of 1603 and 1901*. The issue was leak failure. It’s hard to say how widespread the issue was, but Grundfos advised/requested that if you had already installed the pump, then to keep it in place. Not all models were failing, but enough of them did that Grundfos reengineered the SCALA2.

*Signifying they were manufactured between the 3rd week of 2016 and the 1st week of 2019.

Save on Booster Pumps at PlumbersStock

Now that you know all the ins and outs of SCALA2 vs. MQ3, you’re ready to make a purchase. No matter which pump you choose, you can save at PlumbersStock. We have all kinds of booster pumps that will have you covered whether you have a house or a duplex. If you are buying in bulk, either because you are a contractor or are doing your own remodel, know that you can save even more with PlumbersStock if you contact us directly about special pricing.

12 thoughts on “SCALA 2 Is the Future: Grundfos Phasing Out MQ3 Series”

  1. Dear friends –
    Will the Scala2 lift water from a cistern?
    Approx 9’ from bottom of cistern to pump.

    Please advise

    • Sorry for the delayed response.

      Yes, it will. But not a lot of volume…it only has a 1-inch outlet. The good news is that means there will be plenty of pressure.

  2. I bought Grundfos Mq3-45 (115V) in May 2021 and had it installed in place of Grundfos Mq3-35 but the response when a tap is turned on takes a long time and the water pressure is terrible (worst than the Grundfos Mq3-35 , any suggestions. What should I do with the MQ3-45.I am in the Caribbean and bought it in Canada. Would it make sense to replace it with the SCALA2

  3. I decided to buy the MQ3-45 model to improve on the performance of theMQ3-35 model. The Mq3-35 model performed better than the MQ3 -45 model. I concluded that I got a faulty pump and but I was unable to find a Grundfos service provider in Grenada. Could you provide me with information regarding the warranty you offer. I was unable to get any service from the new pump I bought in Canada in May2021. I have gone from the ranks of satisfied repeat customer to that of dissatisfied customer.

    • We are sorry to hear that you are having problems. The manufacturer of the product offers the warranty to the original user only to be free of defects in material and workmanship for a period of 24 months from the date of installation, but not more than 30 months from the date of manufacture. Grundfos’ liability under this warranty shall be limited to repairing or replacing at Grundfos’ option, without charge, F.O.B. Grundfos’ factory or authorized service station, any product of Grundfos manufacture. Grundfos will not be liable for any costs of removal, installation, transportation, or any other charges that may arise in connection with a warranty claim.

      Fill out the required fields of Grunfos’ Customer Service form : Contact service | Grundfos. For more information, please refer to

  4. We have a SCALA2 3-45 AVCBDF, P/N 98562818. Installed about 6 years ago in a residential application to pressure all 3 levels of the home.

    Lately, the pump has been cycling on and then quickly cycling off again, very quickly (within about 1-2 seconds for the cycle up/down). Every time that happens, you can hear the pex system “thump”, maybe against a joist or other structural element of the home.

    There are no known leaks that would cause the switch to trigger cycle up.

    Is it possible to replace only the switch sensor?

    What other maintenance is suggested?

    Thank you.

  5. Purchased a scala 2 in 2018 to replace a 1.5 year old scala 2 that started leaking and making loud noises when running. The replacement started leaking after about 6 months I contacted Home Depot and they would not help so after lots of searching I found a distributor that sent me a replacement. Well I dealt with the leaking for a couple years until I had my basement refinished this year and finally installed the replacement. Wouldn’t you know that the replacement also leaks lol !
    All units should be replaced under a recall due to a defect in Engineering.

    • We are sorry to hear that you are having problems with your Grundfos SCALA2 Pump. Is the leak coming from the Shaft Seal? If so, it is normal that a slight leakage from the shaft seal of up to 10 ml per day or 8 to 10 drops per hour may occur. When the pump is started up for the first time, or when the shaft seal has been replaced, a certain run-in period is required before the leakage is reduced to an acceptable level.

      Under normal conditions, the leaking liquid will evaporate. As a result, no leakage will be detected. The leakage is visible where the screws are mounted on the base plate. If the unlikely event of an internal leakage occurs, the liquid
      will be drained through the bottom of the pump. Install the pump in such a way that no undesirable collateral damage can arise.

      Also, Always loosen and tighten the union nuts on the inlet and outlet ports by hand. Damage to the inlet and
      outlet parts increases the risk of leakage.

      For more information, please refer to page 13 of this Installation Manual.

  6. My scala 2 pump manufactured in 2018 just started leaking as well. The pump seems not to be able to get up to pressure and leaks a constant stream of water. If I turn up the pressure up then down it stops. The plumber is coming later today. This better be under recall.

    • Hi there! We are sorry to hear that you are having problems. For optimal performance, please make sure that you are using the SCALA2 Pump as intended. It is designed for pressure boosting of city mains water, water from roof tank, break tank, and ground tank, as well as water supply from shallow wells. If the leakage is from the pipe system or the non-return valve is not properly closed due to impurities, you may need to check and repair the pipe system or clean, repair or replace the non-return valve. If the leakage is located in the inlet pipe, you may need to repair the inlet pipe. For more information, please refer to pages 14 and 15 of this Installation Manual for more information on how to troubleshoot you pump. Hope this helps!

      Installation Manual


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