Grundfos MQ3-45 Capacitor
The Grundfos MQ3-45 is a 0.85 kW single-phase pressure booster pump commonly found in well & domestic pumps setups. Here's the capacitor it most likely takes and how to confirm the exact value.
- Pump type
- pressure booster pump
- Motor
- 0.85 kW · single-phase
- Run capacitor
- 40µF · 450V · CBB60
- Tolerance
- ±5%
- Application
- Well & domestic pumps
- Also sold as
- MQ3-45, MQ3-35, MQ Series, MQ3
A Grundfos MQ3-45 pressure booster pump typically takes a motor-run capacitor of around 40µF 450V (about 36-44µF). Treat that as a starting point, not a spec. Capacitor values vary even between identical-looking pumps, so read the rating printed on your existing capacitor (or the motor nameplate) and match the µF before ordering. Unsure, or the print worn off? Send us a photo and we'll confirm it.
Choose your terminal on the next page to match how your old capacitor's wires come out. Any of them works electrically, the terminal is just the connection. In NZ stock, dispatched in 1-3 working days. Prices in NZD · NZ addresses only.
Confirm before you order
- µF must match: the MQ3-45 needs 40µF (about 36-44µF), within ±5% of the label. Too low and the motor won't start; too high and it runs hot.
- Voltage can go up, never down: a 450V (or higher) cap is correct here; a 450V part safely replaces a 370V or 440V one. Don't fit below 450V.
- Check the terminal + size: make sure the new cap physically fits the housing and the connections match (or use a spade adapter).
- When in doubt, read your old cap: the printed µF and voltage on the part you're replacing is the final word.
Other Grundfos pump capacitors
Replacing the capacitor on a different Grundfos? These models have a confirmed or documented fitment too:
Browsing rather than replacing? All well & domestic pumps capacitors · Pump capacitor guide
Spotted a mistake, or want to confirm this fits your exact unit? Tell us. We read every message and reply within a working day.