QUOTE(wontdieone @ Nov 20 2025, 03:38 PM)
Hi all. For 2.5 storey house (master bed/bath on 2nd floor), 3 bathrooms on 1st floor, and 2 bathrooms on ground floor. I plan to get Grundfos CMBE 5-62 and Centon Serene Highlands 5.4kW Instant Water Heater to power the master bathroom rain shower. Would it work?
External booster pumps, especially powerful ones like Grundfos, are usually paired with storage water heaters like
CENTON Neptune, or if u prefer instant water heaters, the multi-point ones like
CENTON Forza (that comes with copper tank, with power rating of 5.5kW or 7.0kW).
CENTON Serene Highlands 5.4kW is a single-point instant water heater, and here's a few reasons that instant water heater might not be sufficient:
1. High Water Flow | Your water flow will be very high with Grundfos pump, hence 5.4kW power rated instant water heater might barely give u a lukewarm output water temperature (the higher the water flow, the lower the output water temperature). U might need a 7.0kW like
CENTON Forza (if your electrical wiring and component spec is sufficient to support such high power rating) to sufficiently heat up the water before reaching you. A storage water heater like
CENTON Neptune will definitely be sufficient, hence is the best choice.
2. High Water Pressure | That model is a single-point model (comes with a plastic tank), which can withstand up to 55psi water pressure only. You Grundfos pump might output water pressure that exceed that, which will damage the water heater's plastic tank in a long run. Hence, if u insist of using instant water heater, a multi-point model like
CENTON Forza is safer (can withstand up to 87psi), or best option, to go for storage water heaters like
CENTON Neptune (can withstand up to 116psi).
3. Shower Accessories Compatibility | U have to use the shower accessories that comes with that single-point model (else your warranty will be voided). Hence if u want to use your own sets of shower accessories (eg. those that built-into your bathroom walls), go for multi-point models like
CENTON Forza is safer (free to use with any shower accessories), or best option, to go for storage water heaters like
CENTON Neptune.