Vacuum Cleaners Discussions

Technically, the Rainbow vacuum was the first to not lose suction.  It uses a more primitive dual cyclone design with water as a pre-filter.   If the Rainbow didn't have such a ridiculously high price and clumsy power nozzle, it would be a pretty good vacuum.  I don't know why they require you to hold a button down to keep the power nozzle operating.  One would think that they would use a simple 2-way switch.  All that on/off cycling can't possibly be good for the power nozzle motor.   The Rainbow uses an innovative brushless motor.  It would be a pretty good $800 vacuum with a better power nozzle. 

Rainbows in my experience do not have a lot of suction to begin with and very weak airflow. Example, a fairly recent E2 I have in good condition with the HEPA filter removed so there are no restrictions anywhere only pulls 50 inches of water lift at the hose end and fails to pull my BAIRD meter off the bottom of the scale. An old and inexpensive Hoover PowerMax canister pulls 58 inches of water lift at the hose end and registers a 7 on my BAIRD meter. A Kenmore Elite canister pulls over 84 inches of water lift at the end of its eight foot long hose (with a suction leak due to the irregular shape of the hose end) and pulls my BAIRD meter right off the scale, past 10. For what Rainbow charges their measured performance is quite low.

WOW, I realize how dead this site is anymore when I see a resurrected thread from 2007, and that's the newest post. In any case the OP, back in 2007, mentioned the Rainbow was a good machine but overpriced. Agreed, there is a contender on the market now, the Sirena, that is comparable to the Rainbow at a lower price around $899,though with good negotiation skills you can get it for less. Time will tell if the quality and longevity is there as I have a 40 year old Rainbow, I will let you know if my three month old Sirena lives that long, but it does have a 10 year motor warranty. Sirena uses an Italian designed, Chinese built motor that moves 90 CFM on high speed, and 18CFM on low. As a collector I can say that it is a pretty good vacuum. Maybe not as refined as the Rainbow, but everything is very livable. It does not have the digital motor. No direct connect wands. Slightly larger water basin. I am not a fan of the power nozzle (a direct copy of the E2 nozzle complete with the hold me to use me switch on the hahdle. Only drawback, as with any water vac, is that your daily maintenance is a little more than a bagged machine that you just wrap back up and put in the closet, but if you are dedicated to a water vac, this is a lower cost alternative.

Just, Rainbows don't have "digital motors" by which I think you really mean brushless reluctance motors. Rainbow uses and has always used very conventional commutated universal motors. The current motor is a small single stage motor, not the big two stage motors of old. They have very weak airflow and suction compared to modern canister vacuums. My E2 barely pulls my BAIRD meter off the bottom of the scale at 0. An old Electrolux Silverado pulls the BAIRD meter up to 7 and my modern Kenmore Elite pulls the BAIRD meter off the scale past 10. Also, 90 cfm airflow is only so-so. Most modern canister vacuums produce more. A simple Pro-Team back pack vacuum pulls 110 cfm. An old Hoover Dimension 1000 pulls more than that. As for filtration, water vacs still need HEPA filters because all of the dust entering the water chamber is not entrained in the water. Very light particles get past the motor and require HEPA filtration to capture. A modern bagged canister vacuum using a good cloth HEPA dust bag and filters does every bit as well.