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Variable Frequency Drive VS Standard System with big pressure tank and switch.

Updated: May 31, 2020

We install both types of systems, variable frequency or standard and can rely on both systems to be solid in their performance.

Lowest price point, in most situations.

A pressure switch and large pressure tank with a control box and possibly a pumptec, is a control system that has been around for a long time. . Starting a pump motor creates heat because of the inrush of current during start-up. The pressure tank needs to be big enough to allow the pump to run one minute to cool itself before shutting down. This why we look at the pressure in the tank, inspect the switch and check the cut-in and cut-out cycle of the pump. If the pressure tank is faulty, it may not allow for the motor to have a run time of one minute. This kind of fast cycling can shorten the life of the motor. We look for this when we do service calls. You may notice the pump kicking in a lot, or too often, that is a sign you should have us check it out.

This type of system can run for years without any trouble as long as it was sized correctly when installed. The main cost in your system will be the submersible pump, wire and pipe along with the pressure tank ( in this first, standard system - in the next two systems the tank will be small and much less costly).

Your pressure tank is set at 2psi below your cut-in pressure so for a 40/60 pressure switch that would be 38psi. To check your tank pressure turn power off to your pump, empty your tank and use a gauge to check it. There is always going to be a change in water pressure of 20 psi as the tank and pump work together to supply your water. This why the constant pressure system may be the right choice for you.

There are two options when considering a change to constant pressure.


Medium price point, ( savings on large pressure tank if new installation or small tank upgrade/ drive upgrade opportunity if pressure tank fails in existing system )

We can use a single phase motor and pump combo with a Subrive/ Monodrive Utility. This gives you soft start, which does not heat your pump up each time it starts, and constant, city-like pressure while your water usage varies. It also protects your pump in many ways, including, surge protection, short circuit, underload, overheat controller, undervoltage, broken-pipe detection*, locked pump, user-configurable underload off-time*, open circuit, optional moisture/wet-floor sensor protection.

There is a small pressure tank which saves money vs the larger tank, and the pressure sensor is not a mechanical switch. An added benefit to a low voltage pressure sensor is safety; There is voltage running through a regular pressure switch that could shock the person trying to adjust it.

This option can be fitted to most pump systems out there, even on surface pumps. Systems that previously had a control box and large pressure tank.!!


Top Price Point ( savings on tank and wire size down your well - deeper well, longer run to well from house, more savings on wire )

We can upgrade you system further with a Subdrive Connect variable frequency drive with a three phase motor and pump combo. This combination uses the powerful characteristics of the three phase motor and matches it with the next level up electronics of the Subrive Connect series controller. This drive is more expensive but you will save on the pressure tank and on the wire down the well. The Subdrive Connect gives you the same pump protection as the single phase drive.... and more... and allows you to control more of the pumping parameters from the drive or from your tablet or phone.

Your choice. We trust all three system types and enjoy installing them for our customers.

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