Pressure-Maintaining Dosing & Make-Up Units: Problems Often Lie in the Dosing Step

Published: 2026-10-22 11:37:05 Views: 4 Source: This site

In the machine room water system, pressure stabilization, water replenishment, and chemical dosing have long been handled separately. The pressure tank takes up one space, the replenishment pumps take up another, and the dosing unit takes up yet another, with piping winding back and forth among the three.

At the design stage, each is drawn separately; at the procurement stage, each is bid separately; and after installation, each is managed separately. The problem lies precisely in those words "managed separately."

Over the past two years, working on retrofit projects, one change has been quite noticeable: the practice of combining the three functions into a single unit has become more common. The reasons are not complicated, but each one is quite practical.

The existing heat exchange rooms and pump rooms were already packed, so adding a separate dosing unit meant either squeezing it into a passageway or eating into maintenance space. Some projects, in order to fit equipment in, narrowed walkways so much that people had to sidle through — a maintenance headache for years afterward.

After integration into one unit, the pressure tank, pumps, and dosing tanks share a single base, reducing the footprint and shortening the piping. This is not just about saving a bit of space; it solves the prerequisite problem of "whether it can fit at all."

The pressure stabilization and water replenishment section consists of pumps, a pressure tank, pressure sensors, an intelligent electrical control cabinet, and a base.

During operation, the pressure sensor continuously monitors system pressure changes and determines whether to replenish water or release pressure accordingly. When pressure is low, the pump starts to replenish water; when pressure is high, pressure is released. The whole process requires no human attendance.

This logic is fairly mature, and most projects can define it clearly at the design stage. The real hidden risk lies in the next part.

For algae growth and scaling in the system, there are generally three treatment methods: the ozone method, the ultra-low-frequency vibration method, and chemical dosing. The first two involve high equipment investment and maintenance barriers, so in actual engineering, the third is more commonly used — dosing scale and corrosion inhibitors and biocides/algicides.

It requires proper dosage and dosing rhythm: the amount must be appropriate, and dosing must be continuous or timed. Too much wastes chemicals and drives up operating costs; too little fails to prevent scaling or suppress algae. What manual dosing finds hardest to guarantee is precisely the rhythm — forgotten when busy one day, then doubled the next, leaving the chemical concentration in the system constantly fluctuating.

This is why the combination of automatic dosing technology and complete dosing equipment is increasingly common in actual projects.