Boiler Scale Inhibitors & Polymer Sludge Conditioners

The formation of deposits of scale or baked on suspended solids will reduce efficiency and may make the boiler unsafe to operate.

Polymer Phosphate Scale Inhibitors

Boiler scale control; Scale is caused by the accumulation of hardness salts in the boiler water which, if not removed can cause localised overheating, reduced heat transfer efficiency, and in severe situations tube failure.

Hardness salts can either be removed before they enter the boiler system or they can be treated inside the boiler itself with suitable antiscalants/scale inhibitors. Even when hardness is removed from the make-up water it is important to use an appropriate scale control programme within the boiler water to ensure that any hardness slippage is prevented from causing troublesome deposits.

If you are a water treatment specialist, FM or maintenance company who regularly resells water treatment products to your customers why not apply to become an Accepta Registered Reseller.

To ensure that such boiler systems are well maintained and operate at optimum efficiency it is essential that the correct water conditions are maintained at all times. This can be achieved using carefully selected feed water scale and corrosion inhibitors designed specifically for industrial boilers and steam raising plant.
Accepta’s technically advanced boiler water scale control inhibitors and sludge conditioners are scientifically formulated to combat the detrimental effects of scale build-up and work in conjunction with the Accepta’s oxygen scavengers and alkalinity builders to provide total system protection.

How Polymer Sludge Conditioning Works

The scale inhibiting polymer keeps suspended solids moving freely to prevent insulating scale deposits forming on heat transfer surfaces by disrupting scale formation by destabilising the calcium agglomerations so that they can easily be removed by boiler blowdown. 

Often this is combined with a phosphate treatment which precipitates the calcium as any of several insoluble calcium phosphate compounds to maximise scale prevention.

Scale Disruption

Popular Boiler Scale Inhibitor & Sludge Conditioning Products

FDA Approval

Sludge Conditioner


FDA Approval

Excellent for control or removal of Iron, Calcium Phosphate deposits & general dispersancy. FDA Approval.

Sludge Conditioner

Excellent for control or removal of Iron, Calcium Phosphate deposits & general dispersancy.

Sludge Conditioner


FDA Approval

Sludge conditioner based on a blend of FDA approved polymers for max performance

Scale Inhibitor / Sludge Conditioner


FDA Approval

Phosphate based scale inhibitor incorporating an FDA approved polymer sludge conditioner.

Scale Inhibitor / Sludge Conditioner

Phosphate based scale inhibitor incorporating a polymers sludge conditioner.

Scale Inhibitor

Alkaline Phosphate Scale Inhibitor for High Pressure Steam Boilers (>20 bar)

Boiler Chemical Dosage Form

Complete as much of this form as possible to get your bespoke boiler chemical dosage treatment recommendations.

Selecting your Boiler Scale Inhibitor

Accepta provides two kinds of scale inhibitor – Polymer only and Polymer Phosphate, the latter of which is the required option under the following conditions:

  • Phosphate must be used in boilers operating at pressures above 19 bar (150 psi)
  • The ‘natural’ Alkalinity of the make-up after sulphite addition is less than 20% of the TDS or make-up is dealkalised
  • Or when the make-up water is not efficiently softened

Polymer Phosphate treatment regimes precipitate magnesium & calcium hardness salts from boiler make-up water in the form of hydroxyapatite and serpentine. These compounds form sludge, which, when properly conditioned with polymers, is removed from the boiler during blowdown. When a significant excess of soluble orthophosphate and free hydroxide (caustic) alkalinity is maintained in the boiler water, calcium carbonate formation can be virtually eliminated. Polymeric dispersants or sludge conditioners are added with the phosphate to condition the sludge for improved removal from the boiler. See Accepta 2112 & 2347 for high-quality boiler phosphate treatment.

boiler scale control chemicalsCorrect Boiler Treatment is immensely important as poor treatment regimes can lead to significant increases in operating costs with scale acting as insulation on the boiler tubes reducing the amount of energy transferred from fuel burn to boiler water temperature. With 80% or more of boiler house costs coming from fuel that can mean a lot of money being wasted out of the smokestack.

Dosed into the feed water tank Accepta’s Polymer Phosphate scale treatment chemicals are ideal additions to your boiler treatment program and can be combined with Oxygen Scavenger Corrosion Inhibitors & Multi-functional Boiler Chemicals such as Accepta’s range of blended Tannins and Sulphite treatments.

A Polymer Phosphate treatment helps to keep hardness in suspension by converting it to a sludge which can be removed by blowdown. Your makeup water should be softened down to a level below 1ppm of hardness with your Water Softener tested weekly. If you require a Water Softener speak to Accepta today.

Silicate Scale Prevention

Silicate scales can easily be formed in boilers at moderate temperatures and pressures. They are particularly likely where the feed water silica content is a high proportion of the dissolved solids and the feed alkalinity is low.

Due to their clingy nature and low thermal conductivity, silicate scales can be particularly damaging and should be prevented by adopting all of the following measures:

  • Adequate pre-treatment such as lime softening, ion exchange and reverse osmosis.
  • Maintain adequate phosphate or carbonate reserve
  • Maintenance of a silica caustic alkalinity ratio of 0.4 : 1
  • Limitation of the boiler water silica level down to 0.02ppm

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