Allmech Managing Director Lionel Maasdorp describes an ongoing maintenance and water treatment success story at Warmbaths, where demineralised feedwater was causing corrosion and scaling.
At Warmbaths, A Forever Resort, two coal-fired boilers sit at the heart of daily operations. However, the resort was struggling with inefficiency and high consumption of coal and chemicals.
When one of the boilers was opened for inspection, it was obvious that corrosion and scaling were already taking their toll. Significant capital was required to bring the boiler back to an acceptable standard. Forever Resorts engaged Allmech, a leading local supplier of boilers and water treatment solutions, to review the water treatment setup and provide a second opinion.
Investigating the root cause
When Allmech assessed the site, a demineralisation plant was supplying feedwater to the mid-pressure coal-fired boiler. Allmech Managing Director Lionel Maasdorp explains that, on the surface, highly purified water may seem like the ideal choice. However, ‘clean’ demineralised water absorbs minerals from whatever it comes into contact with. In a carbon steel boiler system, this can accelerate corrosion in the boiler shell, tubes and condensate lines.
“Considering the water was being used for a mid-pressure coal-fired boiler, we did not agree with the use of demineralised water,” Maasdorp says. “Water that cleans can be corrosive in the boiler and pipes.”
Low pH levels compounded the problem, particularly in the condensate lines, where oxygen-related corrosion was evident. Steam traps were clogging with rust particles. The resort was in the process of replacing some metal pipework with PVC to mitigate the effects, but when the boiler was opened, it was clear that acid washing and repairs to boiler tubes were required. Forever Resorts decided to re-examine their system requirements and setup, and asked Allmech to step in.
A change in strategy
After analysing the incoming raw water, Allmech recommended discontinuing the demineralisation process and instead repairing and optimising the site’s softeners. This reduced unnecessary chemical use and enabled a more appropriate treatment strategy.
The team then started using Allmech A103, a blended boiler treatment designed for mid-pressure systems. Maasdorp says that A103 performs several functions simultaneously:
- An oxygen scavenger removes dissolved oxygen.
- A pH booster stabilises and elevates alkalinity.
- A polymer keeps suspended solids in suspension so they can be removed through blowdown.
- A vapour-phase component carries over into the steam to protect condensate lines from corrosion.
Allmech also implemented weekly check-ins to monitor the effectiveness of the new approach. Total dissolved solids (TDS) were monitored, blowdowns adjusted, and chlorine and pH levels in the condensate tracked closely. Over time, test results began to shift in the right direction and pH levels increased. Rust particles in the feed tank decreased, while corrosion stabilised.
Visible results
When the boiler was opened after the first year under Allmech’s treatment programme, visible corrosion had already begun to reduce. Maasdorp says some debris remained, but this likely originated from previously damaged condensate lines.
The original equipment manufacturer recommended another acid wash. Allmech did not believe this was necessary, but the procedure was carried out.
At the most recent inspection, the difference was clear. “The tubes were spotless,” says Maasdorp. “There was only evidence of old scale that had flaked off in a hard-to-reach area. There were no signs of excessive corrosion, and the particles that had previously been present in the feed tank were no longer there.”
A clean boiler eliminates the need for further acid washing – a harsh and destructive process. Avoiding these interventions extends the asset's lifespan.
Operational impact
For Jean Nel, Boiler Manager at Warmbaths, the improvements have been significant. “We saw a lot of changes. The boiler was more efficient, with less coal usage,” he explains. “There was less corrosion in the boiler and less scale detected on the inner tubes from the time Allmech took over the boiler water treatment.”
The resort has also seen improved chemical efficiency compared to its previous setup, and Nel believes the longevity risks have been effectively addressed.
“Without a good water treatment partner, you can damage your boiler and tubes. It can cause a lot of damage in the long run,” he says. “The value of Allmech’s service is up to standard. They are always a phone call away and always there to assist us. We can say with an open heart, we are happy to have them on our side.”
A partnership approach
Maasdorp is quick to credit the site team for their role in the turnaround. “I am always proud when a client’s team works well with our staff. A good team working together helps to look after a company’s assets and livelihood by reducing unnecessary costs.”
With the right treatment strategy and disciplined monitoring, boiler water chemistry becomes an asset protection tool rather than a recurring repair risk.
