Boiler Blowdown Systems

By law, steam boilers in the UK need to be regularly maintained to help ensure safe and efficient operation.

An important part of the maintenance routine is regular blowdown of the boiler water which helps maintain the water quality in the boiler and the system overall, of which there are three main types: bottom blowdown, TDS blowdown and level gauge blowdown.

Bottom Blowdown

  • Carried out by the bottom blowdown valve on the bottom blowdown line
  • Required to remove sludge and sediment deposits at the bottom of the boiler
  • Sludge build-up can cause potentially dangerous damage to boiler tubes
  • 3-5 second purge of the bottom of the boiler
  • Required daily or per shift
  • Automated or manual depending on site preferences.

TDS Blowdown

  • Continuously blowdown via an electric TDS valve
  • Required to keep Total Dissolved Solids in the boiler water to within prescribed levels (approx. 2000 ppm for small industrial shell boilers and 3500 ppm for larger boilers)
  • Excess TDS levels leads to carry over and poor water level quality - What is TDS?

Level Gauge Blowdown

  • Level gauges on the side of the boiler are drained regularly to avoid dirt build up
  • Scale and dirt build up impairs proper reading of gauge glasses resulting in potentially dangerous misreading of the boiler level
  • Carried out manually by drain cocks at the bottom of the gauges
  • Required to be carried out regularly by law on boiler arrangements

The Blowdown Vessel

As these types of blowdown are at boiler temperature and sending these blowdowns straight to drain is a Legionella risk, a blowdown vessel is required to receive the blowdowns. This allows the hot discharged water to cool before being sent to drain.

Valveforce follow the CEA’s latest guidance on Boiler Maintenance (BG01 – Guidance on Safe Operation of Steam Boilers) and Blowdown Systems (BG03 - Blowdown Systems Guidance for Industrial Steam Boilers) when advising customers on blowdown design and new equipment.


Valveforce offers peace of mind by ensuring that your steam boiler plant is compliant with all regulatory standards, including the CEA’s BG03 and necessary HSE guidelines, and ensures that your bottom blowdown works efficiently and effectively.

You can also rely on our team of steam solutions experts to offer advice and undertake complete boiler house and boiler surveys.

In the boiler house we:

  • investigate boiler feed water conditioning
  • to supply boiler feedwater tank and deaerator plant equipment and accessories
  • provide water treatment equipment, including water softening and reverse osmosis (RO) plant

For the steam boiler we:

  • review boiler control equipment for level control
  • check boiler blowdown
  • test boiler heat recovery equipment

From the boiler house surveys, Valveforce produce detailed reports to ensure that your boiler blowdown valve and boiler house are up to date and in keeping with the latest standards and legislation.

If you would like further information and advice, please contact Valveforce on 0121 711 1908 and ask for the boilerhouse specialist team.


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Product Variations

Valveforce can provide a turnkey solution for its steam boiler blowdown solutions, including:

  • site surveys
  • bespoke boiler blowdown system design and construction
  • installation
  • commissioning
  • servicing/maintenance contracts

Valveforce can also supply and install the following solutions and equipment:

  • Complete TDS System inclusive of:
    • Electric TDS Control valve with
    • TDS Controller - panel mounted
    • TDS Probe
    • Spool piece
    • Valves
    • Sample cooler
  • Automated Blowdown Valves:
    • Big brands including Gestra and Spirax
    • Alternatively, our long-pattern pneumatic ball valves designed for blowdown applications are a cost-effective solution to the more traditional globe valve design and will replace existing valves
  • TDS Control Panels
    • With modulating controller for the TDS system
    • With Blowdown timer for bottom blowdown
    • Within Valveforce designed control panels
    • Or incorporated within the existing boiler panel
  • Level Gauge Repairs and Spares
  • Bottom Blowdown Vessels & Accessories
    • New and replacement blowdown vessels conforming to BG03
    • Water cooling sets
    • Air vents

To discuss your boiler blowdown requirements, contact Valveforce on 0121 711 1908 or email

Case Study - Boiler Upgrade at Milliken Industrial for Blowdown TDS and Level Control Docs

Milliken, a floor tiling manufacturer, recently needed a solution to their boiler level controls and bottom blowdown system that was out of date.

The issue with having out of date controls is that getting replacement spares can no longer be done, leading to serious issues when parts malfunction.

The company also wanted to update the boiler house to unmanned status by adding a PM5 system, which means a specially trained boiler supervisor does not need to be onsite every 24 hours in the scheme they have.

With our expertise, Valveforce advised on the best options and equipment to use to achieve these upgrades, including new TDS controls.

The turnkey project included the design of a new control panel for the whole boiler, new pipework on the TDS and a completely new TDS system.

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Valveforce Ltd specifically work alongside BSi for all aspect of our company activities by installing a UKAS accredited quality system in accordance with the guidelines laid down in ISO 9001:2015.