Rinnai highlights importance of hot water Legionella checks

Water system outfit Rinnai has highlighted the importance of Legionella checks in heating units and delivery systems amid the Covid-19 lockdown.

All hot water delivery systems in any commercial or institutional site need to be given detailed consideration to the potential of Legionella proliferation during the shutdown. 

That will necessitate that certain procedures and measures are carried out before the system can be made ‘live’ and function efficiently, the company said. 

ACOP L8 guidelines, produced and published by the Health & Safety executive, lists the details and necessary procedures to ensure system cleanliness.  

According to ACOP L8, continuous flow direct to outlet systems are low risk for Legionella, due to it allowing for a full turn-over of water volume, no stored water and accurate temperature control. 

To bring a continuous flow hot water heating system back to into active service, Rinnai advising the following: 

•With the water heaters still shut down allow fresh cold water into the system and flush all outlets for a minimum of five minutes. This will allow all stagnant water to be removed which should take any bacteria with it. Another method can be to flush the system with a suitable biocide chemical.  

•Once the above has occurred and, if the appliance has followed a regular and appropriate service regime, the water heater can be brought into service and the below steps carried out: 

1.Set appliance to 65 degrees Celsius, if it is not already.  

2.Open the gas supply. 

3.Turn on secondary pump, check water heater is operating correctly by checking gas pressures and allow to recirculate for no less than one hour. 

4.After one hour if possible, adjust TMVs to 55 degrees Celsius and flush all outlets for a minimum of five minutes.  

5.Carry out sample tests for all water outlets for any Legionella presence. 

6.If the appliance has not had a service within the last four or five months, then a full service should be carried out before above steps 1 – 5 are carried out.  

“Other modes of hot water delivery systems will have their own sets of procedures. Best advice to site managers and maintenance personnel is to ensure they should obtain specific sets of information and procedures for their particular system,” the company said. 

“That may be time consuming, but it is important to check for possible Legionella given that the lockdown has been here for several weeks – and it has been an ideal time for bacteria proliferation. 

“Or sites may want to consider that it is the perfect opportunity to switch to a continuous flow system of hot water delivery. This will ensure a limitless supply of hot water is available, provided there is no interruption to gas and water supplies.  

“Continuous flow is acknowledged as more technologically advanced, more efficient, more cost effective with less front-end costs and better whole-life economics.” 

Comprehensive Restart Kits are available direct from Rinnai. If there are any questions or queries regarding continuous flow hot water heating systems, contact Rinnai direct by telephone or email. 

Facilities manager, installers, site managers, contractors and all end-users simply call 01928 531870, select technical and if the call is not answered immediately leave a voicemail.  

Alternatively, Rinnai can be reached by email [email protected] or [email protected] or visit www.rinnaiuk.com and see the website homepage “Help Me Choose” or “Ask Us a Question”. 

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