Biocide and corrosion inhibitor

[Mr Blobby]

Should biocide and corrosion inhibitor be added to the water in the UFH pipes? 

Any reason not to?

If so then what product?

[JohnMo]

Biocide, if a low temperature system add biocide, if used for cooling add biocide. 

 

Use same make as the inhibitor so biocide and inhibit from same ame manufacturer), so there are no compatibility issues.

 

I used, Adey MC10+ Rapide Underfloor & Central Heating System Biocide, plus Adey MC1+ Central Heating Inhibitor.

[marshian]

I'm confused by the need to run Biocide (even if cooling) - if the circuit is shared with HW coil? surely the temp required to occasionally heat the HW via a coil would be enough to provide some sterilisation?

[JohnMo]

31 minutes ago, marshian said:

I'm confused by the need to run Biocide (even if cooling) - if the circuit is shared with HW coil? surely the temp required to occasionally heat the HW via a coil would be enough to provide some sterilisation?

So if cooling or low temp UFH the majority of the water stays in the UFH while you do DHW. A heat pump either does DHW or CH not both together. At the end of the DHW heating cycle you get a slug of hot water mixing with CH water, which is diluted very quickly when mixed with the UFH water and or fan coils. So the DHW demand, does little or nothing advantageous to preventing bio growth.

 

Best case you will heat the DHW circuit up to about 55 degs, but temperature is not held long enough to pasteurise the water, so really had little or no effect. It may even increase the bio growth by pushing water temp to a more ideal temperature.

 

For the sake of £30 I add biocide, it's cheap insurance, from issues later.

[Conor]

Are you using glycol? Inhibited glycol should be all you need. And water, obviously.

[Nickfromwales]

So, for completeness,

 

Q: Who here has specifically treated their system with biocide?

[JohnMo]

4 minutes ago, Nickfromwales said:

So, for completeness,

 

Q: Who here has specifically treated their system with biocide?

Me

33 minutes ago, Conor said:

Are you using glycol? Inhibited glycol should be all you need. And water, obviously.

I have no glycol, it was removed. So just the two chemicals mentioned above and 2x anti freeze valves (required for ASHP warranty).

 

Quick bit of research 

The Sweet Spot for bio film formation is 20 to 40 degC: Most common bacteria (including pathogens like Pseudomonas or Salmonella) thrive and rapidly create dense, stable biofilms in this moderate to warm temperature range. Optimal growth generally peaks around 37 degs.

 

Extreme Cold (< 15 degC): At lower temperatures, microbial metabolism slows down. Biofilm formation takes much longer (often weeks instead of days), though the resulting biofilms can be highly resilient and adhere strongly.