The Sentinel X700 Biocide (MPN X700) is a specialist treatment formulated to protect underfloor heating systems from biological contamination caused by bacteria and fungi. Due to their lower operating temperatures and slower flow rates compared to traditional radiator systems, underfloor circuits are more susceptible to microbial growth if left untreated - which can lead to blocked pipework, restricted manifold ports, unpleasant odours, and internal corrosion. X700 is dosed alongside Sentinel X100 Inhibitor to keep pipework clear and heat distribution reliable across every zone.
Underfloor Heating
System Type
1L per 300L System
Dose Rate
30 Minutes
Circulation Time
Primary Circuit Only
Use Location
X100 Inhibitor
Pairs With
Corrosive Product - Handle With Care
Sentinel X700 is classified as corrosive to metals and to skin, and causes serious eye damage, and is hazardous to the aquatic environment. Suitable protective clothing, gloves and eye protection must be worn when handling, and the product must not enter drains or watercourses. Always read the safety data sheet before use.
Primary Circuit Use Only
This product is only for use in the primary circuit of underfloor heating systems and should not be mixed with other cleaning products other than those specifically approved by Sentinel.
Dosing Instructions
In new systems, add 1 litre of X700 during the final fill. In larger systems, dose at 1 litre per 300 litres of system volume, and circulate for 30 minutes to ensure complete distribution.
Purpose-Built for Underfloor Systems
Specifically formulated to address the lower operating temperatures and slower flow rates of underfloor heating circuits, which make them more vulnerable to microbial growth than standard radiator systems.
Prevents Blockages and Odours
Controls the bacterial and fungal contamination responsible for blocked pipework, restricted manifold ports, and unpleasant odours in affected systems.
Protects Against Internal Corrosion
Helps prevent the internal corrosion that biological contamination can cause within underfloor heating pipework over time.
Compatible with X100 Inhibitor
Designed to be used alongside Sentinel X100 Inhibitor at first fill or following a full system clean, for combined biological and corrosion/scale protection.
Long-Lasting Protection
Provides long-lasting protection against bacteria and fungi once correctly dosed and circulated through the system.
Quick to Dose
A straightforward dosing process that is easy and quick to apply either at first fill or as part of scheduled system maintenance.
| Product Identity |
| Manufacturer |
Sentinel (Sentinel Performance Solutions) |
| Product Name |
Sentinel X700 Biocide |
| MPN |
X700 |
| Application |
| Intended Use |
Underfloor heating primary circuits |
| Recommended Pairing |
Sentinel X100 Inhibitor |
| Not Suitable For |
Mixing with other cleaning products not specified by Sentinel |
| Dosage |
| New Systems |
1 litre during final fill |
| Larger Systems |
1 litre per 300 litres system volume |
| Circulation Time |
30 minutes minimum for full distribution |
| Safety Classification (per SDS) |
| Corrosive to Metals |
Category 1 |
| Skin Corrosion/Irritation |
Category 2 |
| Serious Eye Damage |
Category 1 |
| Aquatic Hazard |
Acute Category 1 / Chronic Category 3 |
| PPE Required |
Protective clothing, gloves, eye protection |
Why do underfloor heating systems need a biocide?
Underfloor circuits run at lower temperatures and slower flow rates than radiator systems, which makes them more susceptible to bacterial and fungal contamination if left untreated.
How much X700 do I need?
In new systems, add 1 litre during the final fill. For larger systems, dose at 1 litre per 300 litres of system volume.
How long should I circulate it for?
Circulate the system for at least 30 minutes after dosing to ensure complete distribution throughout the whole system.
Can X700 be used with other cleaning chemicals?
No. This product should not be mixed with other types of cleaning product other than those specifically approved by Sentinel.
Is X700 safe to handle?
It is classified as corrosive to metals and to skin, and can cause serious eye damage. Always wear suitable protective clothing, gloves and eye protection, and read the safety data sheet before use.
Should X700 be used alone or with an inhibitor?
For efficient long-term operation, underfloor systems should be treated with both Sentinel X700 Biocide and Sentinel X100 Inhibitor at first fill or following a clean.
