Pricing
Gas Interlock System Cost
Interlock pricing is driven by three things: the size of the gas solenoid valve, how the proof of ventilation is sensed, and how far the cabling has to run. Everything else is predictable.
- Fixed-price quotes after a survey or a few clear photos
- Supply-only parts available from stock if you have your own engineer
- No call-out mark-up on planned installations
What makes up the price
| Element | What drives the cost |
|---|---|
| Interlock controller / panel | Model, number of zones, whether gas detection or proving is integrated |
| Gas solenoid valve | Size — a 28mm valve is a fraction of a 54mm or flanged valve |
| Proof of ventilation | Air pressure switch is the cheapest; duct airflow sensors and current monitors cost more |
| Emergency stop | Number of buttons and escape route positions |
| Labour | Cable routes, containment, access above ceilings, pipework alterations |
| Out of hours | Overnight or weekend working to keep the kitchen trading |
Ongoing costs
- Annual interlock test and certification, usually combined with your gas safety inspection
- Replacement air pressure switch or solenoid coil if a component fails — both are stock items
- Nothing else: an interlock has no consumables and no subscription
Getting an accurate figure
Send a photo of the gas entry pipework and meter, a photo of the extract fan or its isolator, and the make and model of any existing panel. That is normally enough for a firm price without a chargeable survey.
Frequently asked questions
Is a cheap screwfix-style interlock kit worth fitting?
Trade-counter kits can be fine electrically but often come with an undersized valve and no commissioning certificate. The valve must match your gas rate, and the installation must be tested and documented to satisfy an inspector or insurer.
Do you offer supply only?
Yes — replacement interlock systems, air pressure switches and gas solenoid valves are held in stock for collection or next-day dispatch.
Is the annual test included?
The first year's test is included on new installations we commission.
Related guides
Interlock Installation
Kit selection, 28mm and 35mm valves, wiring and commissioning.
Gas Interlock Systems
The pillar guide: how interlocks work, standards and fault-finding.
Replacement Systems
Replacement panels, valves and complete interlock kits in stock.
Servicing & Testing
Annual interlock testing, certification and planned maintenance.
Manufacturer Guides
Merlin/S&S Northern, Medem, Flamefast, Intelligas, Duomo.
Parts in stock — ready to fit
Held in UK stock and carried on our vans, so most jobs are fixed in one visit.
Replacement gas interlock systems
Merlin, Medem, Intelligas, S&S Northern
In stock today
Air pressure switches
Fan & gas proving pressure switches
In stock today
Gas solenoid valves
Normally closed safety shut-off valves
In stock today
Quick release gas catering hoses
Commercial ranges, bays & mobile catering
In stock today
Super universal thermocouples
Fits most commercial gas appliances
In stock today
Need a part fitted?
Same-day engineer dispatch with these parts on the van.
Gas Safe Registered
Commercial catering & plant
24/7 UK Response
Same-day emergency dispatch
Vetted Engineers
DBS checked for schools & care
Transparent Pricing
Fixed callout, quoted parts