If you have ever had an LPG delivery, expected everything to carry on as normal and then found your heater refusing to fire, you are not alone. It is a common situation that catches many people off guard. After all, you have just topped up your fuel supply, so the system should be working better than ever.
In reality, the delivery itself can introduce a few temporary issues into the system. In most cases, the heater has not “broken” at all. Something in the fuel supply or safety system has simply interrupted the flow of gas.
The good news is that these problems are usually straightforward to identify and resolve. In many cases, it is not a major fault, just a system that needs resetting, clearing, or checking.
What is actually happening
An LPG system relies on a steady, uninterrupted flow of gas at the correct pressure. When a tank is refilled, particularly if it has been allowed to run very low or empty, that balance can be disturbed.
Air can enter the pipework, pressure levels can change suddenly and safety devices within the system may activate as a precaution. Your heater, which depends on consistent gas flow, may then struggle to ignite or shut down entirely.
From the outside, it looks like a heater failure. In reality, the issue is often somewhere between the tank and the appliance.
Air in the system
One of the most common causes is air trapped in the pipework. If the tank was close to empty before delivery, air can be drawn into the system and sit in the pipe line.
Your heater cannot burn air, so even though gas is present, the mixture is not correct for ignition.
This often shows up as the heater clicking or attempting to start without producing a flame, or firing briefly and then cutting out. If a line has completely run dry then the chances of a heater self-purging is only likely if it’s a very short pipe run with minimal changes in direction. Otherwise, an engineer would visit site and manually purge the line to get everything up and running again.
Why safety devices can stop the system working
Modern LPG systems are designed with safety in mind. Regulators, shut-off valves, and UPSOs / OPSOs (under & over pressure shut offs) are all there to protect the system if something unusual happens.
A fuel delivery can create exactly the kind of sudden pressure change these devices are designed to react to. As a result, they may temporarily restrict or completely stop the flow of gas.
When that happens, your heater will not receive enough fuel to operate, even though the tank is full.
Regulator and Valve issues
The regulator plays a key role in controlling gas pressure. If it is worn, damaged or affected by the refill process, it may not deliver gas at the correct rate.
Similarly, an UPSO or an OPSO may trigger if it detects a rapid change in the flow of gas, effectively shutting things down until the system stabilises.
In some cases, simply turning the system off, waiting briefly, and reopening the supply slowly can resolve the issue. In others, the regulator may need inspection or replacement.
When its not related to the delivery
It is also worth considering timing. Not every post-delivery problem is caused by the delivery itself. Components such as regulators, ignition assemblies or valves can fail independently and it can just happen to coincide with a refill.
If the system was already showing signs of inconsistency, the delivery may simply highlight an underlying issue rather than create one.
When it’s more than a simple reset
Many post-delivery issues can be resolved with basic checks, but not all of them. If the heater continues to lock out, fails to ignite consistently or shows signs of poor performance, the system should be inspected by an engineer.
Gas pressure, component condition and overall system setup all need to be considered.
Book your free site survey
If your warehouse or workplace is not reaching a comfortable temperature — or if your heating bills feel disproportionate to the warmth you are getting — a site survey is the fastest way to get a clear, honest answer.
Contact Harry Taylor to arrange yours. We work across the full UK mainland from offices in both the North and South of England, and there is no charge for the survey itself.
Call us: see harrytaylor.co.uk for contact details
About Harry Taylor
Harry Taylor has been designing, installing, and maintaining heating systems for factories, workshops, warehouses, garages, and retail spaces since 1925. With offices in both the North and South of England, we cover the full UK mainland. We work closely with every client to ensure the right solution — whether that means a new installation, a system upgrade, or simply better maintenance of what is already there.