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How to use a gas greenhouse heater safely

Updated: 22 October 2026

You have a propane cylinder, a heater from the [gas greenhouse heater comparison](/hub/heating/gas-greenhouse-heater), and a cold forecast. The failure mode is familiar: connect quickly, light, then wonder why the pilot dies or why the glass steams up. This page is the sequence for the unflued blowers in that set: regulator match, leak test, ventilation before flame, shut-down, and when to stop. It does not rank models. Peter F. follows UK propane practice from Flogas and manufacturer manuals. Always read the booklet for your exact ASIN. A qualifying purchase can earn a commission at no extra cost to you.

You have a propane cylinder, a heater from the gas greenhouse heater comparison, and a cold forecast.

Our top picks

Bimson Power Bimson Power 15 kW

Best overall

Bimson Power Bimson Power 15 kW
9.4/10about £119.99
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DAHTEC DAHTEC 10 kW

Rank 2

DAHTEC DAHTEC 10 kW
9.4/10about £219.00
View offer
Bimson Power Bimson Power 30 kW

Rank 3

Bimson Power Bimson Power 30 kW
0.0/10about £169.99
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On this page
  1. 1.Read the pressure on the heater
  2. 2.Connect and leak-test
  3. 3.Open air, then light
  4. 4.Shut down and when to stop

Read the pressure on the heater

UK frost heaters often use a low-pressure propane regulator around 37 mbar, cylinder upright, hose matched to the data plate. That is the Eden-class world in the propane greenhouse heater buying guide, not a rule for every amazon.co.uk listing. The Bimson operator manual prints about 300 mbar on the 15 kW BP-G15T line and about 700 mbar on the BP-G35T family used for the 30 kW listing. Flogas is explicit that high-pressure and low-pressure regulators are different devices. A spare 37 mbar part mismatches the burner. The DAHTEC listing describes piezo ignition, a separate gas valve, a thermocouple and an 18 V battery fan. The Bimson listings describe spark ignition and a 13 A plug. None of the three names an oxygen depletion sensor. Replace a hose or regulator with the same pressure class.

Connect and leak-test

Stand the cylinder upright on a stable base, outdoors or somewhere well ventilated, not inside a shut glasshouse. The UK POL fitting tightens left-hand. Nip it with a spanner as Flogas describes, without cracking the fitting. Connect the regulator and hose to the cylinder first, then to the heater, in the manual’s order. Open the cylinder valve only when the manual says to, with the appliance valve off if that is the check. Brush soapy water on every joint after gas is in the line and before you light. Bubbles mean stop, tighten once, and retest. If they persist, replace the regulator. Do not hunt leaks with a match, and do not light in a closed house to see if it smells. A strong smell of gas means valve off, ventilate, and 0800 111 999 from outside if you suspect a continuing leak.
Bimson Power Bimson Power 15 kW

Testsieger

Bimson Power Bimson Power 15 kW
9.4/10about £119.99
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Open air, then light

Open a door, a ridge vent, or a low-level airway before you light an unflued heater. Hotbox ties soot and a dying flame to lack of air. Closing every vent is the wrong fix. On an Eden-class heater, an oxygen-depletion trip is a shutdown when the lower house is starved of air, not a fault to bypass. None of these three names that device. The same physics still applies. Stand clear of the intake and outlet. On the DAHTEC, follow piezo, gas valve and battery fan. On the Bimson, spark and the mains fan on a suitable 13 A socket. A yellow or lazy flame, roaring, or soot means stop, ventilate, and clean or service. If the flame dies within minutes, check vents, a blocked fan intake, and the supplied regulator before you try again.

Shut down and when to stop

Turn the gas off at the cylinder valve first, then the appliance valve and fan as the manual states. Let the unit cool before you move or cover it. Store it so insects cannot block the burner. Hotbox warns that blocked ports change the flame. Do not relight without professional help if soap keeps bubbling after a regulator swap, the burner stays sooty or noisy, anyone nearby has carbon monoxide symptoms, or the heater was knocked over while hot. A thermocouple or overheat cut-out that trips again is a message, not a button to override. Symptoms and the numbers to call are on carbon monoxide greenhouse heater ventilation. These blowers are not camping stoves in a tent or a sealed propagation box. The NHS warning about enclosed spaces applies to people, and a glasshouse with every vent shut is the same class of mistake.

Common questions

In what order do I connect the cylinder?
Upright cylinder, the regulator that matches the data plate, hose to the heater, POL tightened left-hand, appliance off, and the cylinder valve on only when the manual allows a test. Soap-test the joints, then move the heater and ventilate. Lighting order differs between DAHTEC and Bimson, so use that booklet.
How do I leak-test without a flame?
Brush soapy water on the cylinder neck, regulator and hose tails once gas is in the line. Growing bubbles mean stop. Tighten once and retest. If bubbles remain, replace the regulator. Matches, lighters and a sniff are not a test.
Why does the heater go out after a few minutes?
Often too little combustion air, a regulator fault, or a safety device doing its job. Open the vents, confirm the Bimson fan has mains or the DAHTEC fan has battery, and look for soot. Do not disable the cut-out, and do not seal the house to hold the flame.
Can I use a barbecue regulator?
Not on a Bimson whose manual specifies 300 mbar or 700 mbar. High-pressure and low-pressure regulators are different parts. A barbecue regulator belongs only on a heater whose data plate says low-pressure propane and whose regulator matches that label.
What do I turn off first when I finish?
The cylinder valve first, then the appliance controls as the manual states, then fan power if the booklet says to isolate it. Let the heater cool before you move or cover it. Store it so insects cannot block the burner ports.

Related pages

Best gas greenhouse heater UK

Gas greenhouse heater

Propane greenhouse heater size for a UK glasshouse

Carbon monoxide greenhouse heater: vents and alarms

Gas vs electric greenhouse heater for UK hobby plots

Sources

Public UK sources named below. amazon.co.uk prices, stars and review counts on these three listings were taken from the listing files read on 20 October 2026. Page updated October 2026.

  1. RHS, heating greenhouses efficiently (retrieved 20 October 2026)
  2. Gas Safety (Installation and Use) Regulations 1998 (retrieved 20 October 2026)
  3. HSE domestic gas FAQ (retrieved 20 October 2026)
  4. HSE gas safety for employers (retrieved 20 October 2026)
  5. GOV.UK carbon monoxide (retrieved 20 October 2026)
  6. NHS carbon monoxide poisoning (retrieved 20 October 2026)
  7. London Fire Brigade carbon monoxide safety (retrieved 20 October 2026)
  8. Liquid Gas UK Consumer Guidance Sheet 39 (retrieved 20 October 2026)