The subject of gas inspections comes up very often on all the ex-pat forums.
Real Decreto 919/2006 covers the law about LPG use. Reproduced below.
If you need a 5 year inspection call Repsol on 901 100 100 and have it done properly.
The inspection should cost in the region of €60.
CLICK IMAGE TO ENLARGE IT
Approximate part translation of this:
The owners or users of gas supplies, not fed from the mains, are responsible to order a periodical inspection by a gas installation company authorised in accordance with ITC-ICG09. Said inspection is done every 5 years.
For installations using pressures less than 5 Bar the items checked are: the state of the container(s), good care and state of the contents, safe combustion on the apparatus installed, and correct extraction/ventilation of burnt gases.
All of this is for our own safety
2. Gas inspection companies touting for business will visit houses. You do not have to let them in. Their usual modus operandi is to knock the door, show a certificate from the Town Hall, or other papers, which may show that they are a genuine company. However, they have been known to make false claims, for instance, stating that regulators are out of date, (they either work or they do not). They replace tubes and regulators charging extortionate fees (I have heard of €400 being paid!).
The shop price of a regulator is about €10 and the orange gas pipe is a couple of €uros per metre.
Beware of bogus gas inspectors in Spain!
NEVER ALLOW A GAS COMPANY CALLING “ON SPEC” INTO YOUR HOUSE.
This helpful video shows how to change a Repsol gas bottle. Don’t be put off that it is Spanish. The main things to note are the lifting of the collar on the regulator and the valve on the top being turned off before fitting onto the new bottle, then pressing firmly down on the collar until it clicks into position. These are clearly shown in this video.