At a recent club meeting I was asked to write something about preparing boilers for testing. Well, there are three states in the testing of boilers, the first - new build, the second - boiler not mounted and thirdly, the boiler mounted as in a traction engine or in a loco .

With the first state and where the boiler has been made by a reputable manufacturer, then it will have documentation for the proof test with it and the only tests it will then need are those that the clubs insurance require. If, on the other hand, the boiler has been built by someone not approved by an insurance company, then it will have to be proof tested by the club's inspectors. Every boiler must be steamed for a safety valve check by the club's inspectors even if has been commercially built.

This means that the owner must provide for himself, a set of plugs and blanks for all openings in the boiler with one screwed 5/16” x32 tpi male for the test connection and if possible one to act as an air release point fitted to the highest point on the boiler.

If the owner has a hand pump or a test pump available it would save time at the official test if he pumped the boiler up to working pressure prior to presenting it for the official test, so that he knew that it was tight and that none of the blanks leaked. If the boiler holds at working pressure, then it would be unlikely to leak at proof test pressure.

In the case of the mounted or unmounted boilers as in test boilers or locos, all of the above are still required but in addition provision must be made for gagging the safety valves and blanking off the steam pipework if the regulator is unable to hold at test pressure. Some gauge glasses may cause problems and plugcocks are virtually guaranteed to leak even if they hold at working pressure. Forgetting to remove or blank off pressure gauges also tends to be fatal and it is unwise to rely on a plugcock to hold against proof test pressure. Much safer to remove the gauge and plug the line.

The club's boiler Inspectors are at liberty to ask for the boiler cladding to be removed prior to a hydraulic test if they see fit and in the case of a boiler of unknown provenance, perhaps recently introduced to the club, then they should not hesitate to do so if they think it is in the best interest of the Club.

The steam test is an annual event to prove that the safety valve will hold the boiler pressure at less than 10% above working pressure, fully fired and with the blower on.

All boiler owners should provide themselves with their own test pump and gauge if they are able. The pump can double as a hand pump for filling and need not be anything very sophisticated. Mine is an L.B.S.C. axle pump casting and has pumped up to 600 p.s i. - far more than anything we would normally need.

We often hear the experts talking about the "de-zincification" of brass in boiler fittings and dreadful tales about fittings crumbling away. But remember this, those boilers which are blown down after every session and stored dry are for all practical purposes immune to the problem You do not see that white deposit round the fittings on a dry-stored boiler.

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