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4"DCC Road Loco Hydraulic test

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4"DCC Road Loco Hydraulic test Empty 4"DCC Road Loco Hydraulic test

Post  andyfletch Mon 27 Sep 2021, 8:42 am

As I have only steamed my engine at home since completion, I have not had it tested at my club.

I went to the club last week and everyone seems to have an different opinion on what I should do to set it up for a Hydraulic test.

On my previous Agricultural engine I plugged the 2 ports in the top of the cylinder and fitted a hand pump via left hand clack valve, which worked well.

Reading an article for 2016 on this forum, others have placed a rubber seal under the puck and used the safety valve to keep the puck water tight. A club member boiler inspector also told me not to use my supplied pressure gauge as the higher pressures involved in testing could damage it.

so I am after a difinitive process. Questions I have

Do I need to take the safety's off and block the regulator port? if so how have people done this,
Do i need a separate test pressure gauge and if so where do i fit it
where's the best place to attach the hand water pump ( there is a gauge on this but not sure how accurate this is)
any other blanking or preparation needed
is the first hydraulic test done at a higher pressure than ongoing tests (from memory I think the test is at 1 and a half times working pressure. so on my engine with 180 psi, it should be tested to 270psi??

Thanks in advance


Number of posts : 76
Location : Great Dunmow, Essex
Registration date : 2008-06-21

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4"DCC Road Loco Hydraulic test Empty Re: 4"DCC Road Loco Hydraulic test

Post  lynnr Mon 27 Sep 2021, 11:23 am


By virtue of the higher pressure needed for a in service hydraulic test of 150% working pressure.

Your safety valves either need removing or locked down. Removing is simpler and safer.
A sturdy blanking plate for the safety valve opening with a hydraulic fitting installed is the best place to fill and test from.
Depending on your "tightness" of the regulator puck. A rubber gasket will help or using the plate to blank the safety port as a mount use a bolt or stud to firmly press against the regulator puck to hold it down would also work.

You need to remove your in service pressure gauge as it will get damaged by the "over pressure".

To locate a calibrated test pressure gauge. Add a T piece to the blanking plate hydraulic fitting from the test pump tank and have the test gauge hang off that.

Hope this helps

Number of posts : 3230
Age : 53
Location : Highland, 4inch showman
Registration date : 2010-08-06

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