Oil Tank - fitting a Watchman Alarm ?

[Rollerball]

I purchased a Watchman Alarm a few days ago to fit to my oil tank.

My oil tank already has a pre-drilled hole with a sticker besides it saying 'Watchman Alarm' - unfortunately the hole is only 25mm wide so I would need to purchase a suitable 32mm hole-saw and make it larger.

That's not a major problem, what concerns me is that the part of the tank where the pre-drilled hole is located is on a very slight curve (if I rest a level ruler on that surface that's the diameter of the alarm then the ruler has about a 1mm or 2mm gap under each far edge of the alarm diameter). This would cause a problem fitting the washer and the alarm - if the base is screwed down tight then the lower part of the alarm fitting will bent slightly and the main alarm unit won't screw in correctly (I haven't tried this, I'm basing this on assumption).

The only suitable flat surface that I can see is the large 'bulges' that can be seen on most tanks - the plastic 'ribbing' if you like. The trouble is that these are higher than the fill point (not 'allowed' according to the Watchman instructions) and, due to their height, I'm not sure if the signal from the detector will reach into the tank correctly.

What can I do, if anything?


Thanks

 

[leakydave]

I would put it where the manufacrurer intended it to go...

The watchman Instructions say something like "If in doubt where to drill your tank ask the manufacturer" and they are bound to say 'where the hole fir it is'.

Remember to set the height of the tank using the dip switches on the receiver.

 

[Rollerball]

Thanks, will do. Just had to order a 32mm hole-saw to make the existing hole bigger.

 

[djsarge1973]

Just be careful when using a 32mm holesaw asit'll have NO pilot hole so the blade will "bounce" around, little tip, rest the hole saw over the hole that you want to enlarge, mark around it with a permenant marker then twist the holesaw with your hand until it scores the plastic, then use the cordless drill on a slowest speed as possible, & dont WORRY if the plastic cut out falls in the tank it'll just float ontop of the Kerosene

 

[Rollerball]

Many thanks for the advice, I appreciate it.

 

[electronicsuk]

Worth noting that if you have a 25mm holesaw, you may (depending on the amount of thread available) be able to screw both 25 and 32mm saws onto one arbor at the same time, which will give you something to guide the drill into the existing hole.

 

[Rollerball]

Afraid that I only have a 32mm holesaw.

 

[SpecialK]

Drill a 32mm hole in a sheet of wood first, then place this wood over the tank and drill again.

 

[Burnerman]

Good post that....
Or buy an Apollo and get in some practice sending it back
John

 

[Rollerball]

Drill a 32mm hole in a sheet of wood first, then place this wood over the tank and drill again.

That IS a good idea, I like that.