I want to use a stainless steel heat exchanger (intended for a
Vaillant boiler) as a pre-heater as part of converting a diesel
vehicle to svo (straight vegetable oil).

So I need hose tails to couple between the threaded flanges on the
heat-exch and the fuel and coolant hoses on the vehicle.

I've been through my box of plumbing bits, and found the following
matches:

2 (male) threads on the heat-exch match the nut used on 15mm
compression fittings
2 (male) threads on the heat-exch match washing machine hose couplings

Now I need to look these up in a catalogue to buy hose tails - what
are these 2 sizes called please?

On Sat, 04 Aug 2007 11:51:25 -0000, "
mused:

I want to use a stainless steel heat exchanger (intended for a
Vaillant boiler) as a pre-heater as part of converting a diesel
vehicle to svo (straight vegetable oil).

So I need hose tails to couple between the threaded flanges on the
heat-exch and the fuel and coolant hoses on the vehicle.

I've been through my box of plumbing bits, and found the following
matches:

2 (male) threads on the heat-exch match the nut used on 15mm
compression fittings
2 (male) threads on the heat-exch match washing machine hose couplings

Now I need to look these up in a catalogue to buy hose tails - what
are these 2 sizes called please?

1/2" and 3/4" BSP.
--
Regards,
Stuart.

1/2" and 3/4" BSP.

Cool - thanks!

I kind of vaguely recalled they were - but doubted myself.

Are they defined by the OD size of the pipe they're usually used with
- as 1/2" and 3/4" doesn't seem to relate to any dimension on the
threads themselves?

wrote:

Are they defined by the OD size of the pipe they're usually used with
- as 1/2" and 3/4" doesn't seem to relate to any dimension on the
threads themselves?

Defined by the inside diameter of the pipe they were traditionally used
with IIRC.

--
Cheers,

John.

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The message
from John Rumm contains these words:

Are they defined by the OD size of the pipe they're usually used with
- as 1/2" and 3/4" doesn't seem to relate to any dimension on the
threads themselves?

Defined by the inside diameter of the pipe they were traditionally used
with IIRC.

I think that was thick walled iron pipe.

1/2" and 3/4" BSP both have 1.814mm pitch (14 threads per inch) and
major diameters of 20.445mm and 26.441mm respectively.

--
Roger Chapman