MDPE to dual outdoor tap

[DaveHkent]

Looking for some advice, for what has turned out to be a really frustrating afternoon!

I have some 25mm MDPE pipe buried up the length of the garden and want a tap up the top end to save all the trips up and down the garden with watering cans during these hosepipe bans. The old tap was leaking anyway, so I replaced with a dual tap with a check valve. One of these:

https://www.amazon.co.uk/dp/B0CP652Q9C?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1&th=1

My plan was to use the longer tap as a normal tap and connect the MDPE to the lower tap, which has a 3/4" thread. That will allow me to shut it off and disconnect in the winter to stop it freezing and bursting the pipe.

I got a Flomasta 25mm MDPE to 3/4" BSP:

https://www.screwfix.com/p/flomasta-mdpe-female-adaptor-25mm-x-3-4-/627cv

It doesn't fit. It is so close, but the thread must be slightly different. I forced the first one, knackered the thread, it went on cockeyed and as you can imagine, didn't make a watertight seal. Picked up another and I can see it going the same way. I have tried screwing it onto the old tap to, to make sure it is not just the thread on the new tap, and the screw just doesn't engage. It looks like whatever the plastic female screw thread is, is different to the standard outdoor tap thread. A 3/4" hose adapter goes on it without a problem.

So what do I need to link the two together? Typically it has got to the stage on a Saturday evening where all the local plumbing merchants are closed until Monday.

 

[jj4091]

There are different types of thread.
Common 3/4-Inch Thread Types

• • BSP (British Standard Pipe): Standard across the UK, Europe, and Australia. It uses a 55° thread angle (Whitworth form) and comes in parallel (BSPP / G-thread) or tapered (BSPT). Parallel versions rely on an O-ring or flat washer to seal.
  • NPT / NPS (National Pipe Tapered / Straight): Standard across North America. It uses a 60° thread angle (Sellers form) with flattened peaks and valleys. NPT is tapered and wedges tight, while NPS is straight.
  • GHT (Garden Hose Thread): Common on outdoor hoses and spigots. A 3/4" GHT connector is straight and uses a flat internal rubber washer to seal against the mating rim, meaning it will cross-thread or leak if screwed into a 3/4" NPT or BSP pipe fitting. [1]

Possibly bsp on the mdpe pipe and ght on the tap. Take the hose connector to a plumbers merchant and get a ght male to bsp femal converter. And check it fits your connector

 

[DaveHkent]

Thanks. I got one that looks the same, but has a different thread and appears to work.