Just received my new water heater today....

[nedb]

(06-08-2013 16:58)nedb Wrote:  Blimey. IsoTherm's recommended solution is to convert the "male" BSP fitting to "female" with a $15 bronze adapter from McMaster-Carr, then attach my plumbing with an NPT male + Loctite 577 thread sealer pa

IsoTherm really does make nice looking water heaters. I'll order the adapter and thread sealer, and reinstall the mixer once I get the plumbing sorted out. Hot Diggity!

So. I got the BSPP-to-NPT adapter and compared it to the factory-supplied outlet on the mixing valve. The BSPP threads on the mixing valve should look different from NPT. As I've learned more recently, BSPP fittings do not seal like NPT threads, they require a steel and rubber washer at the base to seal, whereas NPT are tapered to seal tightly against each other as the fitting is tightened. That bit of info makes interpreting the following pictures pretty simple--the stainless is the NPT end of the adapter, and the brass is the mixing valve outlet ("BSPP").




Obviously, these are both identical tapered threads, no BSPP here. So I installed it without the adapter, sealed the threads with the Locktite, and it is all good.

Some older stock in warehouses could still have BSPP threads, but this one arrived without thread issues. At some point, they were apparently shipping the water heaters with an adapter for BSPP-to-NPT, but nothing like that was included in the box I received.

I didn't have to make any special request, this is just what they sent.

IsoTherm (aka Indel) ought to pump this info onto the web so that shoppers can buy with more confidence. The prospect of added time and cost for getting an adapter would drive some customers away.