Extra 22mm boss on HWC, can I use it for shower pump?

[Servotech]

Thanks for the replies all. I looked at the manufacturer instructions and it says either top or side, but does recommend a short length dip pipe like simond advised to get away from any bubbles of air in the HWC.

Yep Ben, that sounds like the one, it's a stainless one. How long have you been running it in that way? I understand air is not great for pumps, but sounds like you haven't had any issues?

Thanks for the reply servotech, I think you're right, filing the lip isn't very smart. But the "birdsmouth" and dip pipe do make sense, albeit how much effect that amount of air actually has in practice I don't know. I've attached the manufacturer's recommendation below.

Thanks dilalio; I found the installation guide rather than call the number but it looks quite explicit in there.

View attachment 87159

I think I'm left with this decision:
1) Use a Surrey flange from the top and blank the side boss
2) File away the lip at risk of compromising the integrity and warranty of the cylinder
3) Don't use a dip tube and plumb straight from the side boss and compromise the warranty of the pump

As much as I'd love to take advantage of the side boss, it seems it would be silly to risk blowing the warranty (or worse the integrity) of the HWC and pump.

Thanks a lot for the replies though, really appreciate people taking time to help on these forums.

Cheers,

Simon

The manufacturers are not plumbers and often go off on a whim about something of very little consequence to the plumbing trade.
The thing that is more important is the size of your supply tank above.
A power shower running full bore can empty quite a large one (hot and cold are being drawn off at the same time) in no time at all (then the pump will be sucking in a serious amount of air).
servotech,

 

[Agile]

Quite so, but I cannot see any benefit of a dip tube mounted horizontally at the side port!

Tony