Shower pump - no flange

I just had a shower pump installed.

The plumber didn't fit a Surrey flange but rather used a weld T joint from the hot water tank main supply pipe.

I know most pump manufacturers advise or require a flange. I assume this is for warranty purposes. Oddly, Aqualisa, on its power showers doesn't advise use of a flange.

Anyway, the T joint is a vertical drop from the main supply pipe at a point where the main supply point is perfectly horizontal.

My poor knowledge of physics tells me that there is little if any chance of air getting in to the pump supply because the water supply to the pump is a straight vertical drop from a straight horizontal supply pipe.

Is this correct?

I'm not confident enough to want to undertake a DIY flange installation and pip re-routing so I'm hoping the answer is that, possibly aside from strict warranty clauses, a flange isn't necessary in these circumstances.

Reply to
Gazza
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In message , Gazza writes

They tried that here:-(

Came back and fitted the proper flange job. I think it depends on the draw off rate and the ability of the supply to maintain a positive head.

In our case, upstairs shower and HW cylinder with header mounted on loft floor joists, it didn't work.

Still get interesting air locks but for other reasons (I think).

Reply to
Tim Lamb

In message , Gazza

Our two shower pump is plumbed from the 21mm bath supply and works perfectly, even with two showers going at once.

Mike

Reply to
Muddymike

Less to do with the warranty than the fact that if the pump sucks faster that the cold feed to the HW tank it will draw air through the tank vent. You may get away with it depending on your pipe layout and adequacy of tank filling. It really is a case of "suck it and see".

If it does sound like its sucking any air, you're justified in getting the plumber back to "do it properly".

Tim

Reply to
Tim+

The need for a flange is really dictated by circumstance - pipework layout, and the power of the pump.

No not really. Air can accumulate in the cylinder due to it coming out of suspension in the water when its heated. Also its possible that if the pump sucks hard enough, it will attempt to draw water faster than the cold cistern can replenish the cylinder, then air will be drawn in from the vent pipe directly.

If it works reliably and the shower does not splutter or pause etc due to air ingress, then there is nothing to worry about.

(for what its worth, adding a surrey or warwix flange is relatively easy and does not require many pipework changes)

IME pumps up to 1.8 bar are normally ok on a normal feed if the pipework is not too convoluted.

Reply to
John Rumm

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