Pumping domestic hot.....

[Ookysoft]

Ok, I tried to ask this before - I'm now off the tablets so hopefully I'm more coherent!

I have a friend who want to pump his hot water.
He has a pump which can be installed at his hot water cylinder.
The current pipework is gravity fed.
If he just pumps it as it stands, He'll **** water out through the vent in the loft, back into the supply tank.

So... is there a gizmo to put at the top of the pipework to seal the system [from pump to vent & all the hot taps inbetween] but allow trapped air out.

This is assuming that allowing the feed tank to 'take back' any expansion in the cylinder, is acceptable?

I kinda know there maybe a suitable automatic airvent where there is little or no pressure but will it work ok under 1.5bar pressure?

Is this an acceptable solution?

 

[Rob]

If the Open vent and hw pipes are installed correctly then no it wont **** out. There should be more of a risk of drawing air in!

You dont run an open vent to the loft teeing off on the way

 

[gas4you]

You're not allowed any form of restriction in the open vnt. If the pump is fitted after the vent is teed off then it cannot pump over, only out of the taps. As Rob says more likely to suck in air, that is why they should be fitted to a surrey or an essex flange on the cylinder.

 

[ChrisR]

You two have misread I think - the OP want to pump his DOMESTIC hw!
But thinks you pump the water INTO the cylinder. You don't, normally, you pump it FROM the cyl.

This is a typical arrangement, shown for a shower, except ignore the sloping pipe and use a flange on the cylinder for the HW supply:

 

[gas4you]

No that is exactly as I read it Is not my description the same as your diagram Chris??

 

[ChrisR]

Sorry that's twice. I need to read more carefully

 

[Ookysoft]

Hmmm!

Having inspected the pipework whilst doing an exstensive refit of the bathroom, the installer has DEFFO Tee'd all the hot water outlets off of the same pipe which vents over the header tank in the loft.

So, out of the top of the cylinder, to a Tee to the kitchen, onward to the bathroom & onward to the loft.

I gather from the replies, that conventionally there should be a vent pipe from the top of the cylinder & the supply [to domestic outlets] Tee'd from that.

 

[chrishutt]

the installer has Tee'd all the hot water outlets off of the same pipe which vents over the header tank in the loft. So, out of the top of the cylinder, to a Tee to the kitchen, onward to the bathroom & onward to the loft.

Nothing wrong with that, providing the vent pipe keeps rising towards the tank. but it does make it difficult to add a pump. You'd have to run a new, separate pipe, either to vent or to supply the hot outlets, by the sound of it.

 

[Ookysoft]

That's what I was afraid of - it's very impractical to do that in this house!

Hence asking if there was an automatic valve I could pop onto the vent to let the rising air out, You get them on central heating systems but this thing will probably be at 1.5bar pressure [ as he already has a spare pump ]

 

[chrishutt]

No way can you put anything on the open vent. It's an important safety device. You might want to consider going for an unvented (mains pressure) cylinder, in which case you might not need a pump anyway, although it could be fed from a tank via a pump.