No vent pipe over f + e

[armyash]

Got sent to a job couple of days ago, first time I have had a chance to post about it.

the customer has a few aqualisa showers in the property, up in the loft has the blending/pump type things.

i got sent out because the showers were not switching off, we don't deal with them and Cust said still under warranty do will get aqualisa out.

Water in cwst was hot, customer had left immersion on all night and could hear water going up vent pipe from cylinder.

this stopped once immersion was switched off.

There is no vent pipe over f and e, surely there should be?

the showers now don't switch off, if the electrics are switched off then the power from the showers goes away but they still run unless isolated in the loft.

All sounds a bit random bit anyone have an idea what's going on?

i think the immersion obviously kept heating the water but not sure how this affects the showers and why no vent over f and e.

 

[Leo21]

Do you mean the heating f & e? If it is this is unusual but ok. It was in some of the mi,s, usually for systems with a lack of head height. It stops air being drawn in to the expansion tank. I think it's called wet vent.

 

[plumbdoctor]

Is it not just a combined cold feed and open vent ??

 

[Leo21]

Is it not just a combined cold feed and open vent ??

Not if there's no vent over the tank, no.

 

[armyash]

Is it not just a combined cold feed and open vent ??

No vent over tank.

Just cold in and cold out.

 

[armyash]

Do you mean the heating f & e? If it is this is unusual but ok. It was in some of the mi,s, usually for systems with a lack of head height. It stops air being drawn in to the expansion tank. I think it's called wet vent.

Ok. Could be that, but yes the heating f and e.

 

[rocketmanbkk]

My mums f&e has no vent

She's got a crappy fortic in the airing cupboard

 

[plumbdoctor]

If there's no vent over the top then the supply pipe also takes up the expansion, always called them combined cold feed and open vent, what is it called then ?

 

[Leo21]

A combined cold feed and vent is when the cold feed and vent is teed right by the tank. A wet vent has no open vent, just a 22mm pipe connected into the bottom of the tank.

 

[Leo21]

This is a combined cold fill and vent.

 

[gassafe]

Boiler I went to last week had no vent either, i thought it might air lock etc on re-filling but filled up fine...

 

[plumbdoctor]

What I mean is combined cold feed and vent I thought it was called ? I was tired last night haha

 

[MOSSEP]

On the subject of the pumps continuously running, sounds like maybe a stuck flow switch?

 

[plumbdoctor]

Shower pump ?

 

[bright spark]

I think some systems 'semi sealed' if ye get me off tank in attic. Cold fed has non return valve fitted and system is fitted with expansion vessel too. So no need for open vent.

 

[JCSPLUMBING]

Wet vent. Stops air being drawn in. I find them a better option sometimes.

 

[BLOD]

The older (grey) Aqualisa digital shower has a solenoid shut off valve that can fail. This can get stuck in gthe open position allowing constant flow of water.