No bypass equels pumping over sucking in air!! equels corrosion 
is the tank high up??
is the tank high up??
Manky Gunk in F/E Tank!
- Thread starter Schmill
- Start date
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"Pumping over" ?
Well, it's high up as in it is in the loft, so effectively the floor above the airing cupboard. However it's not 'high up' in the loft, as the pitch of the roof isn't particularly high. It is sat on a platform built up from the floor that holds it and the large water storage tank that feeds the DHW supply.
I suppose the bottom of the FE tank is maybe 1' above the floor level of the loft at most.
Well, it's high up as in it is in the loft, so effectively the floor above the airing cupboard. However it's not 'high up' in the loft, as the pitch of the roof isn't particularly high. It is sat on a platform built up from the floor that holds it and the large water storage tank that feeds the DHW supply.
I suppose the bottom of the FE tank is maybe 1' above the floor level of the loft at most.
Sorry, just looked up 'pumping over' and I don't think that is what is happening. I never saw any water coming OUT of the vent pipe. If anything I would call it 'pumping under', in that it seems to prefer to suck air in through the VENT pipe, rather than using the cold water from the cold fill pipe.
When your demand drops off ie central heating & hot water turn off you may get a surge of water up the open vent as the water has no where to go, this will be very brief tho as the voltage drops off the pump.
causing water to re enter the cental heating system (which will have oxygen in the water) causing corrosion/sludge
causing water to re enter the cental heating system (which will have oxygen in the water) causing corrosion/sludge
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Oh I see what you mean, so water is racing round the system at high speed, then the valves close and the pump stops, but obviously the water doesn't stop immediately, and hence would shoot up the vent pipe into the tank, whilst at the same time water from the tank would going down the fill pipe to replace it?
I was by the vent pipe in the loft whilst my wife switched the pump on and off several times and no water seemed to come from the vent pipe. Also, although the FE tank is situated at nearly loft-floor level, the Vent pipe rises all the way to the rafters before then arching over and down to the FE tank.
So from all the aobve I am pretty sure it is not pumping over. It does seem it might be drawing air in via the vent pipe though. Is there such a thing as a backwards air-admittance valve that could be fitted on the Vent pipe? i.e something that would allow excess water / steam / air to come OUT of the system, but not allow air to be sucked INTO the system via that pipe?
I was by the vent pipe in the loft whilst my wife switched the pump on and off several times and no water seemed to come from the vent pipe. Also, although the FE tank is situated at nearly loft-floor level, the Vent pipe rises all the way to the rafters before then arching over and down to the FE tank.
So from all the aobve I am pretty sure it is not pumping over. It does seem it might be drawing air in via the vent pipe though. Is there such a thing as a backwards air-admittance valve that could be fitted on the Vent pipe? i.e something that would allow excess water / steam / air to come OUT of the system, but not allow air to be sucked INTO the system via that pipe?
yes i agree no pumping over happening, its good to see the open vent going over the tank that high..
You can fit a magnaclean on the flow after the pump.
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