Bro had a couple of these fitted last year to boost the hot and cold gravity flows in his flat. They were chosen to be a gentle boost as they add a very useful 0.5 to 0.75 extra bar (to a gravity system which is barely 0.2 bar), and are very quiet in use.
They worked a treat, although the cold one would sometimes be unreliable in firing up automatically, but when they did work they gave a great shower.
A few days ago a burst water mains in the street meant loss of mains water for a day, so the CWS tank ran dry. The 'cold' Grundfos responded by burning up... Searingly hot, and nasty electrical burning smell.
Bro called plumber out who was not familiar with these pumps but looked up the install instructions; they have both been fitted incorrectly. They must pump upwards, so whatever the pipe run, they must be fitted where there's an upwards vertical pipe. They also need to be fitted where there's a min 2m 'head'.
The cold, however, was fitted almost immediately out of the CWS and was pumping downwards. The hot was marginally better as it was fitted low to the flat's floor, but it too was fitted on the vertical downwards-flowing hot outlet from the cylinder.
This explained why the cold pump kept on running when it was dry - the flow switch was likely affected by gravity.
Ok, the question! Currently there is no single point on either the hot or cold supplies which are flowing upwards where the pumps can be fitted correctly. The only places are where the individual pipes come up from the floor to the actual taps, but that would require 6 pumps so clearly ain't going to happen!
The only solution I can think of - but is not ideal on a gravity-fed system - is to have the hot and cold supplies coming down to the floor before being swept-bend horizontally along the floor a short distance before then being s-b upwards where the pumps can be fitted before then s-b back down below the floor and off to the bathrooms; ie this would allow the fitting of the pumps on the upwards part of an upside-down 'U' shape of pipework.
If there's any mileage in this idea, then an auto air vent at the top of each 'loop' would probably make sense?
Is this crazy? Is there any other solution that would allow the use of these pumps - he doesn't want a more powerful pump that would almost certainly be noisier (thinking more of the flat below).
Thanks.
They worked a treat, although the cold one would sometimes be unreliable in firing up automatically, but when they did work they gave a great shower.
A few days ago a burst water mains in the street meant loss of mains water for a day, so the CWS tank ran dry. The 'cold' Grundfos responded by burning up... Searingly hot, and nasty electrical burning smell.
Bro called plumber out who was not familiar with these pumps but looked up the install instructions; they have both been fitted incorrectly. They must pump upwards, so whatever the pipe run, they must be fitted where there's an upwards vertical pipe. They also need to be fitted where there's a min 2m 'head'.
The cold, however, was fitted almost immediately out of the CWS and was pumping downwards. The hot was marginally better as it was fitted low to the flat's floor, but it too was fitted on the vertical downwards-flowing hot outlet from the cylinder.
This explained why the cold pump kept on running when it was dry - the flow switch was likely affected by gravity.
Ok, the question! Currently there is no single point on either the hot or cold supplies which are flowing upwards where the pumps can be fitted correctly. The only places are where the individual pipes come up from the floor to the actual taps, but that would require 6 pumps so clearly ain't going to happen!
The only solution I can think of - but is not ideal on a gravity-fed system - is to have the hot and cold supplies coming down to the floor before being swept-bend horizontally along the floor a short distance before then being s-b upwards where the pumps can be fitted before then s-b back down below the floor and off to the bathrooms; ie this would allow the fitting of the pumps on the upwards part of an upside-down 'U' shape of pipework.
If there's any mileage in this idea, then an auto air vent at the top of each 'loop' would probably make sense?
Is this crazy? Is there any other solution that would allow the use of these pumps - he doesn't want a more powerful pump that would almost certainly be noisier (thinking more of the flat below).
Thanks.
