Secondary return with an already pumped system.
- Thread starter BW2
- Start date
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when you two have finished **** between yourselfs
lets go back to the original problem.
if you start with a header in the loft above the height of the loft bathroom, then feed into the hot water cylinder located say on the first floor with a single check valve to stop backflow.
you then have a surrey flange fitted using the side takeoff for the return of your circuit .
at the same time bringing down a cold feed as well
you now have 2 flow (hot and cold) and 1 hot return from cylinder to loft bathroom
with a bronze circulator pump in the hot return
flow pipes now enters pump which has enough water (remember header position) and that then pumps water to bathroom taps
any reason this won't work ?
Yes Kevin that's exactly what you have to do, although if the storage tank is say 600mm above the secondary loop, raising the storage shouldn't be necessary, the check valve on the cold feed to the cylinder definitely isn't wanted.
It doesn't matter what you say or think.
At some time you are pumping water at up to 3bar into an copper cylinder, without the necessary safety devices, I should add.
I stand by what I said Bloody dangerous.
Then you suggest sticking valves on the flow, Great it gets worse, Running the pump for 45 seconds is amply in most domestic premices in your experience.
I don't think the OP will get very wet, if the booster is only running for 45 secs.
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You said it twice.
And I say again, you cannot install a booster pump that returns into a standard copper cylinder.
Now go to bed, I'm begining to think you're Dr Drivel reincarnated. although I don't for one minute think even he is that stupid.
when you two have finished **** between yourselfs
lets go back to the original problem.
if you start with a header in the loft above the height of the loft bathroom, then feed into the hot water cylinder located say on the first floor with a single check valve to stop backflow.
you then have a surrey flange fitted using the side takeoff for the return of your circuit .
at the same time bringing down a cold feed as well
you now have 2 flow (hot and cold) and 1 hot return from cylinder to loft bathroom
with a bronze circulator pump in the hot return
flow pipes now enters pump which has enough water (remember header position) and that then pumps water to bathroom taps
any reason this won't work ?
Yes Kevin that's exactly what you have to do, although if the storage tank is say 600mm above the secondary loop, raising the storage shouldn't be necessary, the check valve on the cold feed to the cylinder definitely isn't wanted.
the reasoning for the single check valve was to prevent any backflow from cylinder to header tank when circulator is running but water demand is satisfied - it is fairly unlikely that it would (cylinder would have to be very very very hot!) maybe a bit too belt and braces
when you two have finished **** between yourselfs
lets go back to the original problem.
if you start with a header in the loft above the height of the loft bathroom, then feed into the hot water cylinder located say on the first floor with a single check valve to stop backflow.
you then have a surrey flange fitted using the side takeoff for the return of your circuit .
at the same time bringing down a cold feed as well
you now have 2 flow (hot and cold) and 1 hot return from cylinder to loft bathroom
with a bronze circulator pump in the hot return
flow pipes now enters pump which has enough water (remember header position) and that then pumps water to bathroom taps
any reason this won't work ?
Where is the suction port of the bronze pump fed from with this arrangement?
T'd off from which pipe?
No Norcon I'm not and nether is Keven.
You run a normal secondary circuit with a bronze pump and check valve to stop back flow when an outlet is opened.
For what it's worth it could be on the same floor as the cylinder, and taken somewhere handy to where the bathroom in question is, say 2.5m in the room below for example.
The pump is fed from the secondary circuit.
Simple and safe.
You run a normal secondary circuit with a bronze pump and check valve to stop back flow when an outlet is opened.
For what it's worth it could be on the same floor as the cylinder, and taken somewhere handy to where the bathroom in question is, say 2.5m in the room below for example.
The pump is fed from the secondary circuit.
Simple and safe.
bronze would be in the return part of the hot pipe don't think actual position should matter so long as it is in the return as all that pipe would be below header level as therefore should self prime. only thing i'm now thinking which maybe what you are thinking. is would the neg pump suck the return? if so again a single check could be put in the return
after the return tee and immediately before the bathroom taps (probably under the bath or in the bit of the loft that is unused due to pitch of roof)
I said that already Kevin, all secondary circuits return back into the cylinder about 1/3rd down and should have a check valve to avoid drawing water from the cooler return tapping.
To answer the other two questions, the pump would be as low as possible, to avoid sucking in air.
You remember I said I wouldn't guarantee it, if the booster pump was under the bath for example on the same floor as the storage tank, you would have a very low head, possibly too low, the 600mm I mentioned for the tank to be above the booster pump would be the minimum. Whereas if the booster pump was in the room below you would get a 2.5m head and no problems
I’ve been away for a few days & just catching up with the posts – feels like I’ve dropped a few wasps into a bottle & given it a good shake.
Seriously - thanks for all your posts – I’ve certainly learnt some – and most importantly, I see now that my original plan was rubbish – every time the temperature-controlled valve cooled off & opened, the pressure in the loop would drop & the booster pump would fire up again.
Some more details, arising from the posts.
(The general idea was to save water, & not have to hang around for minutes every time I want to wash my hands, & not to have a system that’s wasting electricity & heat by priming the system with hot water all day. Could use a timer, but sometimes nobody’s around & other times someone’s around all the time (teenagers)).
Tank, cylinder, twin booster pump & bathroom all in the loft. Bottom of tank is about 2 metres above the floor, cylinder on the floor under the tank. New bathroom sideways, around the corner 16 metres away.
Booster pump manufacturer says the pump MUST go next to the cylinder & ‘push’ the water, and not in the bathroom & ‘pull’ the water through long pipe lengths. I guess this puts paid to ideas of the booster being sited away in the bathroom. Recommended pump is 1.5 bar.
Norcon - I like the idea (if I’ve understood you correctly) of a timed valve (button to push as you come into the bathroom?) that gets the booster pump running for long enough to get the HW along to the bathroom, & by the time you’ve done the necessary, the HW is waiting for you at the tap.
I was just going to circulate the water back into the cylinder, but there’s a suggestion that is dangerous? I was imagining that the booster would take water from the cylinder & pump it along to the bathroom & the return brings it straight back into the same cylinder – result is circulation but no pressure rise?
Is this what the ‘throttling’ is about?
“You must maintain the pressure as it is a negative head system.”
Just to clarify - are you saying that the negative head pump needs some back pressure when it’s pumping to work properly? Or is the need to maintain the pressure when the booster has switched itself off, and is waiting for a pressure-drop to activate itself again.
Just to check I’ve got your design right
(I’ve got no means of drawing a diagram, so …)
At the tank …
Tank – vented
From the tank - feed to HW cylinder
From the HW cylinder – feed to booster pump (hot side)
From the booster pump (hot side) – 22mm feed to bathroom (shower, basin)
At the bathroom - just before the first hot tap …
Branch off to electrically operated valve, then non-return valve ?, then back home to the cylinder.
Do I really need restricting ‘throttlers’ (valves, microbore) for the return? I was going to use 15mm – same as the query above.
Regards BW2
Seriously - thanks for all your posts – I’ve certainly learnt some – and most importantly, I see now that my original plan was rubbish – every time the temperature-controlled valve cooled off & opened, the pressure in the loop would drop & the booster pump would fire up again.
Some more details, arising from the posts.
(The general idea was to save water, & not have to hang around for minutes every time I want to wash my hands, & not to have a system that’s wasting electricity & heat by priming the system with hot water all day. Could use a timer, but sometimes nobody’s around & other times someone’s around all the time (teenagers)).
Tank, cylinder, twin booster pump & bathroom all in the loft. Bottom of tank is about 2 metres above the floor, cylinder on the floor under the tank. New bathroom sideways, around the corner 16 metres away.
Booster pump manufacturer says the pump MUST go next to the cylinder & ‘push’ the water, and not in the bathroom & ‘pull’ the water through long pipe lengths. I guess this puts paid to ideas of the booster being sited away in the bathroom. Recommended pump is 1.5 bar.
Norcon - I like the idea (if I’ve understood you correctly) of a timed valve (button to push as you come into the bathroom?) that gets the booster pump running for long enough to get the HW along to the bathroom, & by the time you’ve done the necessary, the HW is waiting for you at the tap.
I was just going to circulate the water back into the cylinder, but there’s a suggestion that is dangerous? I was imagining that the booster would take water from the cylinder & pump it along to the bathroom & the return brings it straight back into the same cylinder – result is circulation but no pressure rise?
Is this what the ‘throttling’ is about?
“You must maintain the pressure as it is a negative head system.”
Just to clarify - are you saying that the negative head pump needs some back pressure when it’s pumping to work properly? Or is the need to maintain the pressure when the booster has switched itself off, and is waiting for a pressure-drop to activate itself again.
Just to check I’ve got your design right
(I’ve got no means of drawing a diagram, so …)
At the tank …
Tank – vented
From the tank - feed to HW cylinder
From the HW cylinder – feed to booster pump (hot side)
From the booster pump (hot side) – 22mm feed to bathroom (shower, basin)
At the bathroom - just before the first hot tap …
Branch off to electrically operated valve, then non-return valve ?, then back home to the cylinder.
Do I really need restricting ‘throttlers’ (valves, microbore) for the return? I was going to use 15mm – same as the query above.
Regards BW2
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