circulating pump - advice needed

[SteveH]

This is not a centrifugal pump, the DAB rep termed it as....an inline water circulator.

 In this case: IWC (inline water circulator) = Pump

 The Dab VA 55/130 CIRCULATOR has an impeler & the cutaway picture from the specification sheet (Click here) clearly shows it is of centrifugal design...

How does this affect the response to my previous question ?

 It doesn't... You've just been "Techno babbled" by Dab.... 

[deeside70]

steve h
thanks once again.
she sounded so convincing,when she returned to the phone after putting me on hold, while she asked a colleague.
i should have guessed.
well and truly .... techno babbled .  - nice phrase.
regards
noel

[northern installer]

being picky perhaps,but right both ways,the dab circulator is a centrifugal pump in principle,but termed a circulator as its design would not allow it to 'pick up and pump' to coin a phrase,it needs a closed circuit;anyone who has tried to use an old circulator as a pump will be aware of the somewhat disappointing results! 

[SteveH]

 Point taken NI...  I take it they have no suck ...

 Noel, you should have no concern about it acting as a generator wile water is circulating through the unpowered pump....

[northern installer]

No sucking good at all for anything other than circulating

[Alan]

Hello Noel

As per Mr Steve H post, no appreciable resistance would be added to the pump loading on top of friction losses. No electrical problems.

Regards

Alan

[deeside70]

steveH/alan
hi, thanks again for the advice.
fitted the 12 volt motor vehicle water pump in line last night and connected the PV panel to the pump using the
capacitor recommended.
got up early this morning, waiting for the sun to hit the solar and PV panels.(PV sits just above solar)
the system works really well ....so far.
i spent most of the day listening to the sound of the pump changing speed,matching the cloud cover at that time.
i had reservations about the 6 watt PV panel being too weak,but it seems fine.
only time will tell.
regards
noel

[billi]

i spent most of the day listening to the sound of the pump changing speed,matching the cloud cover at that time.

Thats like music  isnit  , what a harmony  solar electricity and solar thermal ,

billi

[deeside70]

hi all

The system worked well with the 12v motor and capacitor and PV panel up to the end of October.
Then nothing until around 20th Feb  --- gloomy short winter days. I need an alternative for next winter as this is an old stone farmhouse.
I have a wood burner without backboiler  and i intend to fit a  22mm copper tube loop inside the lower part of the 125mm stainless steel chimney, to use the heat from the top of the fire, to run a thermosiphon system which would link into my 2 tank system.
Q.   Could i safely run this circuit into the solar panel circuit near the tanks -  i have a 3 way diverter valve? This would mean using the pressure control valve and expansion vessel and 3 way valve in conjunction with solar clrcuit.
The alternative would have to be an independent circuit  with valve and vessel, 3 way diverter, control and 2 retro fit coils.   Expensive !!
Regards
Noel

[martin W]

hi Deeside....

from what I've read and been told, the general rule of thumb with a WBS heting water is there must not be any valves or anything on the WBS circuit as it is an 'uncontrolled heat source'. Basically the WBS must go directly to and from the cylinder, you are allowed put 'heat leak' rads into the circuit via injector 'T's. to dump excessive heat form the WBS once the wate ris up to temp. I'd look on the Solids part of the forum.


Just to sum this thread up, could you post what you actually bought and did to replace / supliment your 240volt navitron circulator witha 12volt lower wattage one...

cheers.

[deeside70]

hi martin/all
i sited the photovoltaic solar panel immediatly above the 20 tube panel.
the 12v electric motor/pump was placed in-line with and just after the 240v pump on the return,connected to the copper pipe with motor vehicle hose and jubilee clips.
the capacitor was placed across  the two wires from the cell, just above the motor. the system was earthed.
this system has worked well, no problems for 18 months now.

photovoltaics....Sunshine solar panel CIGS 6W - 12V £34.65 on e bay Solar panels.
motor.............Solar water pump panel.....AUDI 12v ,brush-less water pump  £55.00 ebay
capacitor.........RSH Services......£0.55   sales@rshelectronics.co.uk
rubber hose.....any motor factor......around £10.00/metre

cheers,noel

[SteveH]

 Hi Noel,

 Thanks for reporting back... I'm really pleased that your solar powered system is working well.

 Defiantly a plus point for the KISS approach... nice to know the advice was appropriate... & keep posting updates.

 Steve...

[Contadino]

This thread is interesting.

I've been running an El Cid 5 watt circulation pump from a 10 watt PV module for 4 years with no problems.  There's a diff temp controller in the mix which is self-powered from the same PV panel (i.e. the panel tops up the controller batteries each morning when the flat panel is still cold.)

You may say that my primary temperatures are lower because I'm using a FP collector, but with daytime temperatures hitting 45º in summer I doubt that argument stands up.

However, with the benefit of hindsight, I'd say that if I was opting for a tube system in the future, I'd have to think hard about whether to use a PV circulating pump.  Somehow you'd have to match the water and PV panel efficiencies - which would be beyond my abilities with tubes.  That said, I doubt I'd ever switch from FP to tubes.

[martin W]

Just had another thought on this system.. 12volt pump and 240v pump in series...

Could the 12volt pump just run due to the amount of sunlight hitting the PV panel. then if it wasnt 'man' enough to push enough water though the solar vacuum tubes the controller on the 240v pump (TDC3) would then switch the 240v pump on as well to drop the vacuum tube panel temp.

Does that make sense.

would the 12volt pump run when the vacuum panel was actually colder than the hot water cylinder? Or would this never be an issue.

[deeside70]

hi martin
morning dew on the photovoltaic panel usually prevents the two panels from kicking in simultaneously, so the 240v pump is activated until the 12v motor kicks in.

it does not matter if the panel temperature is colder than the cylinder --this is usual in the morning start-up.
the pv panel will run the 12v motor as soon as the sun hits it. hence the reason for placing the pv panel immediately above the solar panel.
the sun hits the two panels simultaneously therefore they kick in together - dew permitting.
when clouds appear, they both slow down production. sun reappears and off they both go again.
perfect.

regards
noel