Discuss 2 way Isolator For GSHP immersion with 2 supplies and 1 load in the Electrical Tools and Products area at ElectriciansForums.net

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aydmartin

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I am going to fit a 3 phase 6kw immersion heater in a 500litre cylinder. this forms part of a 30kw GSHP system. The immersion is required as top up when the GSHP is not enough to generate enough hot water and the immersion kicks in via GSHP control to lift the temp further. It is also required as a stand alone back up system for when the GSHP is under maintanence or out of order.
I was contemplating running a supply from the C/U to the immersion and separate supply direct from the GSHP resulting in one load but 2 supplies.
Does anyone have any ideas as best way to do this. I believe there are isolators available to utilise this but i have never seen let alone used?
Or is a relay system the best way?

Any advice would be helpfu
 
L

lamb

The Dimplex heat pumps I have connected gave a low current, 230v connection for the immersion, so a contactor was always fitted.
Immersion supply went from DB, through contactor, through rotary iso and into element.
 

snowhead

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All you need is a pipe stat on the H.Pump flow, at the cylinder to control the immersion contactor.

Is the output from the H/pump over 60c?
 
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aydmartin

EF Member
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5
Location
Newport, Gwent
The heat pump sends out directly on call a 3 phase supply direct to immersion.
I also need to be able to feed the immersion direct from the DB as an emergency back up during planned maintenance and breakdown etc.
The heat pump will unlikely go beyond 60 C and the immersion will be doing the legionella protection.
I have very little experience with relays or their circuitry, I mean VERY LITTLE too.
Any assistance with how to do this will be a great help. Thanks again.


I am going to fit a 3 phase 6kw immersion heater in a 500litre cylinder. this forms part of a 30kw GSHP system. The immersion is required as top up when the GSHP is not enough to generate enough hot water and the immersion kicks in via GSHP control to lift the temp further. It is also required as a stand alone back up system for when the GSHP is under maintanence or out of order.
I was contemplating running a supply from the C/U to the immersion and separate supply direct from the GSHP resulting in one load but 2 supplies.
Does anyone have any ideas as best way to do this. I believe there are isolators available to utilise this but i have never seen let alone used?
Or is a relay system the best way?

Any advice would be helpfu
 

RogertheBodger

Electrician's Arms
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Location
Spain
Could you fit a by-pass contactor into the heat pump with a manual override switch?

Thinking some more on it, if as you say, the immersion heater is fed direct from the heat pump then there will almost certainly already be a contactor in there.

So all you would need to do is fit the manual override switch into the coil circuit of this contactor.
 
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snowhead

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The heat pump sends out directly on call a 3 phase supply direct to immersion.
I also need to be able to feed the immersion direct from the DB as an emergency back up during planned maintenance and breakdown etc.
Simplicity is the key, or K.I.S.S. if you don't mind being insulted.

You don't need 2 x 3 phase supplies from different sources, at most you only need a control signal from ASHP, which can be one of the 3 phases, to enable a 3 pole contactor for the Immersion, or have I missed something;

Does the GSHP generate 3 phase?
 
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aydmartin

EF Member
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Location
Newport, Gwent
Im all for KISS
The GSHP is 3 phase and pushes out 3 phase to the separate immersion when the heat pump is not able to cope with the demand and requires the immersion as supplementary heat
I also want to use the immersion as stand alone system for when the GSHP is isolated completely and utilise the immersion as a back up heat source during breakdown and planned maintenance etc.

As stated earlier my experience with contactors and relays is basically zero, unfortunately I need more lay terms and instruction, please advise

Simplicity is the key, or K.I.S.S. if you don't mind being insulted.

You don't need 2 x 3 phase supplies from different sources, at most you only need a control signal from ASHP, which can be one of the 3 phases, to enable a 3 pole contactor for the Immersion, or have I missed something;

Does the GSHP generate 3 phase?
 
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A

aydmartin

EF Member
Messages
5
Location
Newport, Gwent
There are certainly contactors in the GSHP yes, will need to check again when I can get to manual.
Pse advise on how I would fit the manual overide switch into the coil circuit of the contactor

Could you fit a by-pass contactor into the heat pump with a manual override switch?

Thinking some more on it, if as you say, the immersion heater is fed direct from the heat pump then there will almost certainly already be a contactor in there.

So all you would need to do is fit the manual override switch into the coil circuit of this contactor.
 

RogertheBodger

Electrician's Arms
Messages
809
Location
Spain
It wouldn't be easy describing how to fit such a switch without seeing the unit and/or circuit diagrams.

From reading your posts further it seems that you want to totally isolate the GSHP electrically, but still be able to use the immersion heater, perhaps I misread your request.

What you could use in this case is a TP&N changeover switch, This is a device connected in line with the supply to your heat pump, which when operated diverts the supply from your Heat pump to your Immersion heater, does this sound more like what you had in mind?

But if you isolate the GSHP completely will your pumps, stats etc still work?
 
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