Relay switches

[yebaws]

I wonder if an RF tank sensor would not be better than the pipe sensor as that seems to be the major problem?

What do you mean by an RF tank sensor please?

 

[EFLImpudence]

Radio Frequency - wireless.

 

[yebaws]

Radio Frequency - wireless.

Thanks. I'm not sure how this would help though? Which tank would it be on?

 

[EFLImpudence]

I don't know.

I am quite often unsure of what Eric has in mind.




I am also unsure how your system is different than a conventional set-up and why it requires any relays

 

[yebaws]

I don't know.

I am quite often unsure of what Eric has in mind.




I am also unsure how your system is different than a conventional set-up and why it requires any relays

I am unsure of everything now.

I think I could solve the pipe stat problem with another (non-latching) relay, so that instead of the charge pump powering the ZV and EP and being wired in parallel to them, it would switch a relay that would allow power through from the programmer to the ZV and EP. The Charge pump would be powered from an independent permanent source that would have to be switched by another (oh no) relay from the programmer and this power would go through the pipe stat before reaching the charge pump.

But presumably it is possible to have a switching relay that can output two independent supplies?

 

[EFLImpudence]

I think I could solve the pipe stat problem with another (non-latching) relay, so that instead of the charge pump powering the ZV and EP and being wired in parallel to them, it would switch a relay that would allow power through from the programmer to the ZV and EP. The Charge pump would be powered from an independent permanent source that would have to be switched by another (oh no) relay from the programmer and this power would go through the pipe stat before reaching the charge pump.

But presumably it is possible to have a switching relay that can output two independent supplies?

Is this where you are going wrong?
The (charge) pump should not power anything; it should be powered by what ever device is calling for heat in the situation.

I am confused by your original post.
Please answer me this; what happens and comes into operation when the programmer is calling for Hot Water?

 

[yebaws]

Is this where you are going wrong?
The (charge) pump should not power anything; it should be powered by what ever device is calling for heat in the situation.

I am confused by your original post.
Please answer me this; what happens and comes into operation when the programmer is calling for Hot Water?

Well, the buffer tank is calling for heat when the charge pump comes on, and the power to the pump does come through the cylinder stats if you could call that the thing calling for heat powering the pump. Programmer calling for hot water will start the CH / HW circulating pumps. If there is a charge in the buffer tank they will then extract this water, if there is no charge the ZV and EP will power up and hot water will be imported from the boilerhouse.

Untitled

• yebaws
• 21 May 2015
• 1

Untitled

• yebaws
• 21 May 2015
• 1

 

[ericmark]

I could easy write a PLC program but find PIC's harder with a Arduino between the two with price and ease to write program.

I have tried to understand the system. From what I can understand when the tank in the house is cold you want it to exchange the water with the tank outside which has hot water from a solid fuel heater?

Where I see a problem is for the system to know if the water outside is hot or cold?

Although a sensor on the pipe can sense when the hot water has run out it can't detect if there is hot water there before it starts pumping.

The only way is to have a timer which tries every so often or some manual switch.

Before working out a circuit try doing a logic map.
Calling the thermostats T for top B for bottom and P for pipe.

T + B + P pump run.
B + P pump continues to run.

The problem P will not be active until pump runs a simple push button by-passing P could start it and the system only auto stops.

 

[yebaws]

Where I see a problem is for the system to know if the water outside is hot or cold?

Although a sensor on the pipe can sense when the hot water has run out it can't detect if there is hot water there before it starts pumping.

When the programmer initially calls for heat after being off, unless the buffer tank has a full charge (bottom stat is hot), the zone valve will open and the export pump, which brings hot water from the boilerhouse into the house will fire up. This hot water will then circulate around the CH and HW circuits. The pipe stat is on the incoming pipe from the boilerhouse. So the water will circulate past the pipe stat without the charge pump being on. When the charge pump comes on it will draw of water from a T downstream of the pipe stat.