temprature sensor

[jerickos]

hallo i want to make the boiler starts at 30c and stops at 70c and starts again when the temprature falls to 30c again.
how can i make it any ideas please?


jerickos
greece

 

[DP]

To modify an appliance will effect your house insurance.

If the boiler temperature was to drop from 70 to 30 before it fired again, you would find that the house would not heat up.. This is exactly what was happening on one boiler only the temperature was dropping to around 45 and the house never heated up.

Temperature rise in a low water contant boiler is rapid so 70 is reached in no time at all. Takes a long time for the temperature to reach 30, so no heat coming out of the boiler other than residual heat

 

[jerickos]

dear dp

i dont want to heat up the house,im talking about the water boiler for the suppliment of the house with hot water.this is not have to do with the heating
system. Any ideas how can i do it?

friendly,
jerickos
greece

 

[Agile]

You have not described what type of boiler you have.

If its a modern type then you could build a Smidt trigger circuit with a wide hysterisis. If not then modifying a mechnical thermostat could ne used.

Can you explain why you want to have this unusual operation?

Tony

 

[DP]

It involves using a relay.

Click on my profile and sent me an email. Will email a drawing.

 

[Moss5]

This method uses two thermostats and one relay.
http://cpc.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=HG00007&N=411
http://cpc.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=HG00084&N=411
http://cpc.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=MC00227&N=411
A wiring diagram here: -
http://rapidshare.de/files/15645488/2_thermostats_1_relay.jpg.html
(Scroll down the page and click on the 'Free' download box).