Thermostatic Switch

[WightMan]

I am looking for a thermostatic switch that will operate on mains voltage. The switch needs to make the circuit on temperatures above about 18 deg c.
It would be better if this value was adjustable. Something like a greenhouse window switch would do well. Does anyone know where I can purchase a single item?

 

[Spark123]

What is it for?
Any good? http://www.plumbworld.co.uk/honeywell-t6360b-spdt-room-761-1361?CAWELAID=205023802

 

[dextrous]

What is it for?
Any good? http://www.plumbworld.co.uk/honeywell-t6360b-spdt-room-761-1361?CAWELAID=205023802[/QUOTE]

Wouldn't this open the circuit rather than close it at the required temerature?

 

[ericmark]

There are many different types.
Standard Thermostat has controller and sensor combined in a air sensing unit and low current.
Standard Thermostat for under floor heating has option of remote sensor and higher current.
RS Components do a 15degC And also many more the price varies from just over £2 for one shown to over a £100 for one with Capillary tube.
Also Units like shown here can use many different types of sensor again by time sensor is selected around the £100 so what do you want to do?
Click on Pictures for links

 

[ericmark]

What is it for?
Any good? http://www.plumbworld.co.uk/honeywell-t6360b-spdt-room-761-1361?CAWELAID=205023802[/QUOTE]

Wouldn't this open the circuit rather than close it at the required temerature?

Most rooms thermostats today are designed duel purpose heating and cooling and have both N/O and N/C contacts but the mechanical type often require a neutral to reduce the differential between on and off. Electronic room thermostats normally around 0.5 degs differential but mechanical types can be a couple of degrees.
This one does have N/O and N/C contacts but also includes a timer but why would anyone need to ask where to buy something so simple. Will be interesting to see reply! This one rated at 16A and has remote sensor but at £60 is bit on expensive side. It also has both N/O and N/C contacts.

 

[JohnD]

"What is it for" is the most essential question.

Central Heating room stats might be suitable but will usually only switch up to 3Amp resistive load. You can get a similar looking stat that will switch 16Amp.

It sounds like he wants to switch on a cooler or fan, but, who knows?

 

[Spark123]

What is it for?
Any good? http://www.plumbworld.co.uk/honeywell-t6360b-spdt-room-761-1361?CAWELAID=205023802[/QUOTE]

Wouldn't this open the circuit rather than close it at the required temerature?

It says SPDT which I took to mean Single Pole Double Throw i.e. change over contact when it operates.

 

[WightMan]

OK people, thanks for your comments. I will look into these. I tried to check out RS but their website is offline at the moment.
In answer to "what is it for?" I have built a solar heating system for my swimming pool. At the moment the pump only runs during the times set by the timer. I want to maximise the use of the heating system when the sun is heating the panels so I want to use a thermostatic switch to run the pump when the units reach a certain temperature. That is why the switch need to make the circuit at the specified temperature. I had assumed that central heating room stats would break the circuit at the specified temperature. Perhaps some can be wired for either as some of you point out.

By the way apologies for the incorrect posting. I was in a hurry and just cocked up!

 

[JohnD]

what pipe temp do you want the pump to start at?

Maybe a Cylinder stat would suit you better

They have a common, and a "call" (too cold) and a "Satisfied" (too hot) output, so you can use the Sat output to run your pump. From memory their temp range is something like 40C to 80C (user adjustable).
This one is 0C to 90C (user adjustable) 16A contacts. You strap it to a metal pipe or tank. This one is a good brand at a good price.
http://www.screwfix.com/prods/56303/Plumbing/Central-Heating-Controls/Horstmann-HCT2-Cylinder-Stat

http://www.screwfix.com/sfd/i/cat/pdfs/54/p4458354.pdf

Room stats are more 5C to 30C range (air temperature).


I presume your pump is 500 watt or less, mains supply, so no more than 3 amps? If it is like a Grundfoss circulator, a CH or Cyl stat will be rated at more than enough, since this is what they usually switch.

 

[ericmark]

Now we know what it is for I agree with JohnD and a cylinder stat seems good idea. Because of the way a central heating system works using Y plan most cylinder stats are change over. Only thing you need to watch for is temperature setting many will only go down to 55 deg C because that is the lowest temperature that will kill legionnaires.