Im an apprentice looking for some information on central heating systems

[JamesE]

Hello, Im an apprentice and I've been set the task of doing a bit of research on central heating systems. I think I have a fairly basic knowledge of how they work and how to wire one up. However, I was hoping to gain a bit of an understanding about how some of the individual components work electrically. ie. cyclinder stat, room thermostat, boiler, pump, mid position valve, programmer. What I want, and am having trouble sourcing, is a gut level understanding of these components. I am aware of what they do, but not how they do it. I might be barking up the wrong tree? Any ideas where I might be able to do some reading on these items, or maybe a better place to ask these questions?

Cheers, JamesE.

 

[ron55]

Very basic:-

The cylinder and room thermostats are more than likely bi-metalic strips. A bi-metallic strip made by laminating two differen metasl together. They expand and contract when they are heated or cooled and make or break the switch that controls the power to the element.

The pump is an electric motor with an impeller on it that drives the water around the system.

The mid position valve is a mechanical valve that has a motor fitted to it. The motor moves the valve to divert the water flow to various water circuits.

The programmer is an electronic control system that tells the motors, valves, pumps etc when to turn on and when to turn off.

As I said, very basic.

Cheers, Ron

 

[Blueflash]

Ask a specific question about each component one by one. Giving any questions as answers come back. A heating circuit is just "making" or "breaking" contact to switch on or turn off due to demand. Nothing that complicated about a conventional heating system.

 

[m4fiaafg]

see if u can get hold of a books its called plumbing level 3 it has a jtl mark on it i think this will be very helpful

 

[ajelec10]

I have a book called Central heating fault finding and repair by john reginald, read and understand this and you'll be better than a plumber.
Regards
AJ

 

[andyb]

I have a book called Central heating fault finding and repair by john reginald, read and understand this and you'll be better than a plumber.
Regards
AJ

I think we're all better than plumbers ajelec10

 

[ajelec10]

Well you know what they say an electrician is a plumber with brains

 

[JamesE]

Good advice. I asked for a specific answer to a vague question. Maybe not a good start Ok, so a specific question. I found a spec sheet on honeywell's website for room thermostats. They seemed to do both a digital one, and a mechanical one with bellows to make a switch. These I think I understand. However, I was unable to find a spec sheet on thermostats with a bimetalic strip. I think I understand how the strip makes and brakes a connection. However, the bellows reacts to the ambient temperture of the room, (I think) as the temperture changes the pressure of the liquified gas inside, makes or brakes a connection. The digital thermostat has an internal sensor for the same purpose. How does the bimetalic strip sense the temperture of the room? Or is it an older model designed to be controlled by the programmer only, and to be set by the client?

My boss, I think wants me to understand how these things work so I can trouble shoot them. Plus i find it interesting Cheers guys.

Next question.

What do we do to a boiler when we stick our wires into it. Haha. Spark for ignition definantly. Some kind of control from the valve. Kind of like a hob? Nothing like a hob? Cheers.

 

[fog]

i think the bimetal strip senses the room tempreture by the size of the piece of metal its been designed that way when you reach tempreture the metal strip moves and makes a contact/breaks contact the manual setting of say room stat actually moves the two pieces of metal further or closer together and as tempreture rise to the required level the metal makes/breaks the contact signalling to turn boiler off or on depending what is required reading back doesnt sound correct but you might get the jist of it, i to have found honeywell info very useful another site to browse is diy doctor loads of useful stuff

 

[JamesE]

So the bimetalic strip also reacts with the ambient temperture of the room dependant on how close or far the strips are from one another? This works in the same respect that when current is flowing through the strip and a connection is made, when the desired temperture is met the strip brakes the connection? The connection braking though, is that down to the room meeting the correct temperture, or the strip getting hot because of the circuit being made through the strip?

 

[Spudnik]

Bimetal strips are one strip made of 2 different metals that react differently to temperatures.

I believe the strip bends or shrinks and makes or brakes contact therefore completing or breaking the circuit.

 

[andyb]

The bi metal strip has two different metals with different characteristics. When they heat up, they will expand at different rates so that they bend. This makes or breaks the contact.

Sorry Jason I've just read your post.