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expansion

Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions.Temperature is a monotonic function of the average molecular kinetic energy of a substance. When a substance is heated, molecules begin to vibrate and move more, usually creating more distance between themselves. Substances which contract with increasing temperature are unusual, and only occur within limited temperature ranges (see examples below). The relative expansion (also called strain) divided by the change in temperature is called the material's coefficient of linear thermal expansion and generally varies with temperature. As energy in particles increases, they start moving faster and faster weakening the intermolecular forces between them, therefore expanding the substance.

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  1. B

    Mini Expansion Vessel

    First post since intro! Worcester 28cdi in property when we bought. Worcester engineer when servicing says should have a mini expansion vessel in cold supply because a water meter is fitted. Boiler has worked with very few problems over the years so why is mini expansion vessel needed now...
  2. C

    IDEAL ICOS HE24 - losing pressure after heating is turned off

    Hello, I am new to the forum so hello to you all and here's hoping someone can help pin point what our issue is? I have some knowledge of our system from researching the internet. We have a three storey house. On the first floor is an Ideal Icos HE24 boiler. On the third floor is a Megaflow...
    • cullia
    • Thread
    • after boiler central heating system expansion icos ideal losing pressure turned vessel water
    • Replies: 2
    • Forum: Plumbing Jobs | The Job-board
  3. cr0ft

    Expansion Vessels

    Quick one folks. I have a spare potable water expansion vessel kicking around our unit. Rather than skip it, I was wondering if I can use it for a sealed CH circuit? I know you can't do it the other way round but my understanding is potable water expansion vessels are built to a better...
  4. O

    expansion pipe on a open vented system

    Can you please tell me the possible problems caused by the vent pipe dipping into the F&E tank below the waterline.
    • oldplumber john
    • Thread
    • cause expansion open vented pipe system vented wondering working
    • Replies: 9
    • Forum: Plumbing Jobs | The Job-board
  5. O

    expansion pipe on vented system

    Can you please tell me the possible problems caused by the vent pipe dipping into the F&E tank below the waterline.
  6. N

    Seeking advice on my expansion vessel

    I have a Vitodens 100-W WB1B 26 kw system boiler. Which I believe needs a new expansion vessel, due to when I tried checking the pressure in this vessel, I had water spray out from the valve ..... Am I right that a split may have occurred ? If so, is it a simple job to exchange new for old...
  7. S

    Sometimes water dripping from expansion overflow and sometimes sudden water discharge

    Hi, I have: - - an open vented central heating system with F&E tank in the loft. - Sealed cylinder hot water (megaflow). Guess it won't matter with the issue explained below - Boiler is flexicom hx30 heat only. Most often (but not absolutely everytime), water drips from the expansion tank...
  8. A

    Gunk escaping from cyclinder expansion vessel joint

    I have just moved into a new flat which has an unvented hot water cylinder. There is some very disgusting gunky looking stuff around what appears to be a leaking joint/valve going into the expansion vessel. At first I thought it was from a botched repair attempt using some kind of foam sealant...
    • asdf0987
    • Thread
    • attach expansion expansion vessel joint plumber though vessel water
    • Replies: 1
    • Forum: Plumbing Jobs | The Job-board
  9. S

    No filling loop and red expansion vessel installed. How to represurrize heating?

    Hi, I need bit of an advice about finding the filling loop in my heating system. Apologies for long description but thought to cover as much so relevant solutions can be suggested. I have spent endless hours searching internet including this forum and everywhere it is mentioned there must be...
    • samsg30
    • Thread
    • expansion expansion vessel filling filling loop heating installed vessel
    • Replies: 28
    • Forum: Plumbing Jobs | The Job-board
  10. S

    Expansion tank overflowing

    My expansion tank keeps overflowing and my overflow pipe is blocked ,so water keeps coming through the ceiling. Had plumbers in twice and had tank emptied and new ballcocks fitted to cold water tank and expansion tank. They are unable to access overflow as it is in a very tight space they say...
  11. I

    Expansion Vessel Thread!!?

    Hi, does anyone happen to know what the thread size is on a Baxi 105 HE exp vessel. Its certainly not 1/4 o 3/8, really struggling as I need to site the vessel away from the boiler and unable to send back.
  12. A

    Leaking Zilmet 11A solarplus expansion vessel

    Hi all, Got a customer with a leaking expansion vessel on the solar thermal side of the system that is installed. The solar thermal system is a Kingspan solarplus with a flat roof collector and the expansion vessel has started to leak on the weld area. There is an indirect solar tank by...
  13. T

    Pressure relief valve leak

    Hi people I have a Saunier Duval Themaclassic F30E which has been releasing water from the PRV. It was initially letting out a bit when the pressure got close to 2 bar but seemed to be ok all winter, after I removed and refitted it and also flushed out the whole system and refilled. The...
    • tucker1
    • Thread
    • dripping expansion however leak pressure pressure relief valve registered relief valve
    • Replies: 3
    • Forum: Plumbing Jobs | The Job-board
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