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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. D

    Cordless expansion vessel pump

    Hi, I've been looking at cordless inflator for recharging ex. vessels. Does anyone use one and can recommend or advise to stay away from any particular ones? I'm keen to get something better than the foot pump I use at the min, but don't wanna chuck £100 at something that's useless. Thanks
  2. JLS

    Expansion vessel sizing question (because it's driving me mad)

    Hi all, I wonder if someone can explain something to me when it comes to expansion vessel sizing. On the basis of about 4% expansion at 100degrees one would think that for a 200l closed system an 8l expansion vessel would be sufficient, with a bit of a safety factor say 10l. Worcester...
  3. T

    Do I need an additional expansion vessel

    Before I call a plumber ......... My boiler (Gloworm 18sxi) slowly loses pressure and I'm having to regularly top it up. There are no obvious leaks anywhere and no discharge from the PRV as far as I can tell. Just reading through the manual for the boiler, it says that it has an internal 8...
  4. P

    Unvented expansion vessel pressure

    Plumbed the property back in 2004 and was back again to move both vessels to make space for a coat rack. No issues in 14 years apart from the big frost in 09/10 splitting a copper run to the ensuite shower and nearly flooding the property. Does anyone know the pressure...
  5. MrYates

    Glow worm Ultracom 30sxi expansion vessel replacement.

    After reading about problems and relating them to my situation it seemed that the expansion vessel could be faulty. I depressed the schrader valve inner. After a brief and insignificant exhalation, I gave it a pump. There was a gurgling bubbling noise from the EV. On re-testing for pressure...
  6. S

    Told boiler needs a new expansion vessel along with pressure relief valve - how much should this be?

    Hi We have a vaillant turbo max 824e rs combi boiler that has been serviced and we've been told that the boiler is found to be gas safe but is in need of a new expansion vessel along with a pressure relief valve. How much should be expected to pay for this (Coventry)? I have only one quote...
  7. Bogart

    Gunge in expansion tank.

    Had a quick loook in the CH feed and expansion tank as have been meaning to flush out the sysytem and refresh the inhibitor. Put in fair bit of Fernox F3 few weeks ago and due to one thing or another it is still in there.Anyway on looking into the tank saw a sort of clear coloured gunge sitting...
  8. F

    Megaflo Air Bubble not taking expansion

    I noticed today that the pressure gauge on my incoming water supply was showing over 5 bar and creeping up fairly rapidly until it went past 6 (that's the max it goes to) and continued. The Megaflo pressure reducing valve should be 3 bar, and this is normally what the gauge shows. The only thing...
  9. P

    Hot water pouring into the central heating expansion cistern

    Homeowner here trying to solve central heating problems. Just realized hot water pouring into the central heating expansion cistern from CH supply pipe vent, am I right in thinking that essentially the boiler is producing more hot water than it knows what do with and this is causing some to go...
  10. M

    Replacing expansion vessel on...

    A vailliant turbomax plus. This one has the flue that exits the back of the boiler. Is it easy to take this off the wall and put back together? Cheers
  11. M

    Dripping valve on domestic expansion vessel 4 year old system

    I'm hoping someone can please help as I'm struggling to find a solution I've a 4 year old house and the system was fitted as new. It has a large water tank and an expansion vessel however every morning I'm woken up to the sound of water dripping through this fitting as shown below. This value...
  12. M

    Expansion tank boiling - PLEASE HELP!

    I moved into a 1980's house a few weeks ago. The house has a Ideal Heat 30 boiler in kitchen with cylinder in airing cupboard and tanks in loft. Under boiler there are 3 motorized valves, 2 for heating and 1 for HW. The 2 heating valves are wired together into stat (as there arent seperate zones...
  13. K

    Fill and expansion wrong way around causing air ingress?

    I am receiving conflicting advice on whether the fill and expansion pipes on our new system are the wrong way around and the cause of air noise at the pump weeks after installation as well as the magnaclean keep gaining air. We frequently get air bubbling noise in the pump even after repeated...
  14. B

    Expansion tank - charging and system pressure

    Hi all. This is my first post, and I'm a homeowner and not a heating engineer or plumber, so apologies if my knowledge is a bit off. To give a bit of history we had a problem with water hammer in our pipes so had a pressure reducing valve fitted under the kitchen sink. The local water company...
  15. T

    Expansion Vessel for a Boiler

    Hi Guys, My expansion vessel has burst.. What is an average size I should be looking for in an expansion vessel for my heat only boiler, and are there any good brands I should go for? Thanks!
  16. J

    COMBI 2 ZONE + UF + EXPANSION VESSEL ADVICE

    Hello i'm new to the forum, I've done a little searching on here and still have questions. Some history... I had 11 double rads in my house then i extended the house and added underfloor heating and 4 more double rads, the extension was all plumbed in and has been running for a year now. My...
    • Just a geez
    • Thread
    • advice combi expansion expansion vessel forum plumbing vessel zone
    • Replies: 10
    • Forum: Plumbing Zone
  17. Bogart

    Vent pipe on expansion tank.

    Have inherited a half cocked system which am now trying to sort. Attached is a photo of the setup. well part of it. Am just being certain what the 2 pipes on the top of the air seperator are.Think I am correct in saying the 22mm pipe is the vent and the 15mm pipe is the feed/expansion one. Is it...
  18. V

    Has hot water from expansion pipe damaged cold water storage tank?

    Hi, Trying to get my head around what may have caused our, admittedly very old, plastic cold water storage tank to split and leak through the bathroom ceiling. We have what I believe is referred to as an open vented system - conventional boiler, cold water storage tank and small header tank in...
    • Venger
    • Thread
    • cold cold water cold water storage damaged expansion hot hot water pipe storage tank water water storage tank
    • Replies: 10
    • Forum: Plumbing Jobs | The Job-board
  19. Bogart

    Expansion tank is it big enough.

    Doing a bit of a revamp of heating system some rads out new ones in . Took old galvanised expansion tank out of loft. Now I reckon this thing had a capacity of a good 100 litres. Looking at replacements they seem to be 18 litre and that is it. Now I have some 22 rads and what with a run to and...
  20. J

    Expansion Relief Valve

    Hi, I am relatively new to installing and repairing unvented cylinders, having worked largely on vented systems up until now. Today I have come across a megaflow that has a TPRV but no Expansion Relief valve on the inlet. Is there ever a situation where the ERV isn't required or does not have...
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