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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.
Hi there,
I was wondering if anyone could advise if I should get a different plumber for a 2nd opinion.
Basically, my combi boiler is in my attic. It is overpressurised at the moment and the overflow pipe always drips.
I had a plumber round, he seemed good and honest and knew the neighbour so...
Am I correct in saying that the capacity of an expansion vessel as written on the appliance data label is the capacity of the water compartment alone and excludes the air compartment capacity?
Thanks
Hi,a customer of mine has a combi boiler and they don't have an expansion vessel for the potable hot water supply. I know there's an expansion vessel for the closed-loop central heating circuit but I doubt the combi boiler has one for the potable water. I was thinking to put one in the airing...
CLC plumbing
Thread
combi boiler
expansion
hot water
hot water supply
potable
I need a new expansion vessel, problem is I've got a optima 901 and the flue goes up about a foot and then into the back wall and the vessel is at the back, it's one of the round ones, I've got to get a engineer into do it, I'm assuming that they take the flue out and lift it from the back...
Hi,
Should an expansion vessel pressure match the pressurisation unit?
For example, if the pressurisation unit is set at 1.2 bar should the expansion vessel be set at 1.2?
Many thanks
Have an Ariston unvented hot water tank in airing cupboard with the red and white expansion vessels and a filler tap. As advised years ago on these forums when I hear that sound that the central heating water needs topping up I usually wait until cold so the gauge goes to zero and top up to 1...
KenTucky
Thread
expansionexpansion vessel
filler
no water
sound
tap
turning
vessel
water
Has anyone got a good rule of thumb for sizing an expansion vessel for a central heating system. A combi has a 8 litre vessel. And will deal with the expansion of say 8-10 rads. Could one use this as a ball park figure and multiply up from there Obviously pipe work to take in to account 22mm...
Hi, hope someone can help me with a heating pressure loss problem. My valiant boiler has been loosing pressure over the last few months, resulting in me having to top up the water every week or so. Managed to get a boiler engineer to visit who diagnosed a faulty expansion tank. (Water evident at...
Hoppers
Thread
expansion
fitting
heating
heating system
pressure
pressure loss
system
tank
Hello all, I'm currently in Ireland and in a small cottage where the plumbing system has me scratching my head a bit. When the place was done up the builders decided that the tank in the loft was no longer needed and put a tank out back in a small extension where ALL (well, except for the cold...
Mick Canavan
Thread
expansionexpansion vessel
high
pressure
system
vessel
water
Hi Guys,
Had a quick question regarding expansion vessel on a Vaillant Ecotec Plus 832. Was servicing the boiler and upon attaching hand pump to vessle after having drained the boiler, returns and flows isolated and drain off on boiler open, the vessle showed 1 bar charge.
Was wondering why...
Sandeep89
Thread
ecotec
ecotec plus
expansionexpansion vessel
plus
vaillant
vessel
I have a Maxi Pod installed and the overflow of the expansion tank keeps overflowing. i think it maybe because my expansion tank is to small. It is only a 7 gallon tank and I believe Maxi Pod recommend a 20 gallon expansion tank. Question: why do Maxi Pod recommend such a large tank?
Hi,
New to this forum and also complete novice who knows pretty much nothing about plumbing.
However I have done quite some google searching trying to find some answers.
I live in a 1st floor flat which uses an electric duel element direct unvented water heater cylinder (150 litres).
Recently I...
MrJack2021
Thread
cylinder
expansion
faulty
pressure
problems
tank
unvented
unvented cylinder
Hi
I have a leaky Gledhill expansion relief valve block a little like this one with the same spec 3bar on the black input and 4.5 bar on the red expansion relief value. It protects a 250L Gledhill unvented tank. All the input pipes have isolation valves so pretty easy to exchange components...
Hi,
Currently have a Potterton Promax Combi 28 HE A boiler and looking to replace expansion vessel due to issues with it. Looking to make sure i get the right part for it
Found this part online but it says it will Fit a Promax Combi 28 HE Plus A,Is the HE plus A and my boiler HE A the same...
CWilson
Thread
boiler
expansionexpansion vessel
order
should
vessel
Hi,
After a bit of a saga with my plumber, I need to chose boiler size as soon as possible, the plumber is not going to do any heat loss calculations or do anything to work out accurately so I am on my own. Appreciate this is not what should be doing but after some level of finger in the air...
meakinsl
Thread
boiler
expansionexpansion vessel
sizing
system
system boiler
vessel
Currently installing air to water and underfloor.theres this expansion like vessel with two 3/4 iron male threads on top and bottom of it with no bladder on between.its goes before the primary flow hits the cylinder and underfloor manifold.anyone know of its function??we don't do alot of air to...
I've recently had a prv changed by a British Gas engineer under the homecare contract that I've taken out. The valve had failed and water was pouring out from the overflow pipe.
The valve was replaced without too much issue. However, the red expansion tank above the boiler was NOT re-pressurised...
Not looking to fix this myself but could do with some insight as to what’s wrong…due to sell the house on a few weeks and not comfortable doing that without this being fixed.
CH pressure getting up to 4-5 bar and pressure relaxing through the 3 bar pressure relief valve. Connected to unvented...