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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.
According to the manufacturer's information OV PULSAcoil thermal stores are primarily designed for use with on/off peak electricity but also have two open pipe spigots (NO internal coil) for flow and return from an additional heat source e.g. a heat only boiler. The 180 store comes with a...
I hope someone might explain to me why the overflow from the expansion tank drips in the morning for about an hour after the heating fires up, it then stops and does not drip again during the day.
I have a fully pumped "Y" system as show on the accompanying drawing the dripping occurs on the...
I have just had a water meter fitted and since been told I need a small expansion vessel fitted to my domestic hot water system as the meter will have a NRV in. I have also been told no I don't as my boiler is over 10meters away from the meter and any expansion will be taken up within the...
I have Gledhill 300L unvented water cylinder storage system with Vaillant Boiler. We are using it for UFH and radiators. My plumber has fitted 2 expansion vessels
1) Zilmet - 18 Litre Red Heating Expansion Vessel & Sealed System
2) MULTIFUNCTIONAL TANKS WITH REPLACEABLE MEMBRANE
Why has he...
Do many merchants sell 1 meter long 3/4 male to 3/4 female. The 3/4 male screws in to the composite valve and the other end the expansion vessel. I presume came supplied with the composite valve. The flexi is leaking.
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...
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...
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...
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...
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...
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...
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...
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