Archive for October, 2008

How to Drain a Central Heating System

Tuesday, October 28th, 2008

Central Heating means heating from a central source. In Central Heating Systems water is the medium. The water gets hot so that all the areas that need it get it.

If you are planning on getting a boiler/system fitted or replaced there are certain things that you should keep in mind. One of the first things you should do is find out what type of system you already have installed to make sure you have the requirements needed for your new system. Also you should think about what you want from your central heating system, keeping in mind things such as; do you want instant or stored hot water? Different parts of your house heated independently, if so how many? And do you want your boiler hidden away?

There is no standard Central Heating System, every system is tailored to suit individual needs. Even if you only have a basic system you should still have the power to programme it correctly so that it can look after itself. You should be able to set it on a timer so that it can automatically turn itself on and off. With an advanced system you can take this one step further and have the control to set your Central Heating System so that it keeps your house at just the right temperature and gives you all the hot water that you will need. You should be able to control all of this, with your boiler burning the bare minimum amount of fuel.

Out of all the Central Heating Systems, the fully pumped systems remain the most common and popular. In a fully pumped Central Heating System the water is heated by a boiler and sent around the pipework by a pump; this water is then routed to the radiator valves circuit and to the hot water cylinder by a motorised valve. As well as this the user has a lot of control over how heat is distributed and what time and temperature it is supplied.

An important thing to be aware of with a fully pumped Central Heating System is how to drain it. Draining your system is something that you will most likely have to or want to do in the lifetime of your Central Heating System.

The main reason for most people for draining their Central Heating System is to clean the radiators. Before you do anything to the actual radiator you should turn off the boiler and any gas or electric that supplies the boiler. It is also important that you do not let any more water into the system while you drain it.

Your Central Heating tank where the water is fed into has a ball valve that is the same as the one seen in your toilet tank. This ball valve is a ball attached to an arm that, when lifted closes the valve, which means when the tank is full no more water can get in because the valve is closed. However when some water is drawn off the tank, the ball drops, the valve opens and more water gets into the tank, this is what needs to be stopped when draining your radiator. One of the best ways to stop this is by placing a piece of wood across the tank and tying the value arm to it, which will close this valve.

When all these precautions have been carried out, you should attach a hosepipe to the part of your radiator known as the outlet and run the end of the hosepipe outside. The water from your radiator will flow through the hosepipe and out of your radiator system. You must make sure before you start cleaning or replacing your radiator that all of the water has defiantly been drained out.

To make your system drain faster you should open any bleed valves on your radiators, starting with the radiators on the top floor and working your way down. When the water is drained off you are free to work on your radiator valves.catv fifters

Types of ball valve

Friday, October 24th, 2008

There are four general types of ball valves: full port, standard port, reduced port, and v port.

  • A full port ball valve has an over sized ball so that the hole in the ball is the same size as the pipeline resulting in lower friction loss. Flow is unrestricted, but the valve is larger.
  • A standard port ball valve is usually less expensive, but has a smaller ball and a correspondingly smaller port. Flow through this valve is one pipe size smaller than the valve’s pipe size resulting in slightly restricted flow.
  • In reduced port ball valves, flow through the valve is one pipe size smaller than the valve’s pipe size resulting in restricted flow.
  • A v port ball valve has either a ‘v’ shaped ball or a ‘v’ shaped seat. This allows the orifice to be opened and closed in a more controlled manner with a closer to linear flow characteristic. When the valve is in the closed position and opening is commenced the small end of the ‘v’ is opened first allowing stable flow control during this stage. This type of design requires a generally more robust construction due to higher velocities of the fluids, which would quickly damage a standard valve.
  • A teunnion ball valve has a mechanical means of anchoring the ball at the top and the bottom, this design is usually applied on larger and higher pressure valves(say 4″ and above 600 psi and above)

Manually operated ball valves can be closed quickly and thus there is a danger of water hammer. Some ball valves are equipped with an actuator that may be pneumatically or motor (electric) operated. These valves can be used either for on/off or flow control. A pneumatic flow control valve is also equipped with a positioner which transforms the control signal into actuator position and valve openin .bearing

Angle stop valve leaking

Friday, October 24th, 2008

My cold water supply line going to my faucet burst so luckily I was there before it got bad and also angle valves still works. After replacing the hose I noticed the hot water valve was corroded and was seeping water. So I thought it would be a great idea to replace all the valves and hoses in both the bathrooms. My main water shutoff at the meter does nothing but spin so I used the street one. I also shutoff the hot water heater valve and turned on all the faucets. Water still continues to run out of everything making it difficult to replace all the valves. Its not full pressure or anything but definently more than a drip. Anyways I managed to replace all 4 valves and hoses. I have no idea how to remove the compression ring on the pipe so I reused the ones on there. Problem is I now have water seeping out of all the valves! Nothing major but it shouldnt be wet at all. I tightened them pretty snug at first but still no good. So now they are on there gorilla tight but still seeping water. It is 100% coming out from the compression nut and not from anywhere else. I would have replaced the compression ring but couldnt get it off. And sweating new pipes on there is no option because the water will not stop running. Any ideas?

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Mini ball valve

Friday, October 24th, 2008

Parker Instrumentation has a new 12mm ball valve for fluid instrumentation applications which operates accurately over wide temperature range for applications including the bio-pharm and semiconductor sectors.

The valve relies on a one-piece seat/packing component which eliminates the dead space between the valve and the connections that can trap particles or allow deposits to build up. The new valve is also smaller and lighter than existing comparable valves.

Designated MB8, the 10.3mm orifice valve offers a flow coefficient of 6.42 and is rated for 2500psig/172 bar operation, It is made of stainless steel and is available in three-way, in-line and two-way configurations

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