http://www.diynot.com/wiki/ 2009-11-19T21:52:30+00:00 http://www.diynot.com/wiki/ http://www.diynot.com/wiki/lib/images/favicon.ico text/html 2008-03-28T20:43:28+00:00 http://www.diynot.com/wiki/plumbing:air_admittance_valve?rev=1206737008 These are NOT normally referred to as AAV's Big ones (which fit 100mm diameter pipe or above) are often known by the trade-name Durgo. They are designed to let air IN to waste or drain system, so that siphoning does not occur. Such siphoning can “pull” the water out of a trap so smelly air passes upwards. They do NOT let air out. Individual fittings are available from 32mm diameter up, or they can be built in to a trap, such as this one - the little part which looks tacked on the top is the… text/html 2008-03-28T20:41:49+00:00 http://www.diynot.com/wiki/plumbing:automatic_air_vent?rev=1206736909 Automatically vents air from system whilst filling. AAV's have to have their caps left unscrewed for them to be able to let air out. They are used at high points in pipework where air could collect. Sometimes, for example in or near boilers, they MUST be left permanently open. When they get old they are inclined to scale up and leak water out, in which case they should be replaced. Note that when the cap is left undone they will let air in if the water is drained from the connected pipe, whic… text/html 2008-03-24T20:45:56+00:00 http://www.diynot.com/wiki/plumbing:boilers?rev=1206391556 * gas_boilers * flues text/html 2008-04-07T09:25:02+00:00 http://www.diynot.com/wiki/plumbing:definitions?rev=1207556702 Please note these are not definitive definitions they are meant to give some guidance. AUTOMATIC AIR VENT (AAV) automatically vents air from system whilst filling urlAIR ADMITTANCE VALVE (AAV) allows air to pass in only one direction - into the soil and drainage system AIR SEPARATOR connects beetween the flow and vent on open system to assist in air removal picAIR VENT lets air into a room or compartment for combustion or cooling AUTO BY PASS valve which opens the bypass automatically to … text/html 2008-03-25T16:33:53+00:00 http://www.diynot.com/wiki/plumbing:faq?rev=1206462833 Frequently Asked Questions 1) Thermostatic Radiator Valves sticking shut. 2) How to balance a CH system 3) Motorised Valve Failure 4) Central Heating Guide. 5) How to flush a heating system with mains water. 6) Refilling a sealed system 7) Repressurising the Pressure Vessel 8) Radiator Problems. 9) Bleeding a ch pump 10) Water is coming out of boiler's "pipe" 11) Boiler kettling 12) Temporarily removing a radiator 13) Can I get a CORGI engineer to "sign off" an installa… text/html 2007-09-13T09:09:57+00:00 http://www.diynot.com/wiki/plumbing:filling_loop?rev=1189670997 How to restore the pressure in a sealed heating systems Sealed heating systems, as are almost always found with combi boilers, need to have their pressure checked and topped up from time to time. In most cases the pressure gauge will be on the front of the boiler and should register 1.0 to 1.5 Bar. text/html 2007-09-12T09:18:07+00:00 http://www.diynot.com/wiki/plumbing:flues?rev=1189585087 Description of open, balanced and fanned flues. Flues can first be divided into open flues and closed flues. Open flues are also known as Conventional Flues (CF). Closed flues are better known as Balanced Flues (BF) or Fanned Flues (FF), and are used with Room Sealed (RS) appliances. text/html 2008-01-09T12:12:21+00:00 http://www.diynot.com/wiki/plumbing:flushing_heating_systems?rev=1199880741 How to flush a heating system with mains water. Background. The steel elements (radiators) in heating systems tend to corrode over time, the speed of this depending on how much oxygen (air) is available and whether a chemical inhibitor has been added. text/html 2007-09-12T09:18:07+00:00 http://www.diynot.com/wiki/plumbing:gas_boilers?rev=1189585087 The boiler is the device where fuel (gas, oil, etc.) is burnt and the heat transferred via a heat exchanger to water which then circulates around the heating system. The key control on any gas boiler is the boiler thermostat which operates the gas valve. Modern boilers are much more sophisticated and include a wider range of controls. text/html 2007-09-12T09:18:07+00:00 http://www.diynot.com/wiki/plumbing:heating_controls?rev=1189585087 Heating systems require a range of controls to ensure that they operate safely, efficiently and according to consumer demand. The controls usually comprise the timer or programmer, the cylinder stat, the room stat, one or more motorised valves and the wiring to link these together. Often there will be a junction box where the wiring connects. text/html 2007-09-12T09:18:07+00:00 http://www.diynot.com/wiki/plumbing:heating_systems?rev=1189585087 Open Vented Systems Traditionally all heating systems were Open Vented, meaning the water was fed from a feed and expansion tank and the boiler was vented via the flow pipe and vent pipe. Pressures in such systems are typically low. Today sealed systems are becoming more common. text/html 2008-03-24T20:47:45+00:00 http://www.diynot.com/wiki/plumbing:installation_techniques?rev=1206391665 PTFE Tape/ Sealing Joints Pushfit connectors Soldered Connectors Compression Joints Removing Olives Pipes and joists text/html 2007-09-12T09:18:07+00:00 http://www.diynot.com/wiki/plumbing:interlock?rev=1189585087 A DESIGN PRINCIPLE required by Building Regulations, which prevents a boiler from firing when there is no call for heat. For more explanation, see main Wiki entry. text/html 2009-03-23T19:26:04+00:00 http://www.diynot.com/wiki/plumbing:motorised_valves?rev=1237836364 Motorised valves (MV) or Zone Valves are used to divert the flow from the boiler to either the DHW cylinder, the CH radiator circuits or both. In some cases the CH circuit may be divided into 2 or more zones, each requiring an MV. Two Port motorised Valves Two port MVs are either open or shut. I most cases they open when powered up and close automatically when power is cut off. When open they operate a micro switch which will in turn operate the boiler and pump. text/html 2008-03-24T20:46:49+00:00 http://www.diynot.com/wiki/plumbing:radiators_menu?rev=1206391609 * Filling loop * Flushing heating systems * Heating Controls * Motorised Valves * Thermostatic Radiator Valves - TRVs text/html 2007-09-12T09:18:07+00:00 http://www.diynot.com/wiki/plumbing:thermostatic_radiator_valves_-_trvs?rev=1189585087 Thermostatic Radiator Valves (TRVs) are often fitted to radiators to give a more responsive control of the radiator heat output according to the air temperature in the room. The head of the TRV has a sensor which responds to the air temperature around it. When the sensor expands on warming it pushes against a pin which closes the valve. text/html 2007-09-12T09:18:07+00:00 http://www.diynot.com/wiki/plumbing:worcester_240_air_pressure_switch?rev=1189585087 The Worcester 240 boiler is fitted with an air pressure switch, which enables the boiler to activate. The air pressure switch is located in the bottom section of the boiler, behind the grey panel, to the left of the two circuit boards. The air pressure switch is connected by three wires, and has two nozzles (P1 and P2) coming out towards the back of the boiler. Air pipes are connected to the two nozzles. text/html 2007-09-12T09:18:07+00:00 http://www.diynot.com/wiki/plumbing:worcester_240_combination_boiler?rev=1189585087 Fault Finding Worcester 240 Air Pressure Switch text/html 2007-09-12T09:18:07+00:00 http://www.diynot.com/wiki/plumbing:worcester_bosch_boilers?rev=1189585087 Worcester Bosch Boilers Worcester 240 Combination Boiler