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Heating, ventilation and air conditioning (HVAC) is the technology of indoor and vehicular environmental comfort. Its goal is to provide thermal comfort and acceptable indoor air quality. HVAC system design is a subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer. Refrigeration is sometimes added to the field's abbreviation as HVAC&R or HVACR, or ventilating is dropped as in HACR (such as the designation of HACR-rated circuit breakers).
HVAC is an important part of residential structures such as single family homes, apartment buildings, hotels and senior living facilities, medium to large industrial and office buildings such as skyscrapers and hospitals, onboard vessels, and in marine environments, where safe and healthy building conditions are regulated with respect to temperature and humidity, using fresh air from outdoors.
Ventilating or ventilation (the V in HVAC) is the process of exchanging or replacing air in any space to provide high indoor air quality which involves temperature control, oxygen replenishment, and removal of moisture, odors, smoke, heat, dust, airborne bacteria, carbon dioxide, and other gases. Ventilation removes unpleasant smells and excessive moisture, introduces outside air, keeps interior building air circulating, and prevents stagnation of the interior air.
Ventilation includes both the exchange of air to the outside as well as circulation of air within the building. It is one of the most important factors for maintaining acceptable indoor air quality in buildings. Methods for ventilating a building may be divided into mechanical/forced and natural types.

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  1. R

    power tools needed to install central heating

    what power tools are needed to install a central heating system?
  2. milleniumaire

    URGENT F.20 after refilling central heating system

    Today I partially emptied the central heating system (1st floor and loft) so that I could disconnect an old towel rail and install the pipe work ready for the new towel rail. All went well and I have two capped pipes sticking out of the wall where the new towel rail will be fitted. Having...
  3. KarlAtkins

    What could be stopping heating working

    So I drained my Central heating system today just to remove 1 radiator in a room I'm decorating. When I refilled the system the central heating nor the hot water will work. I thought it was the motorised valve so I replaced that but to no avail, so the valve came with a new 3 way port so I...
  4. R

    Oil Fired Central Heating Tank Question

    This is what it looks like. It has been inspected and it is still servicable just needs cleaning up and painting. Yes, I know it's ancient and could do with replacing but so is the owner and funds are limited. Has anyone in PF land got any idea of how the gauge works? Is it a float mechanism...
  5. A

    Central Heating Drain Down

    Needing to change a radiator in bathroom and will need to change out trv and lock shield. On the bottom radiator I have this valve but no drain off attachment. What can I add to this to attach a pipe to drain off.
  6. N

    Central heating pump and boiler

    The house has a gravity heating system. I replaced an old failing pump Grundfos UPS 15-50 (130) with Grundfos UPS3 15-50/65 130 I have drained the system and bleed the radiators for air. The problem is that since replacement of pump boiler Glow warm (about 15 years old) comes on for about 5...
  7. K

    Central heating not working 3 port valve?

    Hi all, Not posted for some time but come up against a small problem. Been off the tools for many years now but I think I know the issue but looking for some reassurance Boiler isn't firing when programmer and room stat is calling for heating, but does for HW. It's a Y plan system, new house...
  8. milleniumaire

    Central Heating System Design

    I'm looking to expand my central heating system by adding a new bathroom UFH zone. I'm also changing the pipes feeding the loft radiators to 22mm, instead of 15mm. Early discussions with my heating engineer talked about introducing a Low Loss Header and one or more additional pumps. The...
  9. CorgiDirect

    Have you seen this excellent price on the Fernox F1 Central Heating Protect 500ml ?

    Have you seen this excellent price on the Fernox F1 Central Heating Protect 500ml ? Only £13.17 ex vat. Check out the full range of Fernox product here -
  10. L

    No hot water and heating comes on! Changed 3 port valve.

    I wonder if anyone could help. Problem: We have no hot water and the heating comes on when we switch the hot water on from the boiler programmer to heat the hot water up. Our boiler is a Potterton Suprima or (Supr1ma). What we’ve done so far: My neighbour switched the three port valve so...
  11. N

    Heating / hotwater appliance advice please.

    My daughter lives in a smallish 2/3 bed semi that was built in 2003. The house has one bathroom and an en-suite shower. It has mains gas central heating and hot water supplied from a wall mounted heat only boiler and a Boilermate 2000 thermal store which were installed when the property was...
  12. J

    Should I replace central heating pipework.

    Hi This is my second question and follows on from discoveries made while investigating dropping flow rates where you guys contributed a lot. I have made an access point to the crawl space and had a look around. Let me say at this time we are a living in a cottage so all is on one level. A...
  13. Stants

    Trouble draining Heating system

    Hi all I have an old Vented system header tank etc.... ( im very soon replacing the whole lot ) I need to move the header tank so tried to drain down the system and the Tanks not emptying put hose on downstairs Rad to drain, and water came out but I'm pretty sure all I've done is empty...
  14. CorgiDirect

    Learn how to install modern, efficient wood-fired heating systems

    CORGIdirect Biomass Manual - Domestic - EEM3. This manual is for operatives who are trained in designing and installing domestic heating systems and who wish to learn how to install modern, efficient wood-fired heating systems -
  15. Jock Spanners

    To seal a central heating system or not?

    Good morning everyone, I have a big old vicarage which needs a new regular boiler. They also want fancy mixer taps in the kitchen . They have two hot water cylinders linked together, a shower pump and curved old radiators in the bay windows. I'm agonizing over what to do. The easiest option is...
  16. CorgiDirect

    Best Prices on top, Ideal, Vaillant, Glow Worm, Heating Spares

    We have introduced a range of top heating spares from select manufacturers , Take a look here Heating Spares - CorgiDirect -
  17. S

    Underfloor heating worries

    Hi guys, I'm having some trouble with my builder and the plumber who fitted my underfloor heating. In a nutshell, the plumber has laid Hetta aluminium pipes over c. 40 square metres comprising of two zones. The builder has then laid around 6cm of semi dry aggregate-based fibre screed. He's then...
  18. J

    Central heating in a garden outhouse...

    Hi there, I am building a single storey outhouse at the bottom of my garden and I want to install two radiators in there. I’m just trying to ascertain whether it will be feasible to just connect them to my existing central heating circuit in the main house? My current boiler is a Vaillant...
  19. B

    Hot water only when heating radiators.

    Hello. I have a Worcester Greenstar 24 Ri boiler linked to a Megaflo cylinder. The boiler heats water for central heating but when I want hot water only the boiler does not fire up. I can get hot water when the central heating is on, but not ideal in the summer. The boiler is only 18 months old...
  20. D

    Heating water has started heating the radiators as well!

    Hi, Up until a few weeks ago heating the water (we have a water tank) used to heat the radiators in the bathroom and the en suite. For some reason our water heater has started heating all the radiators in the upstairs of the house apart from the bathroom, en suite still heats up though! Any...

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