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A gas heater is a space heater used to heat a room or outdoor area by burning natural gas, liquefied petroleum gas, propane or butane.
Indoor household gas heaters can be broadly categorized in one of two ways: flued or non-flued, or vented and unvented.

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  1. D

    Efficient way to heat radiators and unvented cylinder

    I have a gas boiler heating radiators and also heating an unvented cylinder. I have a Honeywell programmer which has the water heating up 1.5 hours early morning 30 mins midday and 2 hours evening The heating is on a couple of times a day. With the energy prices I am wanted to ask if hearing...
  2. A

    Plumber Qualifications Query

    Hi. I have an elderly neighbour getting quotes who has asked for my help and opinion, I don't really have a good one as it is not my area of expertise but I am trying to help. The quotes are all similar prices but She seemed to like one person and quote more than the others and I noticed that...
  3. J

    Unvented cylinder recommendations?

    Hi all, I'm due to install my first unvented cylinder. (I've had my unvented ticket for several years, but not actually done a brand new unvented install yet). It's a house renovation, with a new hw and heating system. The house currently has an old gravity floor boiler, that will be coming...
  4. D

    Unvented water heater advise

    Been to a site today and every sink has a 15l water heater underneath on each of the prv's discharge after the tundish their is only about 200mm of 22mm copper before it enters the sink waste below each sink been like this 10+ years their is no other pipework local to each and most of the...
  5. J

    unvented cylinder v combi store

    Hi all, My customer is renovating a house. Complete renovation of the plumbing. It's a three-bed house for a young family of 3. It will have one main bathroom (bath and maybe an over-bath shower), plus two shower ensuites. I have yet to check the incoming water pressures/flow rates to the...
  6. Fogster74

    Working on heating side of system with an unvented cylinder, no G3?

    Hi all, I'm a competent DIYer with an engineering background and am active in Heritage Buildings. I never touch anything I'm not allowed to albeit I've worked on the wet side of my own heating on the central heating circuit before when I had a combi - balancing rads, add a Fernox TF1, washing...
  7. C

    Humming from unvented cylinder

    Hopefully someone can point me in the right direction. Before I start I am G3 qualified. As per usual I was asked to rectify a leak on a combination valve. I installed a like for like 3.5 bar valve, all good, however I I checked pressure in exp vessel to find no pressure at all (Never been...
  8. R

    Unvented Hot Water System

    Hi, I’ve purchased a new build property and had a few issues with the unvented hot water system. I’ve now asked the developer, builder and plumber for proof of G3 certificate of the plumbers but have been told they have no need to show me this. I’ve searched the gas safe register and it’s not...
  9. B

    Unvented cylinder won't stop heating up when CH is turned on

    I have recently moved into a house with the following heating system: Traditional boiler (Worcester Greenstar Ri 24 with only one temperature dial and no pressure gauge) Vented central heating (cold tank in loft) Unvented hot water (Excelsior cylinder with pressure gauge plus white expansion...
  10. gingalig

    Unvented and boiler heat loss calcs

    I have a house with 14kw heat loss using the whole house method, ( Navien oil system boiler ) I aimed to use heat engineer software on acceptance of the quote but have been struck down with covid, the unvented cylinder is 300ltr due too a family from Ukraine living there ( 8 people living...
  11. J


    Hi All, looking for some advice. I have ARISTON CLASSICO UNVENTED INDIRECT CYLINDER ST1 210 which has corroded at one of the main inlets and is leaking water when in operation. This unit is now obsolete and need to source a replacement. Obviously I am aware that I cannot replace the unit myself...
  12. P

    Unvented cylinder wiring

    Hello all I'm replacing 2 unvented cylinder a which are (a) end of life and (b) installed in a way which is clearly not right (no 2 port shut off valve on the heating coils just for a start, and there are other issues). The heating coils are currently controlled with 3 port valves that are...
  13. M

    Re newing G3 unvented

    Has anyone recently renewed there unvented? Is the theory a long exam?
  14. B

    installation of Boiler - Unvented tank

    As part of a rebuild (added 1st floor to bungalow and extended back) we have removed every piece of plumbing and electrics, during COVID In preparation for the complicated stuff, during the build we have ... Gledhill unvented tank (preplumbed) placed in 1st floor airing cupboard New...
  15. M

    Buffer Tank/Thermal Store addition to S Plan Plus & Unvented Cylinder?

    Hi sorry bit of an odd query here. With the increases in energy costs now and in the future we are trying to find any way to reduce our exposure (retired couple on fixed incomes). We are fortunate enough to have bought solar panels at the beginning of the year but as we head towards winter the...
  16. M

    Renewing unvented quals

    Anyone know what is involved in renewing unvented qualifications. Is it a few written questions and a practical fault finding on unvented? I got my original through my level 3.
  17. M

    Combi vs unvented???

    Hi guys. I know there’s a lot of people who are happy to just chuck in a combi on every install, whether it’s suitable or not. What I’d like to know is, in what situation do you refuse a combi? Obviously things like a 4 bathroom house might not be suitable but what about cost savings with...
  18. H

    Unvented cylinder for ASHP

    Hi all. I have an Isoflo CL170 cylinder with good few years life left in it in my system which has performed trouble-free other than the odd new immersion element. I'm getting a new ASHP fitted and the installer is recommending scrapping the Isoflo and replacing it with a Secon Trade Heatpump...
  19. B

    Boulter Camray 2 to run unvented/ pressurised

    Hello, Re-jigging a serviceable Boulter Camray 2 boiler to run presurised instead of gravity. Manual says it can but we need to fit Manual reset Limit stat and Phail tube to put into boiler for sensor -both available. (Also Expansion vessel obviously!) This seems straightfrward - any comments...
  20. R

    Unvented cylinder viability??

    I'm looking at getting an unvented cylinder fitted but want to know if it's viable before even getting a quote. My cold incoming main is only 15mm but I do get a good pressure and flow which doesn't change alot when another tap or shower is used. Would an unvented be possible?
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