Oil to gas combi replacement - siting and venting

Discussion in 'Plumbers' Talk' started by ColD, Jan 11, 2020.

  1. ColD

    ColD New Member

    Im having the old oil fired boiler below replaced with combi boiler this week coming.

    I'd assumed it would be something like a swap as pipework, electric and flue all right there.

    The wall pictured separates the living room from the internal garage and the chimney there has two flues, one serving the open fire, the other the oil boiler.

    One of the installers was in adding the cleaning agent pre the install and helpfully ran through a few things. One of which was they planned to mount the new boiler on the external wall of the garage. I suppose that is where the supply comes in. He seemed to be saying that the vent must be on an external wall.

    So my queries are:
    • I guess for safety it must be vented horizontally through the external wall and the existing flue cannot be used.
    • What is the best way to close the existing flue....i guess it should have some airflow and not sealed completely?
    • How will they bring the mains water, hot water pipes and electric to the new site on the wall opposite?
    Bonus question, in the second pic there is another pump looking thing....any ideas what that is? There had been a back boiler system which was sealed after a leak....to do with that?

    Any thoughts much appreciated.

    Col



    Main Boiler.jpg Main Boiler 2.jpg
     
  2. Heat

    Heat Screwfix Select

    Why are you not asking those questions of your gas installers?
    The hole left in the chimney could be fitted with a vent to allow some air circulation. The top of chimney will require a vent pot to allow air circulation but allow prevention of rain or birds entering.
    The pipes possibly can be taken at any height across the walls or ceiling.
    The mains cold and hot pipe is the problem for your installers, but probably from the nearest source - like if a kitchen is close.
    The very old blue coloured Myson circulating pump (great quality old pump) is on pipes that were a solid fuel fire probably and I notice check valves (one way valves) also near to each pump, so obviously was a dual heating oil/solid fuel system, with pumped rad circuits linked.
    The green pump at oil boiler is fairly new and you should keep it as a spare pump for a friend.
    Oil boiler is ancient - about 1985 I reckon. Warmflow haven’t made boilers with Danfoss thermostats since about that time.
    Whereabouts are you in UK?
     
  3. jonathanc

    jonathanc Guest

    As per the above post; why do you not ask the installers. Bluntly you are not clear on the works they are going to carry out. That is a recipe for disaster for you and the installer as you expect one thing, they do another and no one is happy. Confirm precisely with them before they start work, that is in everyone’s interest
     
  4. ColD

    ColD New Member

    Guys, thanks for taking the time to reply, much appreciated. I'm asking as it's the weekend, and late on Friday one of the team came over to add the cleaner to the system - I tried to get v back but missed him by about 10 mins. It was he who introduced the idea of siting the boiler on the outside wall.

    You are both spot on in what you say. I'd say like most people, I have a broad idea but its correct to say I am not clear on the venting or the details of the plumbing. When the owner was out a month or so ago, he did talk about tracking pipework from the meter over the roof of the garage but I thought boiler in same place - could be my misinterpretation. Most definitely will be around to ask these questions this week.

    I will check their ideas for the pipework, don't mind it showing in the garage, was expecting this to some degree but am not enthusiastic about anything showing in the house itself.

    Thank you so much for clarity on the old pumps...I wouldn't have been guessing, I simply had no idea. The green pump may well be new as there was work done to the system prior to us purchasing it. I will take your advice on the green pump.

    Last but not least, you are amazingly accurate on the boiler. Think the house was 1988 so your guess at the year seems spot on. Warmflow is a local producer as we live in Northern Ireland.

    Heat & JonathanC, thanks for sharing your expertise.
     
  5. Heat

    Heat Screwfix Select

    The work is very familiar to me and very common in NI as lots of dual heating systems were installed in the 80s and beyond. I am from NI.
     
    ColD likes this.
  6. ColD

    ColD New Member

    Cheers Heat. You were spot on.

    Spoke briefly to the boss and he confirmed intention to site on external wall. There's a utility adjoining the back wall of the garage and looks like there is mains water fed into there from the kitchen for a sink, washing machine and outside tap. I imagine they might going across ceiling in the garage to get the hot water pipework and consumer unit is nearby also. So hopefully it will work out okay.

    It was a dual system but before we bought the house it was briefly uninhabited and there had been both a nightmare oil leak and the back burner system had leaked also...i think might be the reason for a newer pump on the oil burner and the relatively dusty poor relative to the left.

    Anyway, will know better this week how things go! Thanks for helping me figure out what was going on.
     
    Heat likes this.

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