Posted 31 October 2023

Boiler help! How much can I lower the heating and water temperatures?

4226874_1.jpg
I have a rather old boiler (Potterton Performa 30HE) and the heating and water temperature controls don't include numbers – see photo. I have read a lot about how these temperatures can be safely reduced to save money but as there aren't any numbers on the dials I have no clue how far down I can turn them! Any advice?

Currently when I turn on the heating or have a shower the boiler goes full max and hits 80 (see photo) – by turning down the temperature dials will this then only hit 70 or 60? Is either safe?

And yes, I know, a very old boiler which won't be very efficient but it is working fine and has been serviced so no plans on getting a new one!

Thanks!
Community Updates
New Comment

16 Comments

sorted by
's avatar
  1. AndyRoyd's avatar
    Lower / raise as much as necessary to provide the comfort / performance you want / prefer.

    No numbers marked as the output result is relative not absolute.
    If you must have numbers, mark your own.
    tek-monkey's avatar
    This. The boiler stats are irrelevant, what matters is the room you're heating or the tap you're using. My kitchen hot water tap is on a long pipe run from the boiler, I'm guessing that pipe takes a bit of heat out as the water never feels as warm there than in the bathroom. That said the extension was built by an imbecile so woukldn't surprise me if none of the pipes are lagged.
  2. dcb01's avatar
    Why do you keep mentioning it’s “a very old boiler”?

    No it’s not!
    It’s a high efficiency condensate boiler that your not likely to notice any major savings if you swapped for a shiny new A++++++ one.
    If it’s that “Company B…G….” telling you you need a new one, all I will say as a ex employee is the are incentivised/Forced to “Promote “
    SJM20's avatar
    Author
    I've been told that most of the parts are still easily available if something goes wrong, but some aren't – so they, BG might not be able to repair at some point in the near future.

    I signed up to them as when I moved in to my flat the overflow was pumping out loads of water due to the pressure (and had caused some serious damp because of this*) and BG had a good repair and cover offer on at the time. They easily fixed it (had the part on the van already) and I have not had any problems since. My cover is due to run out next week so going to let it run out and will then get again if/when I need to.

    I turned down the heating temperature control a fair amount and the 80 light didn't come on when I last turned the heating on (went up to 70). I will turn it down again to see if I can get it down to 60. Will then play with the hot water!

    *the previous owner took 6 months to complete the sale so this wasn't spotted when I agreed the sale, and I insisted on a boiler service as part of the agreement but they didn't submit an extra piece of paper which stated the boiler needed work.... still fuming about it.
  3. uni's avatar
    when you get your annual service, ask the engineer to balance the rads and set everything the way you want it, instead of guessing and potentially breaking your boiler by changing stuff you don't know
  4. martynhardacre's avatar
    If your water gets heated on demand then you can have it at wherever temperature you like. Think it's only an issue if it sits in a tank as there can be a chance of legionella with water standing and not being heated to a high enough temperature. Mine is at 50 degrees. On the boiler if it's your flow temperature the general advice is to set it to 60 degrees to get the best results 🏻
    Misslovely's avatar
    How often do you heat your water in tank??
    I have hot water solar panels and that warms the water up. Been hot until last week and water is like warm now.
    For showers we use electric shower
  5. TristanDeCoonha's avatar
    If it is an instant feed then you only need the water temp as high your needs. For a bath/shower (assuming tap fed) then 40 is enough.
    If using to clean grease off without chemicals, then crank it up.
    You don't need to worry about keeping it at 60 to avoid Legionnaires disease unless you are holding the water in a storage tank. The internal rank is emptied often enough to avoid that.
    Can you afford to wait a short time before you receive hot water at the tap? If so, then turn off the constant option, so you are left with on demand. This saves a bit of gas.
    How hot do you want your home? The water coming out of the boiler for the heating needs to be higher than your preferred temp so that it can lose heat into the home. That is for you to play with
    SJM20's avatar
    Author
    Any thoughts as to how I know what 40 is on the dial? Or should I just keep on reducing it a bit every day to see what temp the boiler gets up to? Having no numbers on the dial is confusing me!
  6. themachman's avatar
    Instead of trying to find the exact temperature just turn the dials to suit your needs
    I always turn the water down when I have a shower then crank it up for the dishes
    The one for radiators i have on full pelt, I know some people get the sweet spot for the condenser boiler to be more efficient, but I found the place took ages to warm up doing it that way.
's avatar