Well it sounds like pump overrun, but he did say it doesn't have it, I actually asked twice. As I said the terminal is there, it's shown in the manual but it doesn't show it connected in the diagram. Very odd.
Ideal Logic Pump Overrun
- Thread starter Keith1978
- Start date
Well it sounds like pump overrun, but he did say it doesn't have it, I actually asked twice. As I said the terminal is there, it's shown in the manual but it doesn't show it connected in the diagram. Very odd.
I came across this site while trying to work out why my pump has been running continuously for months with my Logic Max H24, I confirmed Switch Live was being switched so not a valve issue, and the boiler was the cause.
The live out shown above is NOT switched live, but permanent live, there is a fuse direct from the mains live in to this output on the board.
So the CH engineer must also assumed this was a switched live for the pump, and hence the pump has never stopped. As temporary measure I have wired the pump live to the SL. I will rewire the CH system and disconnect the pump from the boiler, it can take the switched live from the central wiring ( will leave the cable - fully disconnected in case needed in future)
Question: All has been fine for a week, not sure if I should add a pump over run timer to the pump. What characteristics of the CH would determine if this is required?
This a pretty old thread but pump overrun is used to cool down the boiler HEX (heat exchanger) when the boiler is switched off by the programmer or the roomstat, if the boiler is asked to fire up again after say 10 minutes or so by the roomstat then it will be very difficult to get it away without burner cutout when the floww temperature reaches flow target temp+5C which it more than likely will as boilers fire up at ~ 65% of max output.
I have never heard of a gas boiler that doesn't use pump overrun.
I have never heard of a gas boiler that doesn't use pump overrun.
I Opened the thread as I realised I had the same issue. I understand what pump overrun is. I am asking as the ideal logic max h24 does not power the pump and therefore pump over run is optional ( there is an ideal kit that connevts to the central wiring to provide this), when is it must rather than a nice to have function?
I would say a must under the conditions I stated above or/and if you have smart TRVs which can cycle the boiler on/off frequently, they havn't got a stainless HEX so IMO a very desirable function but would then also require a automatic bypass valve (ABV) installed.
Thank you. I can confirm an ABV is fitted and was there before this boiler was installed. There are non-branded pump over run circuits for less than 20gbp, so I will install one to be on the safe side. At least the pump is no longer running 24 x 7. Cheers
I'm not a heating engineer but I do have an Ideal Logic heat only boiler. There is no pump overrun on mine but the flue fan does continue to run for ~ 2 minutes after the boiler stops heating, presumably this is to cool the heat exchanger.
Thank you, did you install an overrun or leave it without?
I didn't install anything. My heating engineer (very good and completely trusted by me) didn't install an overrun. Boiler has been working fine for about six years without an overrun.
Edit to add: I understand that the boiler requires a permanent live supply to allow the flue fan to continue to run when the programmer is no longer calling for heat.
Great feedback. Cheers
See my edit about the boiler requiring a permanent live supply when the programmer is not calling for heat, I edited my post while you were replying.
The boiler has a perm lne, and sl and that will remain. Just the pump will be connected directed to the central wiring on the sl (the same one that goes to the boiler)
The fan overrun of a few minutes will obviously cool the HEX to some extent but its main purpose I would think is (as a Post Puge) to expel any residual combustion gases from the boiler when the burner shuts down, oil fired domestic boilers are now incorporating this post purge as well.
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It is just odd that ideal removed the pump overrun connection on heat only models( i understand still there for combis), making the overrun kit optional. This confused my enginner ( who made the pump run 24 x 7, by using the boiler perm live output, intended for frost protection). Other forums suggest the confusion is not isolated to my engineer.
I am going to ask my emgineer to speak with ideal as he may have done this to other customers (it was 3 years ago), if need will add the 160gbp ideal kit, if nice to have will add the 20gbp generic circuit.
Cheers
Well, if they do use pump overrun in their system (with integral circ pump) boilers but not, by default, in their heat only boilers, its a bit disingeneous to say the least to offer it as a optional extra.
Vaillant heat only (series "4") boilers like the Ecotec Plus 424, 430, etc, as far as I know, do provide this as standard.
Vaillant heat only (series "4") boilers like the Ecotec Plus 424, 430, etc, as far as I know, do provide this as standard.
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