Combination Boiler Intermittent Hot Water Problem

[Gunner69]

Hi I currently have a Performa System 28i which I am currently experiencing intermittent HW problems on. First of all the Boiler is Upstairs and my bathroom is down stairs.

Running a Bath is Ok but on using the HW kitchen tap which is the furthest away the boiler does not recognise the need for hot water and so does switch on ? . In addition at times the hot water will not heat to the max 80 degrees when called for it will only go as high as 50 degrees ? .

Central Heating is Ok and heats up to max temp

Does anyone have any idea what is wrong or needs replacing to get the Hot water to work OK ?

 

[armourer]

"Possibly" it could be a perforated diaphragm on the diverter or a sticking actuating pin.
This boiler is very similar if not the same as the baxi 105e.

As for the temperature, you dont want 80 degrees it will take the skin of your hands. 55- 60 is fine if you are getting less than this check your flow rate as a common thing is not fitting the correct flow regulator.
Basically the water flows through the boiler quicker than it can possibly heat it, so comes out cool.
Try slowing the flow down by closing your tap to half pressure. If it then gets hot chances are its flowing through too quick.

 

[AWheating]

the recommend hot water temp is around 46*, around 50* from a combi is normal. 60* is needed if stored water. Combination boilers are not designed to give 80* hot water.

 

[diamondgas]

Gunner69, Are you saying the temp gauge display lights only get as high as 50 on hot water yeh? I'd be checkin the resistance of the thermistors first of all to make sure they're as specified. My hunch would be the hot water one is dickie but unless you check/replace them you'll not know! You could also have, as mentioned a problem with the flow switch diaphragm which is why with high demand, Bath, the flow is recognised whilst the sink could be lower! By-the-way, is the kitchen tap a mixer?

 

[Gunner69]

Hi Diamond Gas
Thanks for you information. In regard to your question , yes it is a Kitchen mixer with seperate knobs for cold and hot , when the hot is turned it chucks out the pre-heated water and then more often or not does not switch the HW on and if its does it only appears to come out luke warm and the temp gauage shows around 50. When the Bath is drawn it comes out hot and the Temp guage shows goes up to max 80. Once again thanks for your advice's so far and duly wait your further advice's.

 

[diamondgas]

Is the sink mixer temperature regulated? could be that it's faulty not the boiler if it is a temp mixer? I can't explain the different temp readings as the boiler should operate the same for any hot water demand unless you are seeing just the pre-heat operating when the sink tap is operated. Does the hot water indicator flash when ruining the sink tap or stay on permanent? If it's flashing then the flow to the sink is not being recognised by the boiler and the pre-heat is operating!

 

[Billy Bob Bob]

are you certain this is a system performa? you have a cylinder somewhere? the performa comes in system and combi formats

 

[Gunner69]

Hi Diamond Gas
Thanks for you information. The Kitchen mixer is a normal kind with independant control for both cold and hot . As stated my main concern is why it does not come on at all the majority of the time. The temp indicator is static when running the bath and so is not the pre heat. As you have said I will look at replacing the thermistors and check/replace the diaphragm first. If this fails I assume I will need to replace the actual divertor valve? . Thanks for help and any other advice let me know. Will let you know how I get on.

 

[Billy Bob Bob]

i think it would help if the op clarified what boiler they have in post 1 its described as a performa system 28i,now a performa system is a system boiler not a combi and a performa 28i is a performa instant combi

 

[Gunner69]

i think it would help if the op clarified what boiler they have in post 1 its described as a performa system 28i,now a performa system is a system boiler not a combi and a performa 28i is a performa instant combi

Hi Gas Man , Sorry to confuse the issue but this is a combi boiler Potterton Performa 28i
Regards Gunner69

 

[diamondgas]

Hey gas man .. it had me somewhat perplexed ... so many boilers.... so many similar names .. flippin worcester are a pan for it but so are many others!!!

Regards the concern Gunner69 .... check out the flow diaphragm first as it's one of the most likely to show deteriorating in par with the thermistors! ... Alas this isn't always a definitive science and sometimes you have to replace to eliminate!!!