Only warm hot water - Possible new boiler?

[wiffers2003]

I need your help/advice please.

I have a Potterton Performa 24 Combi boiler which is just not good enough for our daily use in this cold weather. I can't seem to run a bowl of hot water for washing up no matter how low i turn the tap so that the water comes through slower, i have to turn it down so much that then the boiler cuts out (as it doesn't see the demand for the HW) and i have to wait for ages again for it to heat up the next lot of hot water. I can only get a bowl of just above luke warm water and have been boiling the kettle to top it up.
Bath's have unfortunately become a thing of the past, as it just impossible to run a hot one!
This is wasting far too much water and gas as both are metered...uurrgghh!

Firstly, is this literally because the cold water into the boiler is so cold.
Secondly, could you please recommend a replacement combi boiler (of a much higher rating) that would make a good upgrade.

Thanks in advance
Carl

 

[mickyg]

Althought this is a low power combi, it sounds like its under performing. I used to have the exact same boiler in my first flat, and it was perfectly adequate for day to day use. The 2 most likely causes are a failing diverter valve or a contaminated plate heat exchanger. You can check the diverter by feeling the heating pipe from the boiler when the tap is on, it shouldn't increase in temperature. Also when you have a tap on full watch the flames on the burner, if the tap is luke warm then you should expect the flames to be up high. If they get lower or go off all together your plate heat exchanger is likely to be the fault. All in all these boilers aren't too bad, and generally easy to repair. However if your wanting to run baths and open more than one tap at a time then it may well be unsuitable.

 

[namsag]

Also if your gas supply to it is 15mm instead of 22 this will show up more in the winter when the water coming in is colder.

if your thinking of changing it the performa 30he baxi 105he will both fit straight onto the existing bracket with no alteration to existing pipework and flue hole will prob need an extra inch out the top
If your existing pipework does not go up the back of the boiler you could also put a duotech 33 onto bracket but flue hole will need moving 4 inches to the side

 

[gavinda]

i reckon it just needs some essential maintenance as mentioned. ok its not the greatest boiler out there but its way to young to be given up on... the plate ex probly is the big issue here but not to difficult or costly to sort either.

 

[Tipper]

If you're in a hard water area and have no water softening then the heat exchanger(s) and diverter valve may be scaled up.

Get an experienced combi boiler man to check it out for you and recommend the best course of action.

 

[bengasman]

Bit drastic to replace the boiler without having it checked.
5 will get you 10, it is a fairly simple repair.

Would I be far of if I guessed the boiler has not been serviced for quite a while and the benchmark has gone missing?

 

[wiffers2003]

We've only lived in the house for just over a year so not sure when it was last serviced, if at all !!!!!

Thanks for all your suggestions, the gas pipe is definitely only a 15mm and i'll look into the other idea's and let you know.
Are these something that i (as a fairly capable DIYer) could tackle or is it a specialist job????

thanks again
Carl

 

[wiffers2003]

Might phone British Gas tomorrow to get is serviced etc, are these reasonable and trustworthy?

 

[bengasman]

no, no, and no.
ask friends and neighbours for a reliable local RGI. BG charge a fortune whether you get an good engineer or a total muppet, and will probably try to sell you a new boiler, change of gas supplier, a powerflush and insurance, if not double glazing.

 

[wiffers2003]

I got a plumber to take a look and he confirmed it to be "the plate heat exchanger is most likely blocked due to hard water". He is booked in to replace the plate heat exchanger next week as well as give the boiler a service.
Thanks for your advice, i'll let you know of any improvements once its been done.

cheers
Carl

 

[wiffers2003]

Hi people,

So the boiler man removed the 10 plate heat exchanger only to find that it was actually not blocked at all. Fittted the new one anyway as already had it.

It turns out it was the diverter valve diaphram which was gunked up, as the little pin wasn't coming our properly to switch the microswitch. He replaced the diverter valve and we now have scolding hot water and the shower is like we've just had a new power shower fitted )

He said i should get a repair kit for the diverter valve, repair it, and keep it as a spare so i'll probably do that. He also suggest to descale the heat exchanger and keep that which all sounds like good advice.

Thanks again for all your top tips, Carl