Shower Temperature Fluctuations.

[Steve2401]

I have a Baxi Duotec 2 40 GA Combi boiler 8yrs old and Hudson Reed Exposed Shower. Recent problems with temperature fluctuations in the shower. It will be warm for 5 minutes then it goes cold for 3 mins then hot again, you get the idea. Have massive problems with Limescale, a water conditioner is my next project. I have recently had a new Diverter valve, and new DHW heat exchanger fitted to the boiler. In addition I have replaced the thermostatic cartridge in my shower and yes it is plumbed correctly with hot on left and cold on right and the cartridge was inserted correctly. System pressure also correct. Im still having the same issues with shower temperature fluctuation and will test the NTC temperature sensor with a multimeter tonight. No Fault codes displaying and CH is fine. Is there anything else I am missing other than the above, and help would be appreciated

 

[Aire]

How's the hot water at other outlets? Also have you lived in the house the entire time since the shower was installed? Has it ever worked properly? Do you have any other mixer taps or showers in the property?

 

[Steve2401]

Hi and thanks for your reply. Yes I have lived here the entire time and has worked properly for many years. No other mixers in property, I have checked the tap at kitchen sink but to be honest it seemed ok, although i have not had it running for 10 mins like the shower. It seems to be when the shower has been on a while, it rarely happens to me but im in and out of the shower, I have constant complaints though from my girls who shower longer. I have just removed the NTC sensor and it reads 9.7k ohms at room temp, my NTC should read 10k ohms at 25 degrees so not sure whether this reading means it is defective.

 

[townfanjon]

Steve , firstly keep out of your boiler unless you are qualified to touch it .
Acid test to see if its the boiler or shower , run a long bath mainly hot water and check if any fluctuating temps , if there is its a good chance its the boiler , bath full of hot water its a good chance its the shower .

 

[Steve2401]

I am aware that I should be qualified to touch anything Gas related, this does not to my knowledge stop me going inside my boiler and removing the NTC sensor. I will try a longer test with the bath/ tap tonight. I am really trying to ascertain if the divertor valve, DHW heat exchanger or NTC sensor are ruled out are there any other components that could cause Temperature fluctuation of DHW.

 

[Stigster]

I am aware that I should be qualified to touch anything Gas related, this does not to my knowledge stop me going inside my boiler and removing the NTC sensor. I will try a longer test with the bath/ tap tonight. I am really trying to ascertain if the divertor valve, DHW heat exchanger or NTC sensor are ruled out are there any other components that could cause Temperature fluctuation of DHW.

I'm afraid you are wrong on that one. By opening the case of the boiler you have then possibly (rare chance I accept) compromised the seals around the door. It sounds crazy I know but that is the reason. Damaged/incorrectly placed door seals = potential for harm.

Nobody here will give you any advice that involves taking the cover off your gas boiler, sorry.

 

[Steve2401]

What Gas work can be undertaken by other tradespersons? If the work requires replacement of a non gas component such as a circulating pump or control valve houses within the boilers decorative casing the work can be undertaken by another competent tradesperson providing the work can be done without compromising a combustion chamber seal. It then goes on to explain the difference between a decorative casing and a boiler which has integral casing. I am satisfied my boiler has a decorative case as per their definition and therefore I am legally allowed to do this work. The above is from the User PlumbersForums.net Instead - Copy the content, don't link to it.co.uk

 

[Stigster]

I am sure one of our GSR engineers will be along soon to clarify either way. DIY gas boiler work of any nature usually causes some discussion!

 

[Burger]

I agree with Stigster on this one, I e attached a couple of screenshots, two being from your boilers installation instructions, the other from Gas safe’s website regarding decorative cases.

 

[Aire]

What Gas work can be undertaken by other tradespersons? If the work requires replacement of a non gas component such as a circulating pump or control valve houses within the boilers decorative casing the work can be undertaken by another competent tradesperson providing the work can be done without compromising a combustion chamber seal. It then goes on to explain the difference between a decorative casing and a boiler which has integral casing. I am satisfied my boiler has a decorative case as per their definition and therefore I am legally allowed to do this work. The above is from the User PlumbersForums.net Instead - Copy the content, don't link to it.co.uk

Some boilers have an external case which can be removed without exposing the combustion chamber. Which boiler do you have?

 

[Burger]

Just going over the posts again, check the head and hose for restrictions. Try running without either of them, see if it stays hot.
[automerge]1568998535[/automerge]

Some boilers have an external case which can be removed without exposing the combustion chamber. Which boiler do you have?

I have a Baxi Duotec 2 40 GA Combi boiler 8yrs old and Hudson Reed Exposed Shower.

 

[Aire]

Oops, literally the first thing he says is which boiler he had 🤪.
Steve, you can't touch your boiler without breaking the law.
You have a bath, no mixer tap on the bath? What's the age of the property? If it's a new build you may have a mixing valve under the bath feeding the hot tap. I would also check the shower head and hose as cbw suggests.

 

[ShaunCorbs]

If your other outlets in your property are ok give them a decent run to test then I would say your issue is with the hr shower most likely the cartridge

As for the boiler if you have / have to remove screws to Remove the front cover / case then this is part of the seal and must only be removed by someone qualified

As for boiler parts being replaced

If the cover is screwed then even if it’s a water part or a cable tie this must be done by a qualified person eg gas safe

If the cover just lifts off no sign of screws / anywhere for screws to go eg they’ve been lost / not put in then anyone can repair parts upto and not going any further than the combustion chamber and anything that interferes/ interfaces with the gas side for example

Pcb
Gas valve
Air pressure switch and more (etc)

Hope this helps