Luke warm water from Vaillant Combi Boiler

[Dougie212]

Hope someone can help here....

The hot water from my vaillant combi boiler is all but luke warm. The heating temp is brilliant, gets nice and hot really quickly, but the water doesn't heat up much at all. The boiler fires up and lights when the hot tap is turned on, but it's as if the temperature isn't up high enough. I have found the instructions and it does point out that there is a water temp adjuster, but, the previous occupant of the house has very kindly broken the plastic cover of the adjuster wheel, and squished the metal tap with his pliers. Now I cant get it to move, and dont want to squeeze to hard incase it breaks.

Anyone got any suggestions as to whether the tap can be replaced, or if there's another way of reducing the flow to heat the water up more.

I have had the boiler recently serviced and all the parts are in good working order, which leads me to believe that its the water flowing through too quickly to heat up enough.

Thanks - Doug

 

[andrew1210]

Does the water get warm enough when you reduce the flow at the tap? This would create the same effect as restricting the flow through the boiler

 

[Dougie212]

well.... below the boiler is a tap that i assume is the in flow to the boiler... that would appear to be closed... in the off position, futher down that pipe is a small black tap that is used to top the boiler up.. should the bath style tap be on all the time..?? i've tried turning it but it doesn't appear to adjust the flow at the tap.

 

[andrew1210]

Sorry, i meant reduce the flow at the actual hot tap at the sink, does it get warm enough?

 

[Dougie212]

ah, see what your saying, no.... that has little effect.....

 

[Agile]

If you are getting hot water from your taps then that valve is open.

You get exactly the same effect by only turning taps on part way.

You boiler should heat at least 8 litres per minute to be pretty hot.

There could be other problems with the boiler. Has it been properly serviced recently?

Tony

 

[Dougie212]

yeah, serviced about 2 months ago...... the engineer was from the gas safe register, and told me that the boiler was in tip top condition...

 

[Dougie212]

also noticed that if the central heating is on, and i use the hot water the central heating can go off..... could this be the diverter valve..?

 

[Agile]

You need to tell us EXACTLY which model or a very good description of the front panel.

With the heating cold, do the rads heat up when you take hot water for five minutes?

Tony

 

[Dougie212]

no, they dont heat up after 5 mins of hot water, and its a vaillant VCW GB221 H..

 

[Agile]

In that case the diverter valve seems to be OK.

The boiler stops giving heating when you are taking hot water.

Can you set the hot water flow rate to 8 litres per minute at a tap and do a gas rate at the meter? See FAQ on Gas Rate.

Tony

 

[Dougie212]

hmmm... all sounds a bit complicated. i'll ask the guy who serviced it... just out of intrest, the temp adjuster has been squished by someone with their pump pliers, and as such cant adjust that. is that a relativley easy thing to change..?

 

[Dougie212]

anyone else any suggestions as to what may be causig this??