Combi queries

[davidm]

Hi,

Just had a combi fitted and have a few questions I hope someone can help me with...

The combi is a Worcester Bosch 28 CDi

1. How long should it normally take for the water coming out of the taps to get hot? I know it's never going to be instant, but it often takes upto 2 minutes... is this normal?

2. Sometimes the hot water is cloudy/chalky - the installer said it was quite normal and nothing to worry about, but I never had this with the non-combi boiler.

Thanks for any help and advice you can give,

Dave.

 

[masona]

The combi is a Worcester Bosch 28 CDi
1. How long should it normally take for the water coming out of the taps to get hot? I know it's never going to be instant, but it often takes upto 2 minutes... is this normal?

All depends how good your water pressure is and how far the length of pipe from combi to hot taps.

Not sure about your cloudy/chalky water colour which should've been flushed out by now.

Wait & see what the plumber's think as it will be quiet over the w/end

 

[oilman]

Calculate the volume of the pipe from the boiler to the tap and then divide this by the flow rate to give the time for water to get from the boileto the tap. BTW did you get the flow rate of the mains measured before you had the boiler fitted?

Next, is the water really chalky, or is it air bubbles?

 

[davidm]

thanks for the replies guys,

The installer mentioned nothing about measuring flow rate before hand...I wish I'd found this forum a week ago

How would I go about measuring the flow rate now? Once I know this, I can use your formula to get time to tap.

As for the chalky water...if I fill a glass, it looks very cloudy at first, gradually becoming clear from bottom to top over about 60 seconds.
It looks like there are millions of tiny particles/bubbles in there.

Dave

 

[COG]

don't worry about the cloudy water its basically the calcium being stirred up ,it settles down when you let it stand, worcester publish a little booklet about it, its more common the slower the flow rate. An easy way to calculate how long the boiler takes to heat up and reach the taps is to run it up to temp at the tap in question on full flow then shut the boiler down and time it until the temp drops off at the tap,that will be the length of time it takes the water to get from the boiler to the taps as the 28cdi has no storage.

 

[oilman]

To measure flow rate, find a tap nearest to the incoming mains, and fill a container at full rate for 6 seconds. Then multiply ot by 10 for litres/minute.

As you noticed, the "particles" are bubbles. I found this when someone was telling me how much clearer filtered water was than tap water. I just happened to leave a glass of tap water standing for 1/2 hour. It was as clear as filtered water.

Just as useful as fitting a magnet on your fuel line to improve economy.