Mid Position of 3Port Diverter

[eyeofthebeholder]

Hi Guys,

We have just replaced our boiler, rads and other parts of the system including the diverter.

The Valiant boiler (618 System boiler) we had installed has a setting where you can set the diverter to the mid-position when there is a call for heating and hot water. It is described in the VR65 manual. The boiler setting is d.70. (Note this is not the same setting as the filling setting where the boiler sets the diverter to the mid position allowing filling of both HW and CH sides)

Are there any issues in setting this?

The only reason why I am asking this is that at the moment we have the timer configured to heat the HW at a completely different time to the CH. If we set the timer to call CH and HW within the same period...

eg:
HW: 16:00 > 18:00
CH: 16:00 > 21:00

...this would then heat both equally and theoretically use less gas as you are not heating them at two different times. If the HW cylinder got up to temp, the diverter would then move to CH only.

Am I talking c**p or is there something in it?

Cheers

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[doitall]

Would it cost more to heat 2 x 1gallon buckets of water separately or at the same time

Theoretically, yes it would be better to heat both buckets together because the condensing boiler will stay in the condensing mode longer with the bigger volume, in reality it probably makes no difference.

The prof will be along later

 

[eyeofthebeholder]

If it is theoretically more efficient I wonder why they don't set it by default?

I have noticed that there is a temperture difference when heating the CH to HW. Whatever I set the dial to (other than off) on the HW, it always heats to 80deg (which is manually set in the diag options). The CH side can be set on the dial, but doesn't go up as high - I wonder if it's got anything to do with that??

If I set the CH to say 50deg and the valve was in the mid position, I wonder what the boiler would heat the water to?

Cheers

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