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central heating switch on !


Dc
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I have this evening switched on our new central heating system which I installed (not bad for an ex IT guy) and as I type a warm glow surrounds me ! I would especially like to thank all the fantastic people who write on the forum who have helped me out and given me the confidence to go for it. I would like just a bit more help/advice from you if possible.

I have 14 radiators each with thermostatic valves, a 15/60 Grundfos pump and a 33 kw French oil fired boiler, used for the central heating only. I have installed the system the French way with a non-motorised vanne melange and was wondering about the following:-

What should the settings be for the boiler/water temp?

What should the setting be for the vanne melange?

What should the setting be for the soupape pression differencielle?

How do I go about balancing the system(where do I start)?

All help greatly appreciated!

regards

dc

 

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Boiler temp: depends on how much heat you need - start at 60C and adjust up or down by 5 deg until the system can heat the house generally well within half an hour. Avoid running it below 50C or above 80C (NOTE: >65C can cause a mild burn to a child's skin.)

Vanne Melangeuse - open fully (i.e. so all the flow is going pumpwards) and then close it VERY slightly. With 14 rads, you need all the flow you can get. Not sure why you have one?

Soupape pression differentielle - is it the type with a little ball in a phial?? Not many of them around nowadays. More later....

Balancing - interesting with a SPD. However, the principle is: Remove all TRV heads so the valves are all open, determine the farthest/largest rad. Open the lockshield valve on this fully then back off half a turn (to stop it sticking). Close all the other rads' lockshields fully, then open each to half a turn.

Fire the system up and allow it to come up to temp for 15 minutes, at 60C flow. Make sure the SPD is NOT bypassing at all. Make sure the pump is on speed 3.

Check that the fully open rad is very hot top and bottom. Feel the other rads top and bottom. Any that are NOT hot top and bottom need to have the lockshield opened half a turn. Adjust by degree, then move on to the next. Keep doing this until you have similarly hot rads all round. (If you have a problem acheiving this, try to throttle the fully open rad down a little - this is unlikely).

The scientific and correct way once this initial set up is done is to now measure the flow and return temp at each rad. The idea is to get a temperature differential across each rad of 10C +/- 2C. The lockshields are adjusted to achieve this. This takes time and patience. And shoe leather.

Once this is done, you check the flow and return dT at the boiler. This should be 10-12C. NOW you set the SPD and pump speed to achieve this. This can be "interesting". There are other ways of setting the SPD....but at this point the SPD should NOT be bypassing.

You can then pop your TRV heads back on. Set them to max for the moment.

You should now be able to adjust the SPD to JUST open at this point.

Now set the TRVs for comfort.

Good luck.

Make sure the system is air free, by the way before doing the above. It is normal to allow a day or two running and a final bleed. Bleed AFTER setting the initial pressure.

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