Adjust Charge pressure of expansion vessel to static head of central heating sytem

[Pete C]

Hi All,

just wondering if you can help me with the above statement as i am not

100% sure what it means. I have a got a Worcester Bosch greenstar 35 HE plus which i am going through the process of comissioning. it adviseses that I

"Adjust Charge pressure of expansion vessel to static head of central heating sytem"

But gives not explenation of what this means. Any help would be much appreciated.

Thanks in advance for any replys, much appreciated.

Pete

[FrancisJK]

Try

the general idea. Other manufactuers give different specs for their vessels.

I don't know about specs for your boiler.

See also:

Sealed CH FAQ

[fred]

In article , Pete C writes

Ok, static head of the system is the pressure displayed on your pressure gauge when the system is cold, expect say 1-1.5bar, so setting the expansion vessel pressure to that level, is pumping up the vessel (from the valve) to the same level as displayed, 1 bar being approx 14psi. This will result in the diaphragm sitting in a neutral position in the middle of the vessel when cold. As the system heats up, the water will expand, pushing the diaphragm and compressing the air or whatever gas is in there.

Note that this differs from the method in most faqs which require you to set the pressure to a set level when the system is depressurised - what, depressurise the system just to service it, I don't think so. This method is very much common sense to me.

HTH