Is my CH system correctly vented?
My CH system has been consistently temperamental since it was fitted 18 yrs ago. Is the cause the design of the venting?
The system comprises of a Potterton RS 80 boiler,servicing the hot water cylinder and central heating (manifold with 8 radiators) via the 3 port valve.
The venting pipe to the expansion tank is situated between the pump and the 3PV. It’s a 15mm pipe and also serves as the return pipe or filling pipe for the system.
Is the HW side of the circuit properly vented? or does it need a second expansion pipe on the feed or return of the HW?
Should there be a separate return pipe?
Should any vent pipe be 22mm?
The problems encountered with the system can involve it just not working at all on occasions. I do not bother to use any preset times for the programmer but simply turn on HW or CH as required.
It usually works if the HW or CH are on. Problems are more likely to occur when the 2 circuits are used together or switch between. So I may have the heating on, then put the HW on boost for1 hour. After the HW has turned itself off the CH may stop.It seems to create air in the system and the pump stops going. If the system is then left off for several hours it will then work again.
Help please.
Fred
