I have some descaler / cleanser circulating in my 8mm system. The instruction say it needs to be left in for 28 days.
As my system is a bit prone to airlocks if I drain it down I wondered what your thoughts are on leaving the pump running and opening one drain (through hose to outside) and just letting it flush through for a few hours. Do you think this will get rid of the cleanser or must I drain it right down?
You can do this - I have in the past.
However, be really careful about setting the drain to a very low flow rate. If you run the pump dry there is a fair chance of it seizing.
Really you will be doing increasing dilution. On the other hand, if your ground floor radiators are fed from above then this is better than draining down unless you are going to take those radiators outslde for a clean.
A good quality inhibitor afterwards (e.g. Fernox, Sentinel) is a good plan - not an area for cost reduction.
Radiators are fed from above - combi is upstairs as well. I don't mind draining a bucket full out of each radiator - I just don't want to empty the system. I guess the ball valve flow will keep pace with a drain c*ck on the hall radiator.
Will add an inhibitor - what is the current recommendation. I have always had one in the system but a couple of radiators have become sluggish - I suspect the pipes.
I would check that with pump off and see if any air enters.
Afterwards, the pump can be run without boiler usually by turning off the gas supply
On Thu, 19 Jul 2007 20:50:50 GMT, "John" mused:
A combi with gravity fed rads? Novel system, any reason for it?
System is 20 years old. I would rather it be mains fed but haven't dared change it in case leaks appear - not sure there is a real advantage in changing it.. Boiler (Worcester Heatslave - open flue) getting near to replacement date but scared of hassle of making the system comply to latest practice. I have Maxitwin valves and all the pipes either under chipboard or behind plasterboard. Don't want to contemplate the mess.
Obviously the DHW is mains fed.
On Thu, 19 Jul 2007 21:27:00 GMT, "John" mused:
Fair enough, not something I've come across myself, thanks. ;)
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