fernox f4 express

[goafer]

I have previously blogged that I have a slight leak on the central heating side of my boiler, ie, the pressure gauge on the boiler of 1 BAR drops slightly after two days, with the boiler working, but not when all 16 radiators have been isolated with both the TRV and Lock shields closed, I am still trying to locate the leak, by opening each radiator individually, until hopefully I get some success, meanwhile it has been suggested that I try FERNOX F4 EXPRESS LEAK SEALER, my question is has anyone used this, if so what was the outcome, did it work, or, is it just another gimic??. From what I have gleamed it would appear the leak is not on the flow or return that feeds the radiators from the boiler, nor on the boiler itself, so by elimination must be one or more of the rads, but where exactly, appart from sleeping with it I have done almost everything else. Just posing the question re the FERNOX if all else fails, Goafer.

 

[Boilerman2]

With 16 Radiators the problem may be that the boiler's built in expansion vessel is not big enough to cope with the system volume an additional vessel may need to be fitted to accomodate the excess

as for Fernox F4 leak seal - it works on very slow leaks and is certainly worth a try after ALL OTHER AVENUES have proved fruitless use F4 before breaking up floor screeds, if it works great if not you know what you must do!!

 

[goafer]

Thanks boilerman 2, the system was working fine previously, and was designed to accomadate the number of rads in situ, for the record, the boiler is a Worcestor Greenstar 30CDI System condensing boiler, serving an OSO unvented indirect system tank. I will keep on trying each rad individually, and leave for two days to see if there is any pressure drop on the boiler, I have previously been doing this on a daily basis, when I suddenly realised the drop didnt occur until the second day, so have had to go back to the beginning and start all over again. If this fails I will try the Fernox route, I cant see the need for breaking any screed or lifting any floor boards as the flow and return pipework which services the radiators has maintained its pressure going into the third day with as I have said all the radiators isolated, but the boiler working, Goafer.

 

[goafer]

Just to finalise the outcome of the leak saga. I couldnt` locate the leak testing each rad individually, could have been more than just the one, used two tubes of f4 express leak sealant, one covers 10 rads, and todate the system is working as it should with no drop in pressure as previous. The manufacturer does not state how long this will last for, so will have to wait and see what happens. Goafer.