Jaguar Boiler Overheating

29 Sep 2009
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United Kingdom
Hi All, I have a Jaguar 23k Combi boiler which appears to overheat, displaying F1 on panel. Sometimes the O/H Stat trips and has to be reset. seems to be too sporadic to be a blockage or pump fault. Any ideas?
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Thanks for your reply! Pump seems to be working, however a slight ticking noise can be heard! Regarding system pressure, seems to be holding at 1.2 bar, cant get it much above this, yet I know mains water pressure is much greater - could be a fault with expansion chamber - will check. I know the F1 sign is a front to a multitude of problems, but do you know if the OH stat will signal an F1 notice without locking out, or is that signaled by the flow stats?
Have noticed that pump is getting quite hot before the return pipe does. Pump may be seizing without me knowing, or slowing down. Will replace and report back! Any suggestions in the meantime greatly appreaceated!
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These boiler are inclined to overheat during their normal operation.

However, "normal" in the case of these cheap boilers usually means a rather dirty system.

If you set the CH maximum temperature to no more than 70° C then that will usually prevent th tripping on o/h.

You can take out the pump and see if the eye of the impeller is blocked.

The whole boiler would probably benefit from treatment with citric acid ( DS40 ) and perhaps also sulphamic acid ( DS3 ). But if you try that keep it out of the rads.

Resetting the o/h stat on some models involves opening the combustion chamber which a DIYer should not be doing.


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