Johnson & Starley J25/32 fan failure?

hello, i think my fan is on its way out. when i first turn it on it noisey and after about 1 hour the noise stops is it the fan or something more serius and also it doesnt feel as hot has it used to any ideas

Lisa Edwards
January 2011

All is well now, the motor rewound and reinstalled and is better than before more quiet and smooth as a new bearing was also fitted which is what caused the initial failure, the applaince was serviced back in May 2010, and it passed Ok then, I have cleaned the air filters, refitted everything back and checked the HE whilst the fan was out and sounded good with no cracks and any rust etc, vaccumed all around the cupboard and the mesh filter and the heating works fine now and another service is due in May again this year.

also bought a Kidde Night Hawk CO Alarm, which was tested to make sure it really works on co presence, so smoking a cigarette registered 47ppm within about 5 minutes, and the unit was reset completely and left in front of the warm air grill/vent/register as it may be called, and after running it for several days it has not even registered anything, not even a few PPM, so quite confident the system is safe. I also carried out some spillage test and draft test and all seemed fine as a smoke match indicated correct smoke suction through the bottom applaince vent so no downward draftb from the flue, (Spillage) and checked the flue by going up my loft and it seems quite sound and no cracks or displacement from the ridge.

Total cost to rewound the motor was under £50.00, so well pleased with the outcome.

Mike
January 2011

There is a thermal cut out which should turn off the gas if the fan fails. Even if this is working, the heat exchanger can crack from the excessive heat.
The good news is that J&S still sell new exchangers, the bad news is that they're £350 and the fitting is a bit of a nightmare. I know this because I'm in the same position - thinking of getting the whole thing replaced.

Jim
January 2011

Thanks you ever so much, appreciate your quick respond, yes i noticed that too in the past whenever i turned the room state on the fan would cut in a little later, so there is a temperature limter for the heat exchanger, that is quite reassuring then.

I will get an engineer organised the one who specialises in warm air units as many i spoke to had no clue about warm air units.

Mike
January 2011

You maybe mis-understand the way the unit operates, the burner fires without the fan in the first place, this heats up the heat exchanger before the fan kicks in otherwise it would be blowing cold air around the registers.
There is a limit stat that will cut the burner off if the fan doesn't kick in once a greater temperature is reached (it links directly through the wiring to the gas valve), however, if the unit cools sufficiently it will allow the burner to come back in again, until that same limit is reached, even without the fan running.
The heat exchanger can become damaged during overheat episodes so DO NOT use it until a gas safe engineer has checked it properly, using it without proper testing could prove to be potentially fatal

Carefree
January 2011