ideal classic ff350

rightjob!

hi..i replaced a faulty fan on an ideal classic.

the boiler fires up fine and works untill the cover is put back on. then the flame starts hunting and cuts out as if its being starved of air.

all the vacuum hoses are on corrrectly and not bloked.

anybody got any ideas??

shane0007

First off, are you an RGI?

rightjob!

yes RGI and oftec registered,should have stated that.

i changed one earlyer in the week,same model no problems.cant understand whats wrong.

shane0007

It can only be a balanced flue issue. The seal between the fan & the flue is most likely compromised and you are getting POC re-circulating or insufficient air intake from the balanced flue. This is why it is working with cover off.
Have you checked the air intake with your FGA for CO? Also check inside the boiler with cover off with your FGA. Have you a personal CO alarm? Always air on the side of caution with this type of issue, putting safety first.

rightjob!

i checked the co with my analyzer and there was no spillage.

i was thinking the only thing it can be is is combustion air but all seals seem ok.
i know by taking the cover off its adding more air intake.

something must be causing it. a fresh eye on it tomorrow maybe.

thanks for the reply

shane0007

Have you checked the flue externally for blockages?

rightjob!

yep that was the first thing i though of that maybe something went into it somehow.all was clean.

shane0007

You could prove air flow through the air intake with the negative pressure gauge of the FGA.

Mutha

Open forum, maybe go to RGI one? Chancers be watchin'.