I'm foxed

[TimShoubridge]

I fitted a Davies Craig fan last year and was not happy when we went to Brands as when it kicked in (low setting to test) nothing seemed to happen. well, time passes and other priorities come along.

So, now I come to check things over for next weekend I find I was right. However, I can't see the problem so need help. The fan documentation states it is supplied preconfigured for upstream mounting, in front of rad. I have a revotec switch and sensor in the rad and the wiring is:

perm 35A feed from battery to pin 30 on relay.

pin 85 on relay to earth.

pin 87 to live on fan

fan earthed.

No over-ride switch yet.

Fan works perfectly with switch although when it fires up the blades seem to rotate the wrong way. Air is pushed out of the grill rather pulled through.

The manual says to take the fan apart and reverse bolts etc. etc. but I don't have time.

Any suggestions? (other than bin it or live with it? :P)

[milothedog]

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Hi Tim, from what you have written there is no feed to the relay on pin 86 to pull it in unless I've missed something.

Normally on a relay 85 & 86 are for the coil and 30, 87 are the switch contact, if it's 5 pin 87a is made at rest.

a quick test to check it's working is to put a meter or test light on 87 when it working if you have power it's pulling in and the contacts are making.


Ian.

[TimShoubridge]

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Sorry Ian, when I re-read my post it's confusing. Bottom line is fan is working but seems to be reversed......suck not blow. Can I just rewire or do I have to reinstall?

[milothedog]

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I would assume if it's a straight forward DC motor reversing the polarity would make run backwards provided it's not earthed through its casing as that would cause a dead short. does it have a Pos & Neg lead coming from it.

The other thing is are there any electronics inside it, if so then it's probably designed to run in one direction, it may have diodes fitted which would prevent it running backwards as well. I suppose you either try it and see and take a chance on damaging it or do as they suggest and reverse the blades. sorry I cant help more

Ian.

[Andrew S]

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Hi Tim, look at No3

http://www.daviescraig.com.au/Therma...s-content.aspx

Cheers

Andrew

[TimShoubridge]

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Thanks chaps. It would appear there's a problem with the fan. It is not moving air as peer the labels on the shroud (Q3 on Andrews link). It needs to come out (along with rad et al). Going to be tight for Brands.