Why does my heat transfer blows cold? SPARKY's

nzjay, May 20, 3:32am
BUT. and I keep asking this. IF the fan is actually running, there should be warm air at the outlet(s).
You haven't yet satisfied me that you know the fan is actually running. by seeing if a sheet of paper sucks up on the inlet, or if a strip of tissue is blowing away when held by an outlet.
If the t/stat is connected wrong, the fan should still go, just that the setting would need to be at a temp higher than the ambient in the inlet's room instead of lower.

jacqui248, May 20, 4:18am
YES sorry fan in definite running. i am not that stupid and like isaid i was in ceiling removing the ducts checking for holes etc etc

johotech, May 20, 5:33am
Well my point was that you really don't know if it is "cold" - Cold is a relative term. 27deg isn't really "hot", that is only warm.

If you have 27deg air (possibly slightly colder actually) coming out a vent at a reasonable velocity and you feel it with your hand, it won't feel hot or even warm, not like the air off a fan heater. Especially if you've just been sitting in a room which is 27deg.

The only other thought I had, was are you sure it is just a simple heat transfer system? - Which is just a fan taking air from one room to one or more other rooms? Was there definitely only a fan in the system when you looked in the roof? There was no other box in any part of the main duct (the duct from the living room to the fan, or just after the fan)?

I'm mentioning this because some circulation systems do have a boost heater in the system. Usually that would be a metal box about 40cm square connected in the main duct, with a wire connected to the box.

But I'm still not convinced that the air is cold. I think when you measure it, the air coming out will be maybe 1-3deg cooler than the air going in. That's as good as it gets for a heat transfer system.

jacqui248, May 20, 6:16am
well i should get a thermometer tomorrow and i will fill you in.

shakespeare6, May 20, 6:31am
Is this a wind up?
A thermostat turns the fan on or the fan off- that's all nothing else.
The same way you can use a switch to turn the fan on or turn the fan off.

If the fan switches on then the sparky has down his job. There's no other magic in there.
If 27 degrees is the set point then when the room temp reach 27 degrees it will turn on and stay on till the temp falls below it.

The other way to wire it is so the fan turns off at the set point - that would mean when the room temp is less than 27 degrees the fan will run when the room temp reach 27 degrees the fan will shut off.

It's really that simple.
If the airs going in at 27 degrees and coming out cold then it must be cooling down there's no other scientific explanation. Other than you have a leak but you said there isn't.

greys, Jun 28, 12:54am
Was this ever resolved?

What was the problem?

farmerjohn, Jun 29, 5:24am
It seems that no one has mentioned a possible cause to this problem.
What if the sparky wired it incorrectly, and the fan is going in reverse?

bill1451, Jun 29, 6:38am
The answer here is quite simple the sparky has hooked the thermostat up incorrectly, you want the fan to turn on when room with the log fire comes up to tempurature, or you have a split in pipe or pipe has become detached from one of the joins.

johotech, Jun 29, 6:48am
It isn't possible to wire those fans to run in reverse. It would have to be physically turned around in the duct, to work backwards.

johotech, Dec 4, 7:55am
If you read the whole thread, you would see those things have already been suggested.