It has been acknowledged that the similarities are there, but one store is retail and the other is wholesale. Any business man with a brain is gonna serve whom ever generates more profits. The reasons have been repeated and repeated it this thread, if the reasons don't satisfy you ask an owner...
But, it apparently IS different, because some HVAC suppliers choose not to sell to non professional installers, but AutoZone will sell to anyone that fogs a mirror.
Most will sell to the public, but it's not home depot. They wont sell you things that you need to have an EPA certification for. There not gonna tell you how to fix your furnace, and there not gonna let you return installed electrical parts that have been jammed back in the box because it...
So your thinking they oversized or put too many runs off air handlers? So when the fan slows down the duct static pressure is too low. I suppose it's possible, but it is a fine line, maybe you can get the contractor to come back with a balometer and manometer to really see what's happening...
I've never been carded for equipment, but certainty for refrigerant. Any supplier that doesn't collect license information from refrigerant purchasers certainly does have something to fear from the EPA, on line or otherwise. Pre-charged equipment, I'm really not sure about.
Is it just the wall units that overshoot, or all of them? With the wall unit it makes sense, cause the Tstat reading the space temp of the wall but the unit will run till it's internal sensor is satisfied. I've never seen one of the ducted air handlers, but I assume they use the Tstat like a...
Is the temperature overshoot issue a because the unit maybe has a minimum run time? There may be a parameter in the stat to change the deadband and aid shoot cycling, and in turn make it so that the unit needs to run for it's minimum time to make temp. Andy
It makes sense that you can't change the wall unit, I understand it not being ideal for you, but it makes sense. With the actual ductless units, having the constant circulation is the only way to keep the space at a consistent temp.
Fyi, I assume one of those parameters is for heating and one for cooling. I d think that if you were looking for cooling the fan wouldn't be a bad thing. The units were designed to have them running. I would consider just changing the fan operation for the heating cycle only.
The gas comes up through the floor near the water heater, right? You defiantly can't use one shut off for 2 appliances, plus the things already mentioned. I don't know the codes in your area, but it isn't an acceptable professional installation.
Can you post a pic of which t-stats you have, I made a few phone calls and think I have an answer. If you have the controllers I think you have, they look like standard Honeywell stats, you can go into the Setup Functions menu and change parameters 125 and 127 both from 1 to 2.
There is a guy at API in Manchester who knows everything there is to know about those, I forget his name, maybe Mike.... If you post up the model # I can call, we buy a lot of equipment from them for commercial applications.