A heater blower a/c blower mod

[DaveMcKenz]

Hi guys,
I have been going through the process of reinstalling the previously deleted/trashed a/c system on my 84. I have SSI heat exchangers and have backdated the heat with ducts off the fan shroud. I had eliminated my engine compartment heater blower, but I saw a post by Wwest about using in without its shroud intake. This gave me the idea of using it as an a/c condenser fan. As Wwest points out, the air discharges past the engine, so it does not increase heat load to the engine. Anyway, we will see how it works. It was free for me to do. I used a relay to turn the blower on whenever the a/c clutch is engaged. power comes from the blower fuse in engine compartment, blower control jumpered to allow footwell blowers to work with heat levers.
BTW here are my a/c P & T's:
R134 H=225 PSI, L +28 PSI, OAT = 85 F, Vent temp = 38 F. So far, so good.
Here's a pic or two.
Dave

[wwest]

I'm assuming you plan to do the blower intake mod eventually, TRIVIAL DIY task.

In the meantime there is another simple DIY mod that can be used to avoid the blower running continuously whenever the clutch is engaged, say when the engine fan is adequate.

Assuming you don't wish to use/install the Red Dot 71R7500 trinary pressure switch.

Tape and insulate a Senasys thermostatic switch, P/N 2570F099-187, $9.75, to the high side hose nearest the compressor an is possible. Use the switch to supply power to your new relay.

Switch closes to activate blower at 130F (~200 PSI), opens at 105F (~160 PSI).

Blower then does not run unless needed, plus helps to keep the high side pressure at a more optimal level for condenser heat transfer efficiency.

Senasys -

[wwest]

[DaveMcKenz]

Thanks, I did the blower mod today. I like that switch. I am a little skeptical that there would ever be a time when I had a problem with too much air flow, and would want to turn off the auxiliary blower. I think my condenser comes right up to 200-230 in very little time, which means the blower would be switched on pretty quickly. Thanks for all the ideas.
Dave

[DaveMcKenz]

I am not sure you guys realize how clever this is, and I give credit to my sometimes opponent in rhetoric to Wwest for the idea. This is a condenser fan that does not add heat to the engine. It has some of the same advantages as moving an additional condenser out of the engine bay into a fender.
Dave

[Ronnie's.930]

So do you think that tiny little fan pulling a trickle of additional air across the tail condenser is going to result in lower vent temps? I look at it and think "no effen way", but will be interesting to hear your report on results. For example, you note 38 degree vent temps above, so what are the vent temps when you switch the fan off?

[wwest]

Originally Posted by DaveMcKenz

I am not sure you guys realize how clever this is, and I give credit to my sometimes opponent in rhetoric to Wwest for the idea. This is a condenser fan that does not add heat to the engine. It has some of the same advantages as moving an additional condenser out of the engine bay into a fender.
Dave

Not only does it NOT add heat to the engine, it subtracts some.