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Replacement parts for WHIRLPOOL RES7745PQ0 | AppliancePartsPros.com

Here is the wiring diagram
http://www.servicematters.com/d...0Sheet%20-%208528190.pdf

First shut the breaker off/on slowly a couple times. Sometimes you can loose half the line without actually tripping the breaker.The motor requires 120 volts but the heater and timer require the full 240.
Better yet check it with a meter
L1 to L2 should be 240 volts
L1 to Neutral and L2 to Neutral both should be 120 volts.
If OK check that the terminal strip in th unit is OK.

Next most likely would be the heater itself.
Remove one wire from it and measure it, should be approximately 10 ohms

Next the thermal fuse. This is the one on the heating assembly. Remove one wire from it and measure it, should be 0 ohms

[COLOR="Blue"]heater ohms out at 0[/COLOR]
Something is wrong here. It should read around 10 ohms.
0 is a dead short.
[COLOR="Blue"]
switch/relay "thingy" on the heater unit ohms out at zero too.[/COLOR]
I am assuming you mean the hi-limit thermostat (Item 15 in Section 3)
0 ohms is OK.

Item 9 in Section 3 Thermal Cutoff (fuse) should also be 0 ohms. If it is blown get back to us as there are things that you should check to find out why it blew.

Also Item 8 in Section 3 operating thermostat. Note: It is a thermostat with an internal heater so one set of connections are the contacts, they should be 0 ohms; the other set is the heater usually around 25,000 ohms.

Place the timer mid cycle in timed dry, timer switch 2 contacts should be closed 0 ohms.


Be sure to unplug the unit and always remove at least one wire from any device you measure for resistance, this prevents you from reading an alternate/parallel circuit path.

It may depends on what meter scale you are on.
For instance if you are on a 200K ohm scale it will read 0.
If on the 200 ohm scale it would read 10 ohms.

[COLOR="Blue"]heater on 200 ohms: 5.3[/COLOR]
This seems very low, would work out to over a 10,000 watt heater.
Most units are 4,000 to 5,000 watts

[COLOR="Blue"]Item 9 section 3...thermal cut off...: on 200k...4.3...on 200 ohms...I get nothing.......[/COLOR]
This looks blown to me
[COLOR="Blue"]
item 8 section 3, operating thermostat...on 200 ohms... reads: 00.2ohms..'thats the two big red wires, situated 'top' and 'bottom' on the thermostat. The two middle wires (purple, smaller gauge, on "200k" read 02.5...I got an indistinguishable number on 200 ohm setting[/COLOR]
Looks OK

So if I assume the thermal cutoff on the heater is blown there are a couple of things to check.
You will see that it comes with a hi-limit thermostat. This is because the hi-limit should have regulated the temperature so the cut-off did not blow.
Check the heating coil.
Unplug the unit and both wires to the coil.
Check it with a meter, should be around 12 ohms.
Then check from each side of the coil to the case/frame, both should be infinite ohms (open). If not the coil may have sagged or broken and is touching the case. This can cause it to run on high and the thermostats cannot regulate it.

If OK then also replace the hi-limit and clean/check the following
Vent system
Blower wheel
Seals Drum seals etc . The cycling thermostat is on the blower, air is actually sucked over the heater, through the drum and pushed out the blower so if you have a large seal leak the thermostat sees a cooler temperature and drives the unit hotter.

If all OK, be sure to check that you can vary the temperature after you get it back together.
If not the cycling thermostat's contacts are probably welded together and it also needs replacing.
Or you may want to replace it now as a precaution.

when I put my greenlee on 200ohm setting, and unplug all the lines to the heater, and test the two main terminals...it reads 5.3. When I take one to the frame (screw on the body), and one to the either of the terminals..it reads 1 . which is weird. I guess that's 'infinity' on this thing....??