Toshiba rav164ah-pe reversing valve

[HeathT]

Hello all.

I have been looking at a tosh split that is stuck in defrost/preheat. As it is in preheat the indoor fan stops and comp freezes up. There is a signal to the solenoid coil on the 4 way valve and the coil is magnetizing so I would say the valve is stuck. Want I wanted to know is that I noticed a 2way valve, what is its purpose and do i need to be checking that too? Thanks in advance

[Brian_UK]

The valve may not be stuck.

Check for leaks on the system, if the charge is low then the operating pressures are low and the valve will not operate .

[HeathT]

Thanks, will check running pressures in cooling cos as I say in heating the unit will not come out of preheat so indoor fan not running. Spoke with Tosh tech and they reckon valve is stuck but i will definately try what you have suggested. Thank you

[HeathT]

One other thing with what you have said, will that be the case even though there is a signal for heating and the solenoid coil is magnetizing?

[Brian_UK]

Could be, I had one unit a few years back ,R22, that would freeze the indoor coil. The controls were set correctly and the valve was energised; tried a magnet with occasional success but...

Low pressures when the system was running. Tightened the odd weeping flare nuts and recharged system. Pressures came back up to what was expected and the reversing valve swapped over without any fuss.

[Loops]

Hi HeathT,

To answer your original question - the 2-way valve controls liquid injection to cool the compressor and is activated by a klixon a few inches up the discharge pipe just off the compresor.

This valve will have no effect on whether or not your system heats.

Brian is right in that low running pressures could be why the 4-way valve doesn't change over.

But if pressures are good and you are getting 240vac across the 4-way solenoid coil and you've got about 900 ohms resistance and still no heating then I think your valve is seized in the cooling position.

Cheers

Loops

[HeathT]

Thanks Loops. Is that resistance reading for the solenoid coil? Which sensor operates the defrost mode TE or TL and what is the range of resistance one should expect from a healthy sensor, I know it will vary depending on ambient temps. I will check all I have been told on Monday. I appreciate the advise

[HeathT]

Hello all, just an update. Checked running pressures in cooling, unit ok. Checked resistance through solenoid coil-ok. I also found some info on sensor temperature-resistance characteristics and have posted the link as some helpul info within. Changed reversing valve and presto heating mode back to normal. Thanks for the input


http://http://www.csd-ltd.net/downloads/files/Technical%20Handbook%20version%2011_5.pdf

[HeathT]

Sorry forgot to mention its page 64 and 65 of the document for the sensor characteristics.

[Brian_UK]

Thanks for the update HeathT and we're glad that you have resolved the problem.