Anyone else seeing a spate of sticking R/v's (4 way valve). Been in the trade since the eighties, and only ever changed one around 20 years ago for squealing noise apparent only at indoor. But recently seen 5, and suspect may find another one tomorrow.(2 brands of unit so far, 3 if correct about tomorrows one) - saginomiya and cqc valves so far . Symptoms are low heat output, unit at full speed, and outdoor very noisy. Or sometimes again low heat etc, and pressure reaching 600psi on r410 or 700 on r32 before compressor trips off. Large temp differences noted on valve inlets verus matching outlet, and often on cooling only one leg forming ice on surface. Some also had a high pitch squeal at valve. All had correct gas charges, and no evidence of bad workmanship or air in system. Fault often also manifests as failure to return from defrost mode.
Curious if for some weird reason i alone am finding these issues, but i do tend to get second opinion and warranty calls. 2 systems were just under 5 years old, 1 was 3 years and 2 were under 2 years(1 x r410 1 x r32).
gpg58,
Aug 21, 11:23am
Ps re slightly short of 600 and 700 psi, units try to reduce by ramping back to minimum speed before tripping. Error code if available/logged, of over current although at minimum speed.
210sback,
Aug 21, 11:49am
What brand units?
gpg58,
Aug 21, 4:23pm
I think the brand of valves is more relevant (mentioned above), possibly fitted to a number of mainstream brands. But as 2 brands of valve so far, do wonder if something else is cause (lude oil breakdown etc).
tegretol,
Aug 22, 7:41pm
Have 4 Hitachi RAC-35YH units here, all <5yrs old. All four have suffered this and in all four, the solution was to unplug the solenoid from the control board, clean the pins with CRC and replug them. The required 18v DC (I think - it may have been 22v, was a weird voltage but is shown on the circuit as a tp) was there when the thing was told to cool and not there when in heat mode so wasn't the board. So dunno what brand you are talking about -couldn't tell ya what valve brand these units use.
gpg58,
Aug 22, 7:57pm
Cheers. Different issue though from that description, a complete spare control assembly including sensors and coils did not fix latest one. Some of them were power on for heat and some off, but not coil voltage related for any of them.
But while coil was energised on last power on for heating one, pulling it off valve and back on a number of times while at high pressure did free it up after a number of cycles, and unit then worked fine, but expect it to get sticky again soon though.(yes aware coil will burn out real quick if left off for long at all)
For operating valves when power off, i have found a good size super magnet on valve stem with coil off, will do the trick.
Doesn't look as smooth inside as what you'd expect. I haven't replaced one for a lot of years. Are you doing these as warranty repairs? It would almost be cheaper just to replace the whole unit wouldn't it?
gpg58,
Aug 22, 8:40pm
correct, outdoor only. 4 were, 5th is out of warranty, but as going again now, landlord waiting to see how soon fault returns.
Also find the black marking interesting, pics were 5 year old one. another 1.5 year old one was similar, but discolouring much milder. Did see some scraping marks too, and noticed seal mounting surface not square to slide, which MAY have let seals metal retainer to touch body. https://trademe.tmcdn.co.nz/photoserver/full/855723243.jpg Other 2 not pulled out /apart yet.
johotech,
Aug 22, 9:00pm
Don't think I've ever bothered to pull one apart before. It's probably 20 years since I replaced one. Much bigger units though. I thought they had more of an actual "piston" type thing in them.? Maybe in the larger ones - or maybe just in the old days ;)
gpg58,
Aug 22, 9:24pm
Yup definitely toys compared to real stuff, and unlike old school stuff, all brands are using some chinese made components in them now day's, much to my annoyance. Ps for those not seen one before, there is a plastic piece sits in the oval hole in center of slide, which has the ports shape in it.
You do know that most of heat pump components are from china , despite the name on it . thats why so many failures probaly 1 manufacture.
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